Storm Active: November 4-
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.
As of 4:00pm EST on November 4, 2024, Tropical Storm Rafael had maximum sustained winds of 45 mph, a central pressure of 997 mb, and was moving north at 9 mph. For more up-to-date information and the latest watches and warnings, please consult the National Hurricane Center.
Monday, November 4, 2024
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.
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