Storm Active: November 14-
A tropical wave moved through the Caribbean sea during the second week of November and began to interact with a large gyre located near central America. This combination produced heavy rainfall in Jamaica and Hispaniola as it passed by and began to organize. The system was designated Tropical Depression Nineteen just northeast of Honduras early on November 14. Conditions in the southwest Caribbean were very favorable for strengthening, but the cyclone was very close to land and the circulation was quite large, preventing quick intensification.
Unfortunately, the depression still managed to intensify into Tropical Storm Sara that day and slowed down to a crawl just off the northern coast of Honduras. This led to a prolonged flooding event for the country, and surrounding areas.
As of 7am EST on November 16, 2024, Tropical Storm Sara had maximum sustained winds of 45 mph, a minimum central pressure of 999 mb, and was nearly stationary. For more up-to-date information and the latest watches and warnings, please consult the National Hurricane Center.
Saturday, November 16, 2024
Monday, November 4, 2024
Hurricane Rafael (2024)
Storm Active: November 4-10
Around the beginning of November, a broad area of low pressure formed in the southwestern Caribbean, a typical occurrence for that time of year. The disturbance gradually consolidated over the following few days and a closed center appeared on satellite imagery on November 3. On the 4th, enough convection had developed near the center for the system to be designated Tropical Depression Eighteen. Favorable conditions allowed it to strengthen into Tropical Storm Rafael later the same day.
Rafael turned northwest and passed just west of Jamaica during the morning of November 5. Steady intensification continued as the storm's organization increased, but it was kept in check by some dry air entering the circulation from the north. That night, Rafael managed to build a more complete eyewall and strengthen more rapidly. It reached hurricane status while passing the Cayman Islands. An eye cleared out occasionally on satellite the next morning, and Rafael peaked as a major hurricane early in the afternoon with winds of 115 mph and a central pressure of 956 mb. Very soon after, the hurricane made landfall in western Cuba.
Passage over land weakened the storm a little, but it soon entered the Gulf of Mexico as a category 2. Ocean temperatures remained very warm in the Gulf and Rafael made a comeback on November 7 when its eye made another appeareance and deep convection surrounded the center. That night, the hurricane reached its overall peak intensity of 120 mph winds, also matching its previous minimum pressure of 956 mb. This also matched the record for strongest winds recorded in a November hurricane in the Gulf of Mexico that was set by Hurricane Kate in 1985.
A developing ridge turned the hurricane west across the Gulf, where it soon encountered moderate wind shear and an extremely dry air mass. Though the storm had plenty of ocean heat content to work with, dry air steadily devoured Rafael and it weakened quickly from that point. By the evening of the 8th, it was a tropical storm. The storm slowed down and began a tight clockwise loop as it continued weakening. Rafael became a remnant low on November 10. The low dissipated soon afterwards.
The image above shows Rafael near peak intensity in the Gulf of Mexico.
Rafael had a destructive landfall as a category 3 in Cuba before moving into the Gulf of Mexico. Unusually (and fortunately), the storm dissipated over the Gulf rather than making any further landfall.
Around the beginning of November, a broad area of low pressure formed in the southwestern Caribbean, a typical occurrence for that time of year. The disturbance gradually consolidated over the following few days and a closed center appeared on satellite imagery on November 3. On the 4th, enough convection had developed near the center for the system to be designated Tropical Depression Eighteen. Favorable conditions allowed it to strengthen into Tropical Storm Rafael later the same day.
Rafael turned northwest and passed just west of Jamaica during the morning of November 5. Steady intensification continued as the storm's organization increased, but it was kept in check by some dry air entering the circulation from the north. That night, Rafael managed to build a more complete eyewall and strengthen more rapidly. It reached hurricane status while passing the Cayman Islands. An eye cleared out occasionally on satellite the next morning, and Rafael peaked as a major hurricane early in the afternoon with winds of 115 mph and a central pressure of 956 mb. Very soon after, the hurricane made landfall in western Cuba.
Passage over land weakened the storm a little, but it soon entered the Gulf of Mexico as a category 2. Ocean temperatures remained very warm in the Gulf and Rafael made a comeback on November 7 when its eye made another appeareance and deep convection surrounded the center. That night, the hurricane reached its overall peak intensity of 120 mph winds, also matching its previous minimum pressure of 956 mb. This also matched the record for strongest winds recorded in a November hurricane in the Gulf of Mexico that was set by Hurricane Kate in 1985.
A developing ridge turned the hurricane west across the Gulf, where it soon encountered moderate wind shear and an extremely dry air mass. Though the storm had plenty of ocean heat content to work with, dry air steadily devoured Rafael and it weakened quickly from that point. By the evening of the 8th, it was a tropical storm. The storm slowed down and began a tight clockwise loop as it continued weakening. Rafael became a remnant low on November 10. The low dissipated soon afterwards.
The image above shows Rafael near peak intensity in the Gulf of Mexico.
Rafael had a destructive landfall as a category 3 in Cuba before moving into the Gulf of Mexico. Unusually (and fortunately), the storm dissipated over the Gulf rather than making any further landfall.
Saturday, November 2, 2024
Tropical Storm Patty (2024)
Storm Active: November 1-4
Near the end of October, shower and thunderstorm activity began to concentrate near the center of a non-tropical low pressure system located over the open subtropical Atlantic. The system moved eastward and separated from the surrounding frontal boundaries. By November 1, it had the characteristics of a subtropical cyclone. Since it was already producing gale-force winds, it was named Subtropical Storm Patty. Patty had a small core where vertical instability supported some deep convection, but the entire cyclone was embedded in a cold air mass, contributing to the "subtropical" designation.
The system strengthened a little and veered south of east, reaching peak sustained winds of 65 mph. On November 2, the storm reached the Azores, passing just south of the western islands before turning east and directly over the eastern islands the following day. Wind shear over the storm increased on November 3 and Patty's strength gradually diminished as it finished its passage over the Azores. Rather unexpectedly, the cyclone transitioned into a fully tropical storm that night. The overall trends did not change, though. Progressively chillier water and high shear snuffed out Patty's remaining thunderstorm activity and it dissipated on November 4. By that time, the system was not far from western Europe; what was left of it brought some rain to Spain and Portugal soon after.
The image above shows Patty as a small subtropical storm on November 2.
Patty brought tropical storm conditions to portions of the Azores.
Near the end of October, shower and thunderstorm activity began to concentrate near the center of a non-tropical low pressure system located over the open subtropical Atlantic. The system moved eastward and separated from the surrounding frontal boundaries. By November 1, it had the characteristics of a subtropical cyclone. Since it was already producing gale-force winds, it was named Subtropical Storm Patty. Patty had a small core where vertical instability supported some deep convection, but the entire cyclone was embedded in a cold air mass, contributing to the "subtropical" designation.
The system strengthened a little and veered south of east, reaching peak sustained winds of 65 mph. On November 2, the storm reached the Azores, passing just south of the western islands before turning east and directly over the eastern islands the following day. Wind shear over the storm increased on November 3 and Patty's strength gradually diminished as it finished its passage over the Azores. Rather unexpectedly, the cyclone transitioned into a fully tropical storm that night. The overall trends did not change, though. Progressively chillier water and high shear snuffed out Patty's remaining thunderstorm activity and it dissipated on November 4. By that time, the system was not far from western Europe; what was left of it brought some rain to Spain and Portugal soon after.
The image above shows Patty as a small subtropical storm on November 2.
Patty brought tropical storm conditions to portions of the Azores.
Sunday, October 20, 2024
Hurricane Oscar (2024)
Storm Active: October 19-22
A tropical wave moved off of Africa on October 10. A low pressure center soon formed in association with the wave and the system trekked steadily across the tropical Atlantic. Along its journey, the low had a pretty well-defined center and was on the verge of tropical cyclone status multiple times, but was unable to muster enough convection to get there in a dry atmospheric environment. On October 18, the low passed just north of the greater Antilles and found another opportunity north of Hispaniola. It was finally named Tropical Storm Oscar during the morning of October 19.
Making up for lost time, Oscar ramped up quickly. Aircraft reconaissance found that the small storm had launched to category 1 hurricane strength by the same afternoon. A ridge north of the cyclone pushed it west-southwestward and the hurricane passed among the Turks and Caicos that evening, including a direct landfall on Great Inagua island early on October 20. The storm slowed down as it approached eastern Cuba that afternoon and made landfall near the country's eastern tip with maximum sustained winds fo 80 mph and a central pressure of 986 mb.
After landfall, Oscar stalled as the steering ridge was replaced by a trough that slowly turned it back toward the north. Its interaction with mountainous terrain weakened it quickly to a tropical storm and disrupted the circulation. During the afternoon of October 21, the storm finally reentered the Atlantic as a minimal tropical storm. It moved northeast into the Bahamas and brought some rain there, but atmospheric conditions had become much more hostile and Oscar was unable to improve its poorly defined structure. The cyclone ultimately dissipated the next day.
The image above shows tiny Oscar just after being upgraded to a category 1 hurricane. The storm was small but made multiple direct landfalls.
The track above shows the full path Oscar and its progenitor system (points where it was not a tropical cyclone are triangles). The system finally developed only near the end of its journey of thousands of miles.
A tropical wave moved off of Africa on October 10. A low pressure center soon formed in association with the wave and the system trekked steadily across the tropical Atlantic. Along its journey, the low had a pretty well-defined center and was on the verge of tropical cyclone status multiple times, but was unable to muster enough convection to get there in a dry atmospheric environment. On October 18, the low passed just north of the greater Antilles and found another opportunity north of Hispaniola. It was finally named Tropical Storm Oscar during the morning of October 19.
Making up for lost time, Oscar ramped up quickly. Aircraft reconaissance found that the small storm had launched to category 1 hurricane strength by the same afternoon. A ridge north of the cyclone pushed it west-southwestward and the hurricane passed among the Turks and Caicos that evening, including a direct landfall on Great Inagua island early on October 20. The storm slowed down as it approached eastern Cuba that afternoon and made landfall near the country's eastern tip with maximum sustained winds fo 80 mph and a central pressure of 986 mb.
