Tropical Storm Omar (2020)

Storm Active: August 31-September 5

Around August 29, an upper-level low pressure area began to produce thunderstorm activity over the northeastern Gulf of Mexico. It moved over land shortly afterward, which temporarily stifled development. On the 30th, the system emerged over the Atlantic just east of Georgia and developed a surface circulation. It was moving around the northwestern edge of a ridge, and followed the boundary northeast. By the afternoon of August 31, enough convection had appeared near the center for the low to be upgraded to Tropical Depression Fifteen.

The depression was located over warm water, but it was quickly moving into an area with higher shear out of the west. As a result, the center swirl remained exposed on satellite imagery. Winds increased a little in the thunderstorms east of the center on September 1, which bumped up the system to tropical storm strength. It was named Tropical Storm Omar (the name Nana was given to a western Caribbean storm earlier that same afternoon). The earliest "O" storm record fell; it was previously held jointly by 2005's Ophelia, which was named on September 7, and 2011's Nate, which was named also on that date. The 15th "named" storm was the "N" storm and not the "O" in 2011 because of the unnamed tropical storm that formed August 31 of that year.

Omar put up a decent fight against unfavorable upper-level winds, which became more northerly overnight and into September 2. It maintained tropical depression status through that afternoon as it passed well north of Bermuda. However, shear was really piling on. It exceeded 40 knots by early that evening and Omar weakened to a depression. The struggling cyclone still produced enough convection intermittently to maintain its status through September 3. Omar also interacted with a nontropical low to its northeast that day and took a dip toward the east-southeast. Remarkably, it was still hanging on a day later.

A front began to approach the system from the northwest and it turned toward the north on September 5. This brought it over cooler water, finally bringing Omar's journey to a close late that afternoon when it was downgraded to a remnant low.

Omar was a weak tropical cyclone beset by strong shear, but it managed to hang on a few days longer than expected.

Omar did not affect any land areas.

Hurricane Marco (2020)

Storm Active: August 20-25

Around August 10, another tropical wave moved off the coast of Africa. Initially, atmospheric conditions did not favor development and the system did not produce much thunderstorm activity as it traversed the tropical Atlantic. It was only upon approach to the Lesser Antilles around August 16 that it showed signs of organization. The wave produced some rain for the islands as it passed into the Caribbean the next day, but its fast forward speed kept these rains short-lived. A broad low pressure center formed in association with the wave on the 18th. As the system neared the southwestern edge of the subtropical ridge, its forward motion slowed and allowed some more consolidation. Very deep convection blossomed late on August 19 and Tropical Depression Fourteen formed the next morning.

The depression had a curious structure that day, featuring a warm spot on satellite imagery near what appeared to be a mid-level circulation even though surface and aircraft reconnaissance data indicated a surface low further south. The storm did not intensify over the next day, thanks in part to land interaction with Honduras, which Fourteen passed very close to overnight. Feeling the influence of a trough over the Gulf of Mexico, the depression turned rather sharply toward the north and slowed down during the morning of August 21. Outflow from the same trough lay some sinking air over Fourteen, limiting convective activity.

Interestingly, the storm began to build a central dense overcast that evening "from scratch," building an expanding core over the next day. Late in the evening (early on the 22nd UTC time), it strengthened into Tropical Storm Marco. This once again marked a new record for earliest "M" storm, this time surpassing a tie between Maria of 2005 and Lee of 2011, which both formed on September 2. Note that in the second case, though Lee wasn't technically an "M" storm, it was still the thirteenth tropical storm-strength cyclone of the season, in light of the unnamed tropical storm that was identified in post-season analysis. Marco sat atop the highest ocean heat content in the Atlantic, and tapped into it on the 22nd, strengthening rapidly into a strong tropical storm.

Defying forecasts, Marco traveled north-northwest most of the day. Instead of hitting the Yucatan Peninsula, it passed east, in between Cuba and Mexico. In fact, of the two landmasses, only the western tip of Cuba received tropical storm conditions as the storm passed. The storm entered the Gulf of Mexico, where very warm ocean waters and high relative humidity prevailed. As Marco moved north-northwest closer to the trough mentioned earlier though, wind shear steadily increased out of the southwest. As a result, the satellite presentation looked a little "squashed" in the southwest quadrant. The storm fought it off on August 23 enough to strengthen to a category 1 hurricane, reaching its peak intensity with 75 mph winds and a pressure of 991 mb.