After landfall, Oscar stalled as the steering ridge was replaced by a trough that slowly turned it back toward the north. Its interaction with mountainous terrain weakened it quickly to a tropical storm and disrupted the circulation. During the afternoon of October 21, the storm finally reentered the Atlantic as a minimal tropical storm. It moved northeast into the Bahamas and brought some rain there, but atmospheric conditions had become much more hostile and Oscar was unable to improve its poorly defined structure. The cyclone ultimately dissipated the next day.
The image above shows tiny Oscar just after being upgraded to a category 1 hurricane. The storm was small but made multiple direct landfalls.
The track above shows the full path Oscar and its progenitor system (points where it was not a tropical cyclone are triangles). The system finally developed only near the end of its journey of thousands of miles.
Tropical Storm Nadine (2024)
Storm Active: October 19-20
Around October 15, a broad low pressure system formed in the southwestern Caribbean just east of Nicaragua. The system drifted northwest only very slowly over the next few days, but brought heavy rains to a broad swath of central America. In the early hours of October 19, it became organized enough to be designated Tropical Storm Nadine east of Belize. Nadine organized rapidly but was quickly running out of water as it moved due west. Just before noon, the storm made landfall in Belize with peak winds of 60 mph. After landfall, the storm weakened steadily. It weakened to a tropical depression over Guatemala and turned west-southwest until dissipation on October 20.
The image above shows a strengthening Nadine just before landfall in Belize.
Nadine was a short-lived but large tropical storm which had significant flooding impacts.
Around October 15, a broad low pressure system formed in the southwestern Caribbean just east of Nicaragua. The system drifted northwest only very slowly over the next few days, but brought heavy rains to a broad swath of central America. In the early hours of October 19, it became organized enough to be designated Tropical Storm Nadine east of Belize. Nadine organized rapidly but was quickly running out of water as it moved due west. Just before noon, the storm made landfall in Belize with peak winds of 60 mph. After landfall, the storm weakened steadily. It weakened to a tropical depression over Guatemala and turned west-southwest until dissipation on October 20.
The image above shows a strengthening Nadine just before landfall in Belize.
Nadine was a short-lived but large tropical storm which had significant flooding impacts.
Saturday, October 5, 2024
Hurricane Milton (2024)
Storm Active: October 5-11
Around the end of September, a tropical wave moving through the Caribbean interacted with a broad area of rotation over central America to produce a large area of disturbed weather. This disturbance moved northwest into the Bay of Campeche over the next couple of days. After that, it remained mostly stationary just off the western coast of the Gulf of Mexico. On October 4, the system suddenly coalesced quickly around a nascent center of circulation. The next morning, it was designated Tropical Depression Fourteen.
The depression had low shear and warm water to work with and quickly strengthened into Tropical Storm Milton during the afternoon of the 5th. The system was rather small at first, but this allowed it to ramp up quickly, especially once an inner core became established early on October 6. Milton rapidly intensified into a hurricane that day. The system embarked on an unusual motion just south of east across the Gulf of Mexico. Overnight, the storm began a historic burst of strengthening. At 0900 UTC on October 7, the storm was upgraded to a category 2. Just two hours later it became a major hurricane, and after another two hours, a strong category 4. A little before 1600 UTC, it reached category 5 intensity. At 0000 UTC October 8, peaked at a historic intensity of 180 mph sustained winds and a central pressure of 897 mb. This was the lowest pressure recorded in an Atlantic hurricane since 2005 and made Milton the fifth most intense Atlantic hurricane on record by minimum pressure. The cyclone's ascent from tropical depression to category 5 hurricane took 49 hours, the fastest such a feat had ever been observed.
The storm remained incredibly compact throughout this explosion of intensification. A small but very symmetric eye had first appeared the morning of the 7th, and it contracted further after Milton reached category 5 strength until it was under 5 miles in diameter by that evening. The center was surrounded by an area of exceptionally cold cloud tops, the likes of which are seldom seen in the Atlantic basin. The storm's heading took it eastward across the Gulf just north of the Yucatan peninsula, and close enough to bring tropical storm conditions to the northern coastline. Overnight, Milton underwent an eyewall replacement cycle as the tiny eye filled in and the original eyewall was slowly replaced by a secondary larger one. This caused the storm's maximum winds to weaken back to category 4 and minimum pressure to rise temporarily, but it did expand the area of hurricane force winds.
The system recovered well on October 8 though and regained category 5 strength during the afternoon. By that time, Milton was on a faster east-northeastward path toward the central coast of western Florida. It reached an impressive secondary peak intensity of 165 mph winds and a minimum pressure of 902 mb that evening. Fortunately, shear began to increase quickly after that time and the cyclone weakened fairly rapidly from that point. It was down to a category 4 by early on the 9th, and became increasingly disheveled on satellite imagery. Nevertheless, Milton was still at category 3 strength when it made landfall in Florida that evening. The storm's days as a powerful hurricane led to significant storm surge impact, and its quick movement brought wind damage across a swath of the state. Milton was still a category 1 hurricane when it emerged on the Atlantic side of Florida early on October 10. By that time, the storm was interacting with a frontal zone and losing tropical characteristics. It became post-tropical early that evening and continued to gradually spin down as it pushed generally eastward out to sea.
The image above shows Milton near peak intensity on October 7. The cyclone exhibited a "pinhole eye" of only 5 miles across, a feature common for the Atlantic's top few strongest hurricanes. Milton's lowest pressure reading of 897 mb was the lowest observed in the Atlantic for 19 years.
Milton achieved category 5 status twice en route to a category 3 landfall in Florida.
Around the end of September, a tropical wave moving through the Caribbean interacted with a broad area of rotation over central America to produce a large area of disturbed weather. This disturbance moved northwest into the Bay of Campeche over the next couple of days. After that, it remained mostly stationary just off the western coast of the Gulf of Mexico. On October 4, the system suddenly coalesced quickly around a nascent center of circulation. The next morning, it was designated Tropical Depression Fourteen.
The depression had low shear and warm water to work with and quickly strengthened into Tropical Storm Milton during the afternoon of the 5th. The system was rather small at first, but this allowed it to ramp up quickly, especially once an inner core became established early on October 6. Milton rapidly intensified into a hurricane that day. The system embarked on an unusual motion just south of east across the Gulf of Mexico. Overnight, the storm began a historic burst of strengthening. At 0900 UTC on October 7, the storm was upgraded to a category 2. Just two hours later it became a major hurricane, and after another two hours, a strong category 4. A little before 1600 UTC, it reached category 5 intensity. At 0000 UTC October 8, peaked at a historic intensity of 180 mph sustained winds and a central pressure of 897 mb. This was the lowest pressure recorded in an Atlantic hurricane since 2005 and made Milton the fifth most intense Atlantic hurricane on record by minimum pressure. The cyclone's ascent from tropical depression to category 5 hurricane took 49 hours, the fastest such a feat had ever been observed.
The storm remained incredibly compact throughout this explosion of intensification. A small but very symmetric eye had first appeared the morning of the 7th, and it contracted further after Milton reached category 5 strength until it was under 5 miles in diameter by that evening. The center was surrounded by an area of exceptionally cold cloud tops, the likes of which are seldom seen in the Atlantic basin. The storm's heading took it eastward across the Gulf just north of the Yucatan peninsula, and close enough to bring tropical storm conditions to the northern coastline. Overnight, Milton underwent an eyewall replacement cycle as the tiny eye filled in and the original eyewall was slowly replaced by a secondary larger one. This caused the storm's maximum winds to weaken back to category 4 and minimum pressure to rise temporarily, but it did expand the area of hurricane force winds.
The system recovered well on October 8 though and regained category 5 strength during the afternoon. By that time, Milton was on a faster east-northeastward path toward the central coast of western Florida. It reached an impressive secondary peak intensity of 165 mph winds and a minimum pressure of 902 mb that evening. Fortunately, shear began to increase quickly after that time and the cyclone weakened fairly rapidly from that point. It was down to a category 4 by early on the 9th, and became increasingly disheveled on satellite imagery. Nevertheless, Milton was still at category 3 strength when it made landfall in Florida that evening. The storm's days as a powerful hurricane led to significant storm surge impact, and its quick movement brought wind damage across a swath of the state. Milton was still a category 1 hurricane when it emerged on the Atlantic side of Florida early on October 10. By that time, the storm was interacting with a frontal zone and losing tropical characteristics. It became post-tropical early that evening and continued to gradually spin down as it pushed generally eastward out to sea.
The image above shows Milton near peak intensity on October 7. The cyclone exhibited a "pinhole eye" of only 5 miles across, a feature common for the Atlantic's top few strongest hurricanes. Milton's lowest pressure reading of 897 mb was the lowest observed in the Atlantic for 19 years.
Milton achieved category 5 status twice en route to a category 3 landfall in Florida.
Friday, October 4, 2024
Hurricane Leslie (2024)
Storm Active: October 2-12
Near the end of September, a late season tropical wave entered the Atlantic, cruising slowly westward at a low latitude. The disturbance was dwarfed by the strengthening Tropical Storm (and soon Hurricane) Kirk to its northwest, but it still managed to steadily organize and become Tropical Depression Thirteen on October 2. The cyclone had plenty of moisture to work with, but was buffeted by the outflow of Kirk for another few days, so its intensification was gradual. Nevertheless, it strengthened into Tropical Storm Leslie that night and continued to improve its satellite presentation over the coming days.
The storm found a pocket of conditions favorable enough to reach hurricane strength late on October 4. Leslie surpassed nearby Kirk and again set the mark for easternmost formation of a hurricane in the tropical Atlantic post-September, at a longitude of 34.2° W, further evidence of the anomalous warmth of the Atlantic basin. Leslie turned west-northwest and then northwest over the next couple of days and encountered some mid-level try air. It had some success battling off this dry air intrusion for a time, and managed to intensify a bit more on October 6, reaching its first peak intensity of 90 mph winds and a pressure of 982 mb.
The next day, Leslie's structure began to slowly degrade. Although the storm was still producing very deep convection, the core became more lopsided and the maximum winds decreased. The system was downgraded to a tropical storm early on October 8. It rebuilt its eyewall and made a comeback later in the day however, regaining hurricane status. Leslie remained surprisingly resilient and deepened more on October 9. Its eye partially cleared out and it beat its previous strength mark that evening, reaching a new peak intensity as a category 2 hurricane with 105 mph winds and a central pressure of 972 mb.
Upper-level winds from a disturbance to the storm's west increased markedly over Leslie on the 10th, however. This initiated rapid weakening, an the storm also began curving north and then northeast out to sea. By October 11, the cyclone was down to moderate tropical storm strength and was producing convection only sporadically. The next day, Leslie dissipated altogether.
The image above shows Leslie near its second peak intensity as a category 2 hurricane on October 9.
Leslie did not affect land as a tropical cyclone.
Near the end of September, a late season tropical wave entered the Atlantic, cruising slowly westward at a low latitude. The disturbance was dwarfed by the strengthening Tropical Storm (and soon Hurricane) Kirk to its northwest, but it still managed to steadily organize and become Tropical Depression Thirteen on October 2. The cyclone had plenty of moisture to work with, but was buffeted by the outflow of Kirk for another few days, so its intensification was gradual. Nevertheless, it strengthened into Tropical Storm Leslie that night and continued to improve its satellite presentation over the coming days.
The storm found a pocket of conditions favorable enough to reach hurricane strength late on October 4. Leslie surpassed nearby Kirk and again set the mark for easternmost formation of a hurricane in the tropical Atlantic post-September, at a longitude of 34.2° W, further evidence of the anomalous warmth of the Atlantic basin. Leslie turned west-northwest and then northwest over the next couple of days and encountered some mid-level try air. It had some success battling off this dry air intrusion for a time, and managed to intensify a bit more on October 6, reaching its first peak intensity of 90 mph winds and a pressure of 982 mb.
The next day, Leslie's structure began to slowly degrade. Although the storm was still producing very deep convection, the core became more lopsided and the maximum winds decreased. The system was downgraded to a tropical storm early on October 8. It rebuilt its eyewall and made a comeback later in the day however, regaining hurricane status. Leslie remained surprisingly resilient and deepened more on October 9. Its eye partially cleared out and it beat its previous strength mark that evening, reaching a new peak intensity as a category 2 hurricane with 105 mph winds and a central pressure of 972 mb.
Upper-level winds from a disturbance to the storm's west increased markedly over Leslie on the 10th, however. This initiated rapid weakening, an the storm also began curving north and then northeast out to sea. By October 11, the cyclone was down to moderate tropical storm strength and was producing convection only sporadically. The next day, Leslie dissipated altogether.
The image above shows Leslie near its second peak intensity as a category 2 hurricane on October 9.
Leslie did not affect land as a tropical cyclone.
Sunday, September 29, 2024
Hurricane Kirk (2024)
Storm Active: September 29-October 7
Around September 25, a large tropical wave entered the Atlantic. After passing through the Cape Verde islands, the disturbance began more organized; it was classified Tropical Depression Twelve on September 29. The next day, it strengthened into Tropical Storm Kirk. The storm was moving west at first, but soon began to arc very gradually toward the north. Kirk was a sprawling storm and was a little disheveled on satellite imagery due to some wind shear, but it nevertheless intensified steadily. On October 1, it became a hurricane. Kirk was located at 40.1° W when it reached hurricane strength, far surpassing the previous record easternmost tropical Atlantic hurricane formation in October (a record previously shared by Jose of 1999 and Tammy of 2023). That record stood for all of three days until it was again far surpassed by Hurricane Leslie.
Kirk didn't stop there, however. The large hurricane deepened much further over the following days, especially during a rapid burst of intensification beginning on the evening of October 2, when the eye quickly cleared on satellite imagery and became a major hurricane. The following afternoon, it reached category 4, and late on October 3, Kirk achieved a powerful peak intensity of 145 mph winds and a central pressure of 934 mb. The next day, the storm's steady northwest heading brought it into an area of higher shear from an upper-level low to the northwest. A gradual weakening trend began. The storm turned north and began to accelerate as it felt the tug of the mid-latitude westerlies.
Even as the core lost its definition and the peak winds decreased, Kirk's windfield grew as it gained latitude, pushing large waves to coasts all around the Atlantic. It lost major hurricane status on October 6 and turned northeast. Increasingly hostile upper-level winds soon began extratropical transition. The storm became post-tropical during the morning of October 7. What was left of Kirk eventually brought rain and strong winds to parts of western Europe a few days later.
The image above shows Kirk as a category 4 hurricane over the open Atlantic on September 4.
Despite being a large hurricane, Kirk did not directly affect land as a tropical cyclone.
Around September 25, a large tropical wave entered the Atlantic. After passing through the Cape Verde islands, the disturbance began more organized; it was classified Tropical Depression Twelve on September 29. The next day, it strengthened into Tropical Storm Kirk. The storm was moving west at first, but soon began to arc very gradually toward the north. Kirk was a sprawling storm and was a little disheveled on satellite imagery due to some wind shear, but it nevertheless intensified steadily. On October 1, it became a hurricane. Kirk was located at 40.1° W when it reached hurricane strength, far surpassing the previous record easternmost tropical Atlantic hurricane formation in October (a record previously shared by Jose of 1999 and Tammy of 2023). That record stood for all of three days until it was again far surpassed by Hurricane Leslie.
Kirk didn't stop there, however. The large hurricane deepened much further over the following days, especially during a rapid burst of intensification beginning on the evening of October 2, when the eye quickly cleared on satellite imagery and became a major hurricane. The following afternoon, it reached category 4, and late on October 3, Kirk achieved a powerful peak intensity of 145 mph winds and a central pressure of 934 mb. The next day, the storm's steady northwest heading brought it into an area of higher shear from an upper-level low to the northwest. A gradual weakening trend began. The storm turned north and began to accelerate as it felt the tug of the mid-latitude westerlies.
Even as the core lost its definition and the peak winds decreased, Kirk's windfield grew as it gained latitude, pushing large waves to coasts all around the Atlantic. It lost major hurricane status on October 6 and turned northeast. Increasingly hostile upper-level winds soon began extratropical transition. The storm became post-tropical during the morning of October 7. What was left of Kirk eventually brought rain and strong winds to parts of western Europe a few days later.
The image above shows Kirk as a category 4 hurricane over the open Atlantic on September 4.
Despite being a large hurricane, Kirk did not directly affect land as a tropical cyclone.
Friday, September 27, 2024
Tropical Storm Joyce (2024)
Storm Active: September 27-30
On September 22, another tropical wave left Africa and entered the eastern tropical Atlantic. Within a few days, the disturbance was close to tropical storm status, but the center was not well-defined enough. It took a few more days for the system to clear the final hurdle and become Tropical Storm Joyce on September 27, when it was located around halfway between Africa and the Leeward Islands. Joyce intensified modestly in the day after its formation and turned northwest into a weakness in the subtropical ridge. However, the system soon encountered increasing wind shear and began to weaken by September 29.
Late that same day, it weakened to a tropical depression. Though the storm continued to produce bursts of thunderstorm activity, the center became less and less defined and eventually dissipated late on September 30.
Joyce was a small tropical storm; the image above shows a satellite image from September 27.
Joyce was a short-lived tropical storm that did not affect any land areas.
On September 22, another tropical wave left Africa and entered the eastern tropical Atlantic. Within a few days, the disturbance was close to tropical storm status, but the center was not well-defined enough. It took a few more days for the system to clear the final hurdle and become Tropical Storm Joyce on September 27, when it was located around halfway between Africa and the Leeward Islands. Joyce intensified modestly in the day after its formation and turned northwest into a weakness in the subtropical ridge. However, the system soon encountered increasing wind shear and began to weaken by September 29.
Late that same day, it weakened to a tropical depression. Though the storm continued to produce bursts of thunderstorm activity, the center became less and less defined and eventually dissipated late on September 30.
Joyce was a small tropical storm; the image above shows a satellite image from September 27.
Joyce was a short-lived tropical storm that did not affect any land areas.
Hurricane Isaac (2024)
Storm Active: September 25-30
Around September 20, a frontal boundary moved into eastward into the Atlantic ocean from North America. A well-defined non-tropical low formed along the boundary and passed north of Bermuda on September 23. Deep convection increased near the center over the next couple of days and the circulation separated from the front. The system was named Tropical Storm Isaac late on September 25 over the central tropical Atlantic.
Isaac rode the clockwise flow east-northeast around the north side of the subtropical ridge and encountered enough upper-level divergence and instability to support strengthening even over marginally warm sea surface temperatures. The storm reached hurricane status early on the 27th and an eye began to intermittently appear on satellite imagery.
Surprisingly, Isaac had a few more tricks up its sleeve, and intensified even further overnight. The eye became better defined and the surrounding area of convection larger and deeper. The storm peaked at category 2 strength on September 28 with peak winds of 105 mph and a central pressure of 968 mb. It turned northeast and began to pass over markedly colder water soon after. This began a period of gradual weakening, which brought Isaac back down to tropical storm strength by the evening of September 29, when it was passing northwest of the Azores. Beyond rough seas, there was no direct impact to the islands. Cold water and increasing shear brought about Isaac's transition to a post-tropical cyclone on September 30. The remnants continued northeastward until they dissipated west of Ireland.
The image above shows Isaac as a category 2 hurricane.
Isaac was impressively strong for its latitude, but did not affect any land areas.
Around September 20, a frontal boundary moved into eastward into the Atlantic ocean from North America. A well-defined non-tropical low formed along the boundary and passed north of Bermuda on September 23. Deep convection increased near the center over the next couple of days and the circulation separated from the front. The system was named Tropical Storm Isaac late on September 25 over the central tropical Atlantic.
Isaac rode the clockwise flow east-northeast around the north side of the subtropical ridge and encountered enough upper-level divergence and instability to support strengthening even over marginally warm sea surface temperatures. The storm reached hurricane status early on the 27th and an eye began to intermittently appear on satellite imagery.