But the shear was relentless and increased to over 30 knots that evening, causing the storm to begin to decouple. This began a period of rapid weakening and Marco lost its brief hurricane status. All convection was displaced from the center overnight, so that even though the center was headed toward the Louisiana coastline, that state received almost no rain! The heavy rain that did occur was from the displaced thunderstorms over the Florida panhandle and coastal Alabama. By the afternoon of the 24th, Marco was a weak tropical storm. The center of circulation turned abruptly westward and made landfall near the mouth of the Mississippi river that evening. The weakening vortex paralleled the Louisiana coastline overnight as Marco weakened to a tropical depression, and then a remnant low early on August 25. This low dissipated within a day as Hurricane Laura approached from the southwest.

The above image shows Marco near peak intensity. Notice the straight line cloud formations to the north and the strong winds pushing them toward the northeast. These upper-level winds are what caused Marco to rapidly weaken before landfall.

Despite forming in the Caribbean, Marco took a path that resulted in relatively few land impacts.

Hurricane Laura (2020)

Storm Active: August 19-29

During mid-August, a huge tropical wave traversed the African Sahel, producing massive amounts of rain in west Africa. This impressive feature emerged over the Atlantic on August 15 and moved quickly westward. The system organized only slowly, hampered primarily by its own large size and competing regions of vorticity on the eastern and western edge of the disturbance. Ultimately, convective activity dissipated in the eastern blob and the western end won out. On August 19, the circulation became defined enough to designate the system Tropical Depression Thirteen.

By that time, the depression was moving rapidly west-northwestward and contending with a bit of dry air to the west. This kept development slow in an otherwise favorable environment with warm air and low shear. During the afternoon of August 20, it became evident that multiple low-level swirls existed in the system as one was ejected northwestward out around of the convective canopy. That swirl ultimately dissipated and the center was hard to locate overnight. Nevertheless, thunderstorm coverage increased some the next day as the depression approached the Leeward Islands. Aircraft reconnaissance found tropical storm force winds during the morning of the 21st, prompting an upgrade to Tropical Storm Laura. Laura was the new earliest "L" storm and surpassed the record of Hurricane Luis, which formed on August 28, 1995 (00:00 August 29 in UTC time).

Despite the upgrade, Laura was disheveled on satellite imagery as its bands brought rain to the northeasternmost Caribbean islands. Some improvement to its structure took place overnight and thunderstorm activity became much more widespread. On August 22, instead of no apparent center, there were two: a low-level one moving on a more southerly track south of Puerto Rico, and a mid-level one which crossed the island and ultimately emerged north of it that afternoon. This separation prevented Laura from strengthening quickly, but its winds nevertheless increased to 50 mph that day. On the other hand, the large-scale circulation of Laura was very vigorous and barely slowed down as it went directly across Hispaniola beginning that evening.

Torrential rainfall occurred in both Haiti and the Dominican Republic over the next day, leading to widespread flooding even though Laura was still moving around 20 mph toward the west-northwest. The cyclone deepened a bit more during the afternoon of August 23 as it emerged over water briefly and began to move close to eastern Cuba. A bit of wind shear out of the north pushed some drier land air into the northern semicircle as Laura passed over the waters between Cuba and Jamaica overnight. During the day of the 24th, the structure began to improve again. The storm moved back over land in western Cuba that evening, but it wasn't long until it emerged into the Gulf of Mexico. Even as it exited land, an inner core began to develop.

Steady strengthening commenced once Laura was over water; it became a hurricane the morning of the 25th. It was still moving west-northwest fairly quickly (though slower than before) and so the main difficulty was moistening the slightly drier air mass it was moving into. Thus the storm had the most difficulty closing an eyewall on the western side. Cold cloud tops eventually wrapped all the way around the center that afternoon. That evening, Laura began an extreme bout of rapid intensification. The storm's outflow became more pronounced and its banding more symmetric overnight as it strengthened to a category 2 hurricane. An eye appeared early on August 26 and Laura became the first major hurricane of the season. It also made a turn toward the northwest as it felt the influence of a trough to the north.