Surprisingly, Isaac had a few more tricks up its sleeve, and intensified even further overnight. The eye became better defined and the surrounding area of convection larger and deeper. The storm peaked at category 2 strength on September 28 with peak winds of 105 mph and a central pressure of 968 mb. It turned northeast and began to pass over markedly colder water soon after. This began a period of gradual weakening, which brought Isaac back down to tropical storm strength by the evening of September 29, when it was passing northwest of the Azores. Beyond rough seas, there was no direct impact to the islands. Cold water and increasing shear brought about Isaac's transition to a post-tropical cyclone on September 30. The remnants continued northeastward until they dissipated west of Ireland.
The image above shows Isaac as a category 2 hurricane.
Isaac was impressively strong for its latitude, but did not affect any land areas.
Tuesday, September 24, 2024
Hurricane Helene (2024)
Storm Active: September 24-27
A large area of low pressure developed just east of central American around September 22. The sprawling system drifted generally northward, but the counterclockwise flow brought extreme rains especially to the Pacific coasts of Nicaragua, Honduras, and El Salvador. The next day, the disturbance began to organize over the eastern Caribbean, but lacked a defined center. On the 24th, it became organized enough to be named Tropical Storm Helene.
When Helene formed, its center was exposed to the west of the main convective mass due to some shear out of the southwest. However, this shear was already diminishing; high oceanic heat content and atmospheric humidity soon put the storm on a strengthening trend as it moved northwestward. Helene was a large storm, with gale force radii above the 90th percentile of historical Atlantic cyclones at the same latitude. As a result, the core was slow to consolidate, but impacts were very widespread. When the storm passed just west of the northeast tip of the Yucatan Peninsula during the morning of September 25, tropical storm force winds already extended more than 250 miles from the center in some directions. Around the same time, Helene strengthened into a hurricane.
The hurricane began to feel the flow ahead of a trough over the central United States later that day and accelerated toward the north, entering the Gulf of Mexico. Overnight, the core of Helene steadily became better defined and an eye began to emerge. Once the eyewall was well-established, the intensification accelerated on September 26. The storm reached category 2 that morning and became a major hurricane that afternoon. By the early evening, Helene's forward speed had increased to more than 20 mph toward the north-northeast and it was closing in quickly on the Gulf coast. It reached category 4 soon after, reaching a peak intensity of 140 mph winds and a central pressure of 938 mb at landfall in the big bend region of Florida late on September 26, local time.
The large size and fast motion of the storm meant that the storm surge impacts to the concave area of coastline were very severe. On top of that, hurricane-force winds spread far inland and into Georgia before the storm could spin down significantly. The wind damage was severe for a large swath of the southeast, especially just east of the center's path. Helene weakened to a tropical storm over central Georgia and only lost tropical storm status over Tennessee during the afternoon of the 27th; the cyclone became post-tropical that evening. Its remnants slowed to a standstill near the Tennessee valley and slowly diminished, but the combination of Helene-influenced rains before the arrival of the storm and ex-Helene stalling over the area led to some of the storm's heaviest rainfall amounts in the region, especially western North Carolina. What was left of the hurricane finally dissipated by early on September 29.
The image above is a nighttime infrared satellite view of Hurricane Helene at peak intensity as a category 4 hurricane just before its landfall in Florida. The storm's uncommonly large windfield caused widespread damage.
Helene was a relatively short-lived but large and devastating storm.
A large area of low pressure developed just east of central American around September 22. The sprawling system drifted generally northward, but the counterclockwise flow brought extreme rains especially to the Pacific coasts of Nicaragua, Honduras, and El Salvador. The next day, the disturbance began to organize over the eastern Caribbean, but lacked a defined center. On the 24th, it became organized enough to be named Tropical Storm Helene.
When Helene formed, its center was exposed to the west of the main convective mass due to some shear out of the southwest. However, this shear was already diminishing; high oceanic heat content and atmospheric humidity soon put the storm on a strengthening trend as it moved northwestward. Helene was a large storm, with gale force radii above the 90th percentile of historical Atlantic cyclones at the same latitude. As a result, the core was slow to consolidate, but impacts were very widespread. When the storm passed just west of the northeast tip of the Yucatan Peninsula during the morning of September 25, tropical storm force winds already extended more than 250 miles from the center in some directions. Around the same time, Helene strengthened into a hurricane.
The hurricane began to feel the flow ahead of a trough over the central United States later that day and accelerated toward the north, entering the Gulf of Mexico. Overnight, the core of Helene steadily became better defined and an eye began to emerge. Once the eyewall was well-established, the intensification accelerated on September 26. The storm reached category 2 that morning and became a major hurricane that afternoon. By the early evening, Helene's forward speed had increased to more than 20 mph toward the north-northeast and it was closing in quickly on the Gulf coast. It reached category 4 soon after, reaching a peak intensity of 140 mph winds and a central pressure of 938 mb at landfall in the big bend region of Florida late on September 26, local time.
The large size and fast motion of the storm meant that the storm surge impacts to the concave area of coastline were very severe. On top of that, hurricane-force winds spread far inland and into Georgia before the storm could spin down significantly. The wind damage was severe for a large swath of the southeast, especially just east of the center's path. Helene weakened to a tropical storm over central Georgia and only lost tropical storm status over Tennessee during the afternoon of the 27th; the cyclone became post-tropical that evening. Its remnants slowed to a standstill near the Tennessee valley and slowly diminished, but the combination of Helene-influenced rains before the arrival of the storm and ex-Helene stalling over the area led to some of the storm's heaviest rainfall amounts in the region, especially western North Carolina. What was left of the hurricane finally dissipated by early on September 29.
The image above is a nighttime infrared satellite view of Hurricane Helene at peak intensity as a category 4 hurricane just before its landfall in Florida. The storm's uncommonly large windfield caused widespread damage.
Helene was a relatively short-lived but large and devastating storm.
Wednesday, September 11, 2024
Tropical Storm Gordon (2024)
Storm Active: September 11-17
A disturbance over the eastern Atlantic crossed the Cabo Verde Islands around September 10, bringing scattered rains to the islands. The next day, the system developed a closed circulation and was classified Tropical Depression Seven. The cyclone was small, with little in the way of thunderstorm activity, and organized only slowly as it moved steadily west-northwest. It wasn't until early on September 13 that it strengthened into Tropical Storm Gordon. Convection had increased with the storm, but was slightly displaced from the center by moderate wind shear out of the west. As a result, the cyclone did not manage to strengthen much, and reached peak winds of 45 mph on September 14.
Gordon entered a drier air mass shortly thereafter and began weakening again as it slowed down and turned slightly south of west under the influence of a ridge of high pressure. It became a tropical depression on September 15. Though weakening temporarily halted that evening, Gordon was never able to fully recover. Thunderstorm activity became more and more diffuse, and the center became less defined until it dissipated altogether on September 17.
The image above shows Gordon just after it was named.
Gordon was stifled by wind shear and dry air as it crossed the central tropical Atlantic.
A disturbance over the eastern Atlantic crossed the Cabo Verde Islands around September 10, bringing scattered rains to the islands. The next day, the system developed a closed circulation and was classified Tropical Depression Seven. The cyclone was small, with little in the way of thunderstorm activity, and organized only slowly as it moved steadily west-northwest. It wasn't until early on September 13 that it strengthened into Tropical Storm Gordon. Convection had increased with the storm, but was slightly displaced from the center by moderate wind shear out of the west. As a result, the cyclone did not manage to strengthen much, and reached peak winds of 45 mph on September 14.
Gordon entered a drier air mass shortly thereafter and began weakening again as it slowed down and turned slightly south of west under the influence of a ridge of high pressure. It became a tropical depression on September 15. Though weakening temporarily halted that evening, Gordon was never able to fully recover. Thunderstorm activity became more and more diffuse, and the center became less defined until it dissipated altogether on September 17.
The image above shows Gordon just after it was named.
Gordon was stifled by wind shear and dry air as it crossed the central tropical Atlantic.
Monday, September 9, 2024
Hurricane Francine (2024)
Storm Active: September 9-13
A tropical wave crossed the Atlantic Ocean during the last week of August without developing significantly. It made its way across the Caribbean and the Yucatan Peninsula before finally showing signs of organization in the Bay of Campeche a week into September. When the disturbance first entered the bay on the 7th, it was interacting with a cold front, and the area of low pressure was poorly defined. The system was producing vigorous storm activity though, and by the next day was also generating sustained winds to gale force. The inner structure of the disturbance improved markedly during the morning of September 9 and it was named Tropical Storm Francine.
The storm moved slowly northwest that day around the periphery of a ridge centered over Cuba. It took advantage of the warm waters of the Gulf of Mexico and began to strengthen. That night, an intrusion of dry air caused the core convection to collapse and temporarily hindered intensification. Deepening resumed the next morning and Francine turned toward the northeast as it began to feel the approach of a trough from the northwest. The evening of the 10th, the storm was upgraded to a category 1 hurricane. The storm accelerated toward the northeast overnight and wind shear began to increase as the storm neared the Louisiana coastline. As a result, the core took on a somewhat lopsided appearance. Nevertheless, Francine reached a peak category 2 intensity of 100 mph winds and a central pressure of 972 mb that afternoon just before landfall in central Louisiana.
Once inland, the storm rapidly weakened. It weakened to a tropical depression on September 12 over Mississippi and became post-tropical that afternoon. After that, the remnants slowed down and moved erratically across the interior southeast. This brought a sustained period of heavy rain to the region, especially northern Mississippi, until dissipation occurred a few days after.
The image above shows Francine just before landfall.
Francine's impacts were mitigated by the fact that it made landfall in a sparsely populated region and weakened quickly after landfall.
A tropical wave crossed the Atlantic Ocean during the last week of August without developing significantly. It made its way across the Caribbean and the Yucatan Peninsula before finally showing signs of organization in the Bay of Campeche a week into September. When the disturbance first entered the bay on the 7th, it was interacting with a cold front, and the area of low pressure was poorly defined. The system was producing vigorous storm activity though, and by the next day was also generating sustained winds to gale force. The inner structure of the disturbance improved markedly during the morning of September 9 and it was named Tropical Storm Francine.
The storm moved slowly northwest that day around the periphery of a ridge centered over Cuba. It took advantage of the warm waters of the Gulf of Mexico and began to strengthen. That night, an intrusion of dry air caused the core convection to collapse and temporarily hindered intensification. Deepening resumed the next morning and Francine turned toward the northeast as it began to feel the approach of a trough from the northwest. The evening of the 10th, the storm was upgraded to a category 1 hurricane. The storm accelerated toward the northeast overnight and wind shear began to increase as the storm neared the Louisiana coastline. As a result, the core took on a somewhat lopsided appearance. Nevertheless, Francine reached a peak category 2 intensity of 100 mph winds and a central pressure of 972 mb that afternoon just before landfall in central Louisiana.
Once inland, the storm rapidly weakened. It weakened to a tropical depression on September 12 over Mississippi and became post-tropical that afternoon. After that, the remnants slowed down and moved erratically across the interior southeast. This brought a sustained period of heavy rain to the region, especially northern Mississippi, until dissipation occurred a few days after.
The image above shows Francine just before landfall.
Francine's impacts were mitigated by the fact that it made landfall in a sparsely populated region and weakened quickly after landfall.
Monday, August 12, 2024
Hurricane Ernesto (2024)
Storm Active: August 12-20
During the second week of August, a tropical wave traversed the tropical Atlantic. Dry air near the wave limited its shower activity, so not much development occurred at first. Some spin became evident on satellite imagery around August 11, but convection remained very limited until the next day. During the afternoon of August 12, the system acquired a well-defined center and was designated Tropical Storm Ernesto a few hundred miles east of the Leeward Islands. Newly-formed Ernesto was moving at an extremely fast forward speed of 28 mph. On that heading, it quickly approached the Caribbean and the center passed near the island of Guadeloupe early on August 13.
Considering the struggles its precursor tropical wave had, Ernesto's transformation on the 12th and the 13th was extraordinary: the storm ballooned in size and developed large and pronounced banding features which brought heavy rains to locations hundreds of miles from the center. The organization of the core lagged a little behind but the cyclone nevertheless began to intensify steadily as it moved west-northwest through the northeast corner of the Caribbean. Ernesto was a strong tropical storm by the time it passed among the Virgin Islands that evening. Shortly after, the center of circulation emerged into the Atlantic, but a large blob of convection associated with the system persisted for the next day well to the south. This brought further heavy rain to Puerto Rico and neighboring areas.
During the morning of August 14, Ernesto strengthened into a hurricane. A trough of low pressure over the subtropical Atlantic turned the storm to the right throughout the day. Soon, the storm was headed north-northeast toward Bermuda. It underwent some structural changes too: periodic dry air intrusions prevented Ernesto from completing an eyewall, but lent the cyclone an spiral satellite apperance on the 15th. The radii of gale force winds also increased significantly in size and the pressure dropped. Hence even though conditions weren't ideal, the warm water and atmospheric instability helped Ernesto to reach category 2 hurricane strength by that evening. The storm peaked at 100 moh sustained winds and a central pressure of 969 mb as it approached Bermuda.
The trough that was steering Ernesto exited to the northeast by the 16th without fully capturing the cyclone. This slowed the storm's forward speed significantly. At the same time, wind shear increased markedly that day and pushed more dry air into the center of Ernesto. This weakened the storm, but it was still a category 1 hurricane when it made a direct landfall in Bermuda early on August 17. It moved quite slowly past the island, leading to a prolonged period of gale force winds. Early on the 18th, Ernesto was finally leaving the island behind and it weakened to a tropical storm. The cyclone found a pocket of more favorable conditions farther north and reintensified to a hurricane that day as a ragged eye appeared on satellite. A second trough arrived at the U.S. east coast to give Ernesto its final boost out to sea and the storm began accelerating toward the northeast. It stayed over the Gulf Stream waters long enough to reach a secondary peak intensity of 90 mph winds and a pressure of 968 mb during the morning of August 19. Late that day, though, it crossed the northern wall of the warm current and sea surface temperatures underneath Ernesto plummeted. The cyclone began to weaken and begin extratropical transition. However, it was still a hurricane when it passed just southeast of Newfoundland late the same evening, bringing gale force winds to the nearest corner of the island. Ernesto became post-tropical during the morning of August 20. The system moved quickly northeast across the Atlantic and impacted the UK a few days later.
The image above shows Ernesto as a category 2 hurricane on August 16 approaching Bermuda from the southeast.
Ernesto moved through the northeast Caribbean before making a direct landfall in Bermuda.
During the second week of August, a tropical wave traversed the tropical Atlantic. Dry air near the wave limited its shower activity, so not much development occurred at first. Some spin became evident on satellite imagery around August 11, but convection remained very limited until the next day. During the afternoon of August 12, the system acquired a well-defined center and was designated Tropical Storm Ernesto a few hundred miles east of the Leeward Islands. Newly-formed Ernesto was moving at an extremely fast forward speed of 28 mph. On that heading, it quickly approached the Caribbean and the center passed near the island of Guadeloupe early on August 13.
Considering the struggles its precursor tropical wave had, Ernesto's transformation on the 12th and the 13th was extraordinary: the storm ballooned in size and developed large and pronounced banding features which brought heavy rains to locations hundreds of miles from the center. The organization of the core lagged a little behind but the cyclone nevertheless began to intensify steadily as it moved west-northwest through the northeast corner of the Caribbean. Ernesto was a strong tropical storm by the time it passed among the Virgin Islands that evening. Shortly after, the center of circulation emerged into the Atlantic, but a large blob of convection associated with the system persisted for the next day well to the south. This brought further heavy rain to Puerto Rico and neighboring areas.
During the morning of August 14, Ernesto strengthened into a hurricane. A trough of low pressure over the subtropical Atlantic turned the storm to the right throughout the day. Soon, the storm was headed north-northeast toward Bermuda. It underwent some structural changes too: periodic dry air intrusions prevented Ernesto from completing an eyewall, but lent the cyclone an spiral satellite apperance on the 15th. The radii of gale force winds also increased significantly in size and the pressure dropped. Hence even though conditions weren't ideal, the warm water and atmospheric instability helped Ernesto to reach category 2 hurricane strength by that evening. The storm peaked at 100 moh sustained winds and a central pressure of 969 mb as it approached Bermuda.
The trough that was steering Ernesto exited to the northeast by the 16th without fully capturing the cyclone. This slowed the storm's forward speed significantly. At the same time, wind shear increased markedly that day and pushed more dry air into the center of Ernesto. This weakened the storm, but it was still a category 1 hurricane when it made a direct landfall in Bermuda early on August 17. It moved quite slowly past the island, leading to a prolonged period of gale force winds. Early on the 18th, Ernesto was finally leaving the island behind and it weakened to a tropical storm. The cyclone found a pocket of more favorable conditions farther north and reintensified to a hurricane that day as a ragged eye appeared on satellite. A second trough arrived at the U.S. east coast to give Ernesto its final boost out to sea and the storm began accelerating toward the northeast. It stayed over the Gulf Stream waters long enough to reach a secondary peak intensity of 90 mph winds and a pressure of 968 mb during the morning of August 19. Late that day, though, it crossed the northern wall of the warm current and sea surface temperatures underneath Ernesto plummeted. The cyclone began to weaken and begin extratropical transition. However, it was still a hurricane when it passed just southeast of Newfoundland late the same evening, bringing gale force winds to the nearest corner of the island. Ernesto became post-tropical during the morning of August 20. The system moved quickly northeast across the Atlantic and impacted the UK a few days later.
The image above shows Ernesto as a category 2 hurricane on August 16 approaching Bermuda from the southeast.
Ernesto moved through the northeast Caribbean before making a direct landfall in Bermuda.
Saturday, August 3, 2024
Hurricane Debby (2024)
Storm Active: August 2-9
During the last week of July, a tropical wave crossed the tropical Atlantic and moved along the northern Caribbean islands. For much of that journey, dry air stifled its development, but by August 1 it was starting to show some more signs of organization. The disturbance passed over Hispaniola and Cuba, bringing heavy rainfall. The land interaction slowed development a bit longer, but the system found a window to consolidate south of central Cuba later on August 2 and was classified Tropical Depression Four. The storm was initially steered west-northwest by a strong subtropical ridge, but a weakness over the eastern U.S. gave it the opportunity to turn northwest on August 3. The center passed over western Cuba that morning.
That evening, the cyclone emerged into the Gulf of Mexico. It found a much more humid atmosphere and low wind shear, which allowed the system to begin strengthening and become Tropical Storm Debby that evening. Thunderstorm activity began to build near the center of circulation early on August 4. Radar imagery also showed an eyewall building throughout the day as Debby paralleled the coastline of western Florida. The storm then turned north-northeast overnight and reached category 1 hurricane strength. It made landfall in the Big Bend of Florida during the morning of August 5 at its peak intensity of 80 mph winds and a central pressure of 979 mb.
Debby entered an area of weak steering currents and slowed down that day as it moved farther inland. Its winds diminished and the inner core decayed that evening as the cyclone was cut off from energy from the ocean. Nevertheless, a severe flooding event began to unfold for the southeast U.S. due to the slow movement of the storm. The center crossed Georgia and emerged over the Atlantic near the Georgia-South Carolina border during the afternoon of August 6. At the time, it was still hanging on to minimal tropical storm intensity. Though it moved over water, the storm did not travel eastward far enough to find the highest oceanic heat content of the region in the Gulf stream. As a result, the circulation remained mostly devoid of convection near the center and only gradually built back outer bands on August 7. It also underwent modest deepening, but did not much resemble a typical tropical storm. A rebuilding ridge to Debby's east began to push it back to the west of north that evening and made landfall in northern South Carolina overnight.
The storm's rains spread northward as it weakened inland on August 8. Late that afternoon, it weakened to a tropical depression. By early the next morning, the system became post-tropical over Virginia. The remnants of Debby sped off to the northeast and brought additional rain to the mid-Atlantic and regions farther north over the next couple of days.
The image above shows Debby at peak intensity as a category 1 hurricane in the early morning hours of August 5, just before Florida landfall.
Debby's slow movement across the U.S. southeast brought large rainfall totals, though flooding impacts were not as severe as initially feared.
During the last week of July, a tropical wave crossed the tropical Atlantic and moved along the northern Caribbean islands. For much of that journey, dry air stifled its development, but by August 1 it was starting to show some more signs of organization. The disturbance passed over Hispaniola and Cuba, bringing heavy rainfall. The land interaction slowed development a bit longer, but the system found a window to consolidate south of central Cuba later on August 2 and was classified Tropical Depression Four. The storm was initially steered west-northwest by a strong subtropical ridge, but a weakness over the eastern U.S. gave it the opportunity to turn northwest on August 3. The center passed over western Cuba that morning.
That evening, the cyclone emerged into the Gulf of Mexico. It found a much more humid atmosphere and low wind shear, which allowed the system to begin strengthening and become Tropical Storm Debby that evening. Thunderstorm activity began to build near the center of circulation early on August 4. Radar imagery also showed an eyewall building throughout the day as Debby paralleled the coastline of western Florida. The storm then turned north-northeast overnight and reached category 1 hurricane strength. It made landfall in the Big Bend of Florida during the morning of August 5 at its peak intensity of 80 mph winds and a central pressure of 979 mb.
Debby entered an area of weak steering currents and slowed down that day as it moved farther inland. Its winds diminished and the inner core decayed that evening as the cyclone was cut off from energy from the ocean. Nevertheless, a severe flooding event began to unfold for the southeast U.S. due to the slow movement of the storm. The center crossed Georgia and emerged over the Atlantic near the Georgia-South Carolina border during the afternoon of August 6. At the time, it was still hanging on to minimal tropical storm intensity. Though it moved over water, the storm did not travel eastward far enough to find the highest oceanic heat content of the region in the Gulf stream. As a result, the circulation remained mostly devoid of convection near the center and only gradually built back outer bands on August 7. It also underwent modest deepening, but did not much resemble a typical tropical storm. A rebuilding ridge to Debby's east began to push it back to the west of north that evening and made landfall in northern South Carolina overnight.
The storm's rains spread northward as it weakened inland on August 8. Late that afternoon, it weakened to a tropical depression. By early the next morning, the system became post-tropical over Virginia. The remnants of Debby sped off to the northeast and brought additional rain to the mid-Atlantic and regions farther north over the next couple of days.
The image above shows Debby at peak intensity as a category 1 hurricane in the early morning hours of August 5, just before Florida landfall.
Debby's slow movement across the U.S. southeast brought large rainfall totals, though flooding impacts were not as severe as initially feared.
Monday, July 1, 2024
Tropical Storm Chris (2024)
Storm Active: June 30-July 1
A tropical wave crossed the tropical Atlantic and reached the Caribbean on June 25. It remained quite far south, embedded in the Intertropical Convergence Zone, and so did not exhibit any signs of development until arriving in the western Caribbean a few days later. By June 28, the disturbance was creating a large area of scattered thunderstorms near the Yucatan Peninsula and the waters to the west, but lacked any discernible center of circulation. From there, the system's west-northwestward trajectory brought it across the peninsula, preventing further organization until it reached the Bay of Campeche. There, the system found a short window of opportunity to acquire a closed center and it was designated Tropical Depression Three on June 30.
The storm's circulation was fairly broad and the associated convection diffuse, but aircraft reconaissance to the cyclone found evidence for gale force winds that evening, prompting an upgrade to Tropical Storm Chris. Very soon after the upgrade, Chris made landfall in Mexico in the state of Veracruz, south of where Tropical Storm Alberto had ten days earlier. The system rapidly weakened once inland, with the main threat being flooding rains. Chris dissipated by late morning on July 1.
The image above shows Tropical Depression Three on June 30, just before it was named. The center was already very close to the coastline of Mexico.
Chris had a very short lifetime as a tropical cyclone (circular points), but originated from a tropical wave that brought disturbed weather across the entire Caribbean.
A tropical wave crossed the tropical Atlantic and reached the Caribbean on June 25. It remained quite far south, embedded in the Intertropical Convergence Zone, and so did not exhibit any signs of development until arriving in the western Caribbean a few days later. By June 28, the disturbance was creating a large area of scattered thunderstorms near the Yucatan Peninsula and the waters to the west, but lacked any discernible center of circulation. From there, the system's west-northwestward trajectory brought it across the peninsula, preventing further organization until it reached the Bay of Campeche. There, the system found a short window of opportunity to acquire a closed center and it was designated Tropical Depression Three on June 30.
The storm's circulation was fairly broad and the associated convection diffuse, but aircraft reconaissance to the cyclone found evidence for gale force winds that evening, prompting an upgrade to Tropical Storm Chris. Very soon after the upgrade, Chris made landfall in Mexico in the state of Veracruz, south of where Tropical Storm Alberto had ten days earlier. The system rapidly weakened once inland, with the main threat being flooding rains. Chris dissipated by late morning on July 1.
The image above shows Tropical Depression Three on June 30, just before it was named. The center was already very close to the coastline of Mexico.
Chris had a very short lifetime as a tropical cyclone (circular points), but originated from a tropical wave that brought disturbed weather across the entire Caribbean.
Friday, June 28, 2024
Hurricane Beryl (2024)
Storm Active: June 28-July 9
On June 23, a tropical wave moved over the tropical Atlantic from the western coast of Africa. The wave encountered unusually warm water and moist air for June, which allowed it to gradually develop as it moved fairly quickly westward at 15-20 mph. By June 27, a broad low pressure center had formed and a nascent circulation was evident on satellite imagery. Convection increased near the center the next day and the system was designated Tropical Depression Two. This marked the easternmost June formation of an Atlantic tropical cyclone in over 20 years.
Later that evening, the depression was upgraded to Tropical Storm Beryl. From that point, Beryl underwent rapid intensification for the next few days, exhibiting the textbook evolution of a strengthening tropical cyclone. At first an amorphous blob of thunderstorms, Beryl developed pronounced spiral bands fanning out west of the circulation center early on the 29th. By that afternoon, a central dense overcast covered the center and the system began building an eyewall. Beryl was upgraded to a hurricane that evening. To that point, conditions near the storm were quick favorable to intensification with the exception of some wind shear from the east. However, since the shear vector pointed the same direction as the storm's motion, it had less of an effect than it otherwise would. Even the shear diminished by early on June 30, however. Beryl's burst of strengthening continued and it became the first major hurricane of the 2024 Atlantic hurricane season that morning as an eye emerged on satellite. At the time it reached category 3, it was located at 10.6° N, which was farther south than any major hurricane had ever been observed in the Atlantic, with the lone exception of Hurricane Ivan in 2004, which did the same at 10.2° N.
The eye cleared out further over the next few hours and Beryl reached category 4 strength, with peak winds of 130 mph. Beryl was the first Atlantic hurricane ever recorded to reach category 4 intensity in June; the previous earliest category 4 in a season was Hurricane Dennis of 2005, which reached that intensity on July 8. By that time, the storm was approaching the Windward islands, still moving at a fairly rapid clip just north of west. The eye contracted and clouded over during the night as the core of Beryl underwent an eyewall replacement cycle. This reduced the maximum winds back to category 3 intensity but broadened the windfield. A new larger eye cleared out during the morning of July 1 and the storm resumed intensification, regaining category 4 strength. That morning, Beryl made a direct landfall in the island of Carriacou, part of the Grenadine island chain in the Windward Islands, with maximum sustained winds of 150 mph and a minimum pressure of 950 mb. The cyclone was the first known major hurricane to directly hit any of the Grenadine Islands.
Beryl continued quickly toward the west-northwest and entered the Caribbean sea that afternoon. Ocean heat content was even higher in this region, and atmospheric conditions remained favorable, so the storm deepened even further as it left the Windward Islands behind. That night, it reached category 5. Beryl eclipsed Hurricane Emily of 2005 to become the earliest category 5 on record (Emily reached this category on July 16), and was only the second recorded category 5 in July. The hurricane reached its peak intensity of 165 mph winds and a pressure of 934 mb early in the morning on July 2. After that, wind shear began to increase, disrupting Beryl. Throughout the day, the circulation became somewhat tilted toward the northeast with height and the eye lost definition until it became cloud-filled; the satellite presentation also became much less symmetric. Despite all this, the system weakened only slowly: it was reduced to category 4 during the afternoon of July 2, but maintained category 4 intensity through July 3.
Beryl's center passed just south of Jamaica during the day, but close enough that the northern eyewall crossed the coastal areas of the southwestern portion of the island. The northern eyewall had the strongest winds, so the impacts were fairly severe despite the lack of an official landfall. This land interaction and still increasing shear brought the system down to category 3 intensity overnight, but the inner core was surprisingly resilient, with at least the northern eyewall remaining intact into July 4. That morning, the storm passed south of Grand Cayman of the Cayman Islands, still a major hurricane; the center was a little further away, so the island was not affected as much as Jamaica.
The storm diminished to a category 2 that afternoon, but unexpectedly halted its weakening trend and fluctuated in strength later that day. Its continued west-northwesterly motion brought it toward the Yucatan Peninsula overnight and Beryl made landfall near Tulum as a category 2 during the morning of July 5. Fortunately, the storm started weakening again immediately prior to landfall and the windfield contracted some, limiting impacts. The cyclone's passage over the Yucatan Peninsula finally damaged it more significantly: the vortex became tilted with height and all deep convection was gone from the center by the time it emerged into the Gulf of Mexico that evening. At that time, Beryl's winds had fallen to tropical storm force. The Gulf waters, particularly immediately northwest of Yucatan, did not have as much heat content as the Caribbean Beryl had just left; further, some dry air from the southwest had been entrained into the circulation. Therefore, even once over water it took time for the system to recuperate. Strong thunderstorm activity only began to return in earnest around 12 hours after it emerged over water, during the morning of July 6.
Beryl began to feel the influence of a trough of low pressure over the central United States and it curved toward the northwest that day. The storm's battle with dry air greatly slowed intensification, though some deepening began on July 7. That night, the system approached the Texas coastline, but found more favorable conditions in its last hours over water. Beryl regained hurricane intensity and made landfall in Texas early on July 8th with peak sustained winds of 80 mph and a minimum central pressure of 979 mb. Though the cyclone was only a category 1, the curvature of the Texas coastline amplified storm surge impacts, and the storm held its own a fair way inland, bringing hurricane force winds to the Houston area.
Beryl gradually weakened as it pushed farther inland on the 8th and curved toward the northeast. The cyclone diminished to a tropical storm late that morning and a tropical depression that evening. Beryl accelerated northeastward until it became post-tropical the morning of July 9 while centered over Arkansas. Its remnants continued to bringing heavy rains across the central United States over the next few days.
The image above shows Beryl at peak intensity during the morning of July 2 as a category 5 hurricane. Beryl's strength was unprecedented for any hurricane ever recorded so early in Atlantic hurricane season.
Beryl had severe impacts all along its path, including the Windward Islands, Jamaica, the Yucatan peninsula, and Texas.
On June 23, a tropical wave moved over the tropical Atlantic from the western coast of Africa. The wave encountered unusually warm water and moist air for June, which allowed it to gradually develop as it moved fairly quickly westward at 15-20 mph. By June 27, a broad low pressure center had formed and a nascent circulation was evident on satellite imagery. Convection increased near the center the next day and the system was designated Tropical Depression Two. This marked the easternmost June formation of an Atlantic tropical cyclone in over 20 years.
Later that evening, the depression was upgraded to Tropical Storm Beryl. From that point, Beryl underwent rapid intensification for the next few days, exhibiting the textbook evolution of a strengthening tropical cyclone. At first an amorphous blob of thunderstorms, Beryl developed pronounced spiral bands fanning out west of the circulation center early on the 29th. By that afternoon, a central dense overcast covered the center and the system began building an eyewall. Beryl was upgraded to a hurricane that evening. To that point, conditions near the storm were quick favorable to intensification with the exception of some wind shear from the east. However, since the shear vector pointed the same direction as the storm's motion, it had less of an effect than it otherwise would. Even the shear diminished by early on June 30, however. Beryl's burst of strengthening continued and it became the first major hurricane of the 2024 Atlantic hurricane season that morning as an eye emerged on satellite. At the time it reached category 3, it was located at 10.6° N, which was farther south than any major hurricane had ever been observed in the Atlantic, with the lone exception of Hurricane Ivan in 2004, which did the same at 10.2° N.
The eye cleared out further over the next few hours and Beryl reached category 4 strength, with peak winds of 130 mph. Beryl was the first Atlantic hurricane ever recorded to reach category 4 intensity in June; the previous earliest category 4 in a season was Hurricane Dennis of 2005, which reached that intensity on July 8. By that time, the storm was approaching the Windward islands, still moving at a fairly rapid clip just north of west. The eye contracted and clouded over during the night as the core of Beryl underwent an eyewall replacement cycle. This reduced the maximum winds back to category 3 intensity but broadened the windfield. A new larger eye cleared out during the morning of July 1 and the storm resumed intensification, regaining category 4 strength. That morning, Beryl made a direct landfall in the island of Carriacou, part of the Grenadine island chain in the Windward Islands, with maximum sustained winds of 150 mph and a minimum pressure of 950 mb. The cyclone was the first known major hurricane to directly hit any of the Grenadine Islands.
Beryl continued quickly toward the west-northwest and entered the Caribbean sea that afternoon. Ocean heat content was even higher in this region, and atmospheric conditions remained favorable, so the storm deepened even further as it left the Windward Islands behind. That night, it reached category 5. Beryl eclipsed Hurricane Emily of 2005 to become the earliest category 5 on record (Emily reached this category on July 16), and was only the second recorded category 5 in July. The hurricane reached its peak intensity of 165 mph winds and a pressure of 934 mb early in the morning on July 2. After that, wind shear began to increase, disrupting Beryl. Throughout the day, the circulation became somewhat tilted toward the northeast with height and the eye lost definition until it became cloud-filled; the satellite presentation also became much less symmetric. Despite all this, the system weakened only slowly: it was reduced to category 4 during the afternoon of July 2, but maintained category 4 intensity through July 3.
Beryl's center passed just south of Jamaica during the day, but close enough that the northern eyewall crossed the coastal areas of the southwestern portion of the island. The northern eyewall had the strongest winds, so the impacts were fairly severe despite the lack of an official landfall. This land interaction and still increasing shear brought the system down to category 3 intensity overnight, but the inner core was surprisingly resilient, with at least the northern eyewall remaining intact into July 4. That morning, the storm passed south of Grand Cayman of the Cayman Islands, still a major hurricane; the center was a little further away, so the island was not affected as much as Jamaica.
The storm diminished to a category 2 that afternoon, but unexpectedly halted its weakening trend and fluctuated in strength later that day. Its continued west-northwesterly motion brought it toward the Yucatan Peninsula overnight and Beryl made landfall near Tulum as a category 2 during the morning of July 5. Fortunately, the storm started weakening again immediately prior to landfall and the windfield contracted some, limiting impacts. The cyclone's passage over the Yucatan Peninsula finally damaged it more significantly: the vortex became tilted with height and all deep convection was gone from the center by the time it emerged into the Gulf of Mexico that evening. At that time, Beryl's winds had fallen to tropical storm force. The Gulf waters, particularly immediately northwest of Yucatan, did not have as much heat content as the Caribbean Beryl had just left; further, some dry air from the southwest had been entrained into the circulation. Therefore, even once over water it took time for the system to recuperate. Strong thunderstorm activity only began to return in earnest around 12 hours after it emerged over water, during the morning of July 6.
Beryl began to feel the influence of a trough of low pressure over the central United States and it curved toward the northwest that day. The storm's battle with dry air greatly slowed intensification, though some deepening began on July 7. That night, the system approached the Texas coastline, but found more favorable conditions in its last hours over water. Beryl regained hurricane intensity and made landfall in Texas early on July 8th with peak sustained winds of 80 mph and a minimum central pressure of 979 mb. Though the cyclone was only a category 1, the curvature of the Texas coastline amplified storm surge impacts, and the storm held its own a fair way inland, bringing hurricane force winds to the Houston area.
Beryl gradually weakened as it pushed farther inland on the 8th and curved toward the northeast. The cyclone diminished to a tropical storm late that morning and a tropical depression that evening. Beryl accelerated northeastward until it became post-tropical the morning of July 9 while centered over Arkansas. Its remnants continued to bringing heavy rains across the central United States over the next few days.
The image above shows Beryl at peak intensity during the morning of July 2 as a category 5 hurricane. Beryl's strength was unprecedented for any hurricane ever recorded so early in Atlantic hurricane season.
Beryl had severe impacts all along its path, including the Windward Islands, Jamaica, the Yucatan peninsula, and Texas.
Thursday, June 20, 2024
Tropical Storm Alberto (2024)
Storm Active: June 19-20
In mid-June, a large area of disturbed weather formed from the Central American Gyre (CAG), a seasonal area of low pressure and stormy weather which extends from the southwestern Caribbean to adjacent parts of the eastern Pacific. This gyre is most pronounced near the beginning and end of hurricane season. Once the disturbance separated from the main gyre and crossed the Yucatan peninsula, it encountered favorable conditions in the Bay of Campeche and began to slowly organize. Disturbances born from the CAG are typically very large and take time to consolidate, so even though the system was already producing gale force winds by June 17, it was not yet a tropical cyclone.
It continued northwest and then west for the next couple of days, and by June 19 had a tighter circulation and a spiral band of thunderstorms extending south and west of the center. Therefore, it was named Tropical Storm Alberto, the first named storm of the 2024 Atlantic hurricane season. Fortunately, Alberto did not have time to develop an inner core and intensify quickly, but it still strengthened a little. By the morning of June 20, it had reached its peak intensity of 50 mph winds and a central pressure of 993 mb. That same morning, it made landfall in Mexico, close to the northern border of the state of Veracruz. Because Alberto had a very large windfield, there were notable storm surge impacts well to the north of the landfall point, even in the southernmost Texas coastline. Once over land, the storm quickly weakened and the circulation dissipated by that afternoon.
The image above shows Alberto as a tropical storm in the early evening of June 19.
Alberto spent just over a day as a tropical cyclone, but still caused notable rainfall and storm surge impacts.
In mid-June, a large area of disturbed weather formed from the Central American Gyre (CAG), a seasonal area of low pressure and stormy weather which extends from the southwestern Caribbean to adjacent parts of the eastern Pacific. This gyre is most pronounced near the beginning and end of hurricane season. Once the disturbance separated from the main gyre and crossed the Yucatan peninsula, it encountered favorable conditions in the Bay of Campeche and began to slowly organize. Disturbances born from the CAG are typically very large and take time to consolidate, so even though the system was already producing gale force winds by June 17, it was not yet a tropical cyclone.
It continued northwest and then west for the next couple of days, and by June 19 had a tighter circulation and a spiral band of thunderstorms extending south and west of the center. Therefore, it was named Tropical Storm Alberto, the first named storm of the 2024 Atlantic hurricane season. Fortunately, Alberto did not have time to develop an inner core and intensify quickly, but it still strengthened a little. By the morning of June 20, it had reached its peak intensity of 50 mph winds and a central pressure of 993 mb. That same morning, it made landfall in Mexico, close to the northern border of the state of Veracruz. Because Alberto had a very large windfield, there were notable storm surge impacts well to the north of the landfall point, even in the southernmost Texas coastline. Once over land, the storm quickly weakened and the circulation dissipated by that afternoon.
The image above shows Alberto as a tropical storm in the early evening of June 19.
Alberto spent just over a day as a tropical cyclone, but still caused notable rainfall and storm surge impacts.
Tuesday, May 28, 2024
Professor Quibb's Picks – 2024
My personal prediction for the 2024 North Atlantic Hurricane season (written May 28, 2024) is as follows:
24 cyclones attaining tropical depression status,
22 cyclones attaining tropical storm status,
12 cyclones attaining hurricane status, and
6 cyclones attaining major hurricane status.
This prediction far exceeds the 1991-2020 averages of 14.4 tropical storms, 7.2 hurricanes, and 3.2 major hurricanes each season. In short, I expect 2024 to be very active, with a moderate probability of breaking the top 5 most active seasons ever recorded, at least in terms of number of named storms. Below, I'll discuss the various factors that went into making this prediction.
The biggest story of the year so far in hurricane forecasting is the unprecedented warming of the tropical Atlantic ocean. For many decades, climate scientists have documented the increasing ocean temperatures caused by anthropogenic global warming, but 2024 stands out in particular.
The chart above shows the global averaged sea surface temperature since 1981. The second half of 2023 and 2024 thus far have seen average ocean temperatures far above what had been previously observed. On its own, a global ocean temperature increase should correlate to more fuel for tropical cyclone formation, but this isn't all.
The above diagram gives a snapshot from earlier this month of global sea surface temperature anomalies relative to the current mean. This means that the the large positive average anomaly from the previous image is accounted for, and we're looking at deviations from that average. One area that stands out is the tropical Atlantic, which is experiencing unusual warmth on top of an unprecedented global mean. In previous years, I've often commented on warm ocean temperatures and their contribution to more active seasons, but this year's signal is stronger than any I've seen. This factor alone is enough to predict a very active hurricane season.
One other area that stands out in the previous global ocean temperature map is the equitorial eastern Pacific, which is relatively much cooler. This signals the return of La Niña conditions, which have ramifications for global weather.
The chart above is the model forecast of the El Niño Southern Oscillation (ENSO) index, a composite measure of the sea surface temperature anomalies in the equitorial Pacific. Most of 2023 saw a positive index, called El Niño, but the index has recently been dropping, and the official conditions for a La Niña event should be met by peak hurricane season. Typically such an event is correlated with lower wind shear and hence less disruption to developing cyclones. Therefore, this is another signal in favor of an active hurricane season.
I'll run through a few more quick factors. Early indications point to a west African monsoon which is more robust than usual (this is captured, for instance, by the long-term model precipitation forecast above for the three month period August-October 2024). Many hurricanes have their origin in disturbances crossing west Africa, so this could mean that there are more "seeds" for hurricane formation; this is yet another positive factor for an active 2024. Lastly, I often consider the strength of trade winds and the magnitude of zonal wind shear across the Atlantic basin. Roughly, this is a measure of how consistent the direction and strength of the east-west component of wind is at different altitudes in the atmosphere. As mentioned above, La Niña usually leads to lower wind shear, but it's worth noting that these measures have remained close to average for 2024 thus far. This factor therefore doesn't have a significant forecast impact right now.
Next, I'll give a finer analysis of the risks by region. My estimates are on a scale from 1 (least risk) to 5 (most risk).
U.S. East Coast and Atlantic Canada: 5
The east coast of North America is at extreme risk from hurricanes this year. Ocean warmth was already discussed above, but on top of that, the likelihood of La Niña conditions and current model data both point to stronger than usual ridging over the subtropical Atlantic this summer. This means that tropical cyclone tracks have less chance of curving out to sea and an increased risk to land.
Yucatan Peninsula and Central America: 4
The same factors pointing to an active hurricane season suggest an above-normal risk for these regions. However, the predicted shear and atmospheric moisture anomalies aren't quite as favorable in the southern and western Caribbean, so I'll assign a "4" rather than a "5" here.
Carribean Islands: 5
For the last few years, many tropical cyclones forming in the tropical Atlantic had some struggles with dry air and wind shear as they approached the Caribbean; others curved out to sea before impacting the islands. This year, the risk seems much higher: a more robust African monsoon will lead to more long-track hurricanes and ample atmospheric moisture. Further, the developing La Niña will suppress shear and keep storms on a more westward track.
Gulf of Mexico: 4
As with every other region, the coast of the Gulf of Mexico is at high risk. The choice of "4" rather than "5" is due to some expected dryness, especially in the western Gulf where extreme heat and drought may prevail for significant parts of the season. The eastern Gulf should be on high alert, especially near the peak of the season in August and September.
Overall, I expect the 2024 Atlantic hurricane season to be very active, potentially historically so. Nevertheless, this is just an amateur forecast. Individuals in hurricane-prone areas should always have emergency measures in place. For more on hurricane safety sources, see here. Remember, devastating storms can occur even in otherwise quiet seasons.
Sources: https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf, https://tropical.colostate.edu/Forecast/2024-04.pdf, https://www.tropicaltidbits.com/analysis/models/, https://www.noaa.gov/news-release/noaa-predicts-above-normal-2024-atlantic-hurricane-season
24 cyclones attaining tropical depression status,
22 cyclones attaining tropical storm status,
12 cyclones attaining hurricane status, and
6 cyclones attaining major hurricane status.
This prediction far exceeds the 1991-2020 averages of 14.4 tropical storms, 7.2 hurricanes, and 3.2 major hurricanes each season. In short, I expect 2024 to be very active, with a moderate probability of breaking the top 5 most active seasons ever recorded, at least in terms of number of named storms. Below, I'll discuss the various factors that went into making this prediction.
The biggest story of the year so far in hurricane forecasting is the unprecedented warming of the tropical Atlantic ocean. For many decades, climate scientists have documented the increasing ocean temperatures caused by anthropogenic global warming, but 2024 stands out in particular.
The chart above shows the global averaged sea surface temperature since 1981. The second half of 2023 and 2024 thus far have seen average ocean temperatures far above what had been previously observed. On its own, a global ocean temperature increase should correlate to more fuel for tropical cyclone formation, but this isn't all.
The above diagram gives a snapshot from earlier this month of global sea surface temperature anomalies relative to the current mean. This means that the the large positive average anomaly from the previous image is accounted for, and we're looking at deviations from that average. One area that stands out is the tropical Atlantic, which is experiencing unusual warmth on top of an unprecedented global mean. In previous years, I've often commented on warm ocean temperatures and their contribution to more active seasons, but this year's signal is stronger than any I've seen. This factor alone is enough to predict a very active hurricane season.
One other area that stands out in the previous global ocean temperature map is the equitorial eastern Pacific, which is relatively much cooler. This signals the return of La Niña conditions, which have ramifications for global weather.
The chart above is the model forecast of the El Niño Southern Oscillation (ENSO) index, a composite measure of the sea surface temperature anomalies in the equitorial Pacific. Most of 2023 saw a positive index, called El Niño, but the index has recently been dropping, and the official conditions for a La Niña event should be met by peak hurricane season. Typically such an event is correlated with lower wind shear and hence less disruption to developing cyclones. Therefore, this is another signal in favor of an active hurricane season.
I'll run through a few more quick factors. Early indications point to a west African monsoon which is more robust than usual (this is captured, for instance, by the long-term model precipitation forecast above for the three month period August-October 2024). Many hurricanes have their origin in disturbances crossing west Africa, so this could mean that there are more "seeds" for hurricane formation; this is yet another positive factor for an active 2024. Lastly, I often consider the strength of trade winds and the magnitude of zonal wind shear across the Atlantic basin. Roughly, this is a measure of how consistent the direction and strength of the east-west component of wind is at different altitudes in the atmosphere. As mentioned above, La Niña usually leads to lower wind shear, but it's worth noting that these measures have remained close to average for 2024 thus far. This factor therefore doesn't have a significant forecast impact right now.
Next, I'll give a finer analysis of the risks by region. My estimates are on a scale from 1 (least risk) to 5 (most risk).
U.S. East Coast and Atlantic Canada: 5
The east coast of North America is at extreme risk from hurricanes this year. Ocean warmth was already discussed above, but on top of that, the likelihood of La Niña conditions and current model data both point to stronger than usual ridging over the subtropical Atlantic this summer. This means that tropical cyclone tracks have less chance of curving out to sea and an increased risk to land.
Yucatan Peninsula and Central America: 4
The same factors pointing to an active hurricane season suggest an above-normal risk for these regions. However, the predicted shear and atmospheric moisture anomalies aren't quite as favorable in the southern and western Caribbean, so I'll assign a "4" rather than a "5" here.
Carribean Islands: 5
For the last few years, many tropical cyclones forming in the tropical Atlantic had some struggles with dry air and wind shear as they approached the Caribbean; others curved out to sea before impacting the islands. This year, the risk seems much higher: a more robust African monsoon will lead to more long-track hurricanes and ample atmospheric moisture. Further, the developing La Niña will suppress shear and keep storms on a more westward track.
Gulf of Mexico: 4
As with every other region, the coast of the Gulf of Mexico is at high risk. The choice of "4" rather than "5" is due to some expected dryness, especially in the western Gulf where extreme heat and drought may prevail for significant parts of the season. The eastern Gulf should be on high alert, especially near the peak of the season in August and September.
Overall, I expect the 2024 Atlantic hurricane season to be very active, potentially historically so. Nevertheless, this is just an amateur forecast. Individuals in hurricane-prone areas should always have emergency measures in place. For more on hurricane safety sources, see here. Remember, devastating storms can occur even in otherwise quiet seasons.
Sources: https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf, https://tropical.colostate.edu/Forecast/2024-04.pdf, https://www.tropicaltidbits.com/analysis/models/, https://www.noaa.gov/news-release/noaa-predicts-above-normal-2024-atlantic-hurricane-season
Monday, May 6, 2024
Hurricane Names List – 2024
The name list for tropical cyclones forming in the North Atlantic basin for the year 2024 is as follows:
Alberto
Beryl
Chris
Debby
Ernesto
Francine
Gordon
Helene
Isaac
Joyce
Kirk
Leslie
Milton
Nadine
Oscar
Patty
Rafael
Sara
Tony
Valerie
William
This list is the same as that for the 2018 season, with the exception of Francine and Milton, which replaced the retired names Florence and Michael, respectively.
Alberto
Beryl
Chris
Debby
Ernesto
Francine
Gordon
Helene
Isaac
Joyce
Kirk
Leslie
Milton
Nadine
Oscar
Patty
Rafael
Sara
Tony
Valerie
William
This list is the same as that for the 2018 season, with the exception of Francine and Milton, which replaced the retired names Florence and Michael, respectively.
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