The eye cleared out and became more circular in the afternoon as the ring of cold cloud tops around it widened. Soon, the storm reached category 4 status and completed an increase in winds of 65 mph over a period of 24 hours. At the same time, outer bands swept across the Gulf coast of Louisiana and neighboring states, bringing strong winds and isolated tornadoes. Laura's intensity finally leveled out that evening just before landfall, with winds of 150 mph and a minimum central pressure near 938 mb. Just after midnight local time, the eye came ashore in southwestern Lousiana, bringing tremendous storm surge and wind. Its landfalling windspeed of 150 mph was the highest recorded for a Louisiana hurricane since 1856! Even Katrina had lower winds, though its pressure was lower and storm surge higher. In addition, the inundated area was primarily marshland and much less populated than the area Katrina had impacted 15 years prior.

Laura quickly weakened over land and lost hurricane status during the morning of August 27. Later that day, it moved northward into Arkansas. By this time, the radar presentation had degraded significantly. The system weakened to a tropical depression that evening and began a turn toward the east. It brought rain to Ohio Valley and ultimately the southern part of the mid-Atlantic, but impacts were minor. Laura became post-tropical early on August 29 and soon sped eastward into the open Atlantic.

The above image shows Laura at category 4 intensity on August 26.

Laura passed over nearly all of the Greater Antilles as a tropical storm without significant weakening. Once it was over warm waters, it became one of the fastest intensifying Gulf of Mexico hurricanes on record.

Tropical Storm Kyle (2020)

Storm Active: August 14-16

On August 13, thunderstorm activity associated with a broad area of low pressure near the North Carolina coastline showed some evidence of spin on radar imagery, though heavy rain remained offshore. Surprisingly, the disturbance quickly gained organization: the center of circulation moved offshore overnight and convection developed near the center of circulation. Some easterly shear kept the developing vortex a little tilted, but the system was strong enough to be designated Tropical Storm Kyle that afternoon. At that time, it was accelerating east-northeastward away from the coastline. Kyle continued piling on the named storm records for 2020; it was the earliest "K" storm, replacing Katrina of 2005, which formed on August 24 of that year.

The system was not very organized, as the center remained west of any thunderstorm activity. Further, upper-level winds caused the circulation to elongate east to west. Despite these difficulties, the warm Gulf Stream waters fueled some stronger sustained winds overnight, bringing them to 50 mph. Wind shear continued to increase and Kyle began extratropical transition that afternoon. The vorticity was so stretched out that additional deep convection overnight could not stall this transformation. The storm lost tropical status early on August 16. Within a few days, the remnants of Kyle merged with another extratropical low. The combined system strengthened explosively over the northeast Atlantic on August 18 and ultimately brought gale force winds to western Europe.

The above images shows Kyle just after classification as a tropical storm on August 14.

Despite forming close to land, Kyle moved quickly out to sea and did not have any impacts on land as a tropical cyclone.

Tropical Storm Josephine (2020)

Storm Active: August 11-16

On August 8, another member of the train of tropical waves exited Africa. It moved more slowly to the west than its July predecessors that became named storms; this is typical as trade winds lessen toward the end of summer. The next day, a broad low-pressure center formed. The disturbance surrounding the low was rather large and the center itself was initially elongated. Gradually, it overcame these obstacles and developed a concentrated blob of thunderstorm activity. By late on August 10, its only issue was wind shear out of the east, resulting in convection displaced north and west. Some new blow ups near the center on August 11 remedied this enough for the system to be classified Tropical Depression Eleven that afternoon.

Nighttime brought with it more thunderstorm activity, but there was little evidence of banding features until the morning of the 12th, when a spiral band developing looping outward north and east from the center. At the same time, wind shear lessened, but the storm had trouble maintaining persistent convection. Overnight, it turned west-northwest, and on August 13 was upgraded to Tropical Storm Josephine, the new earliest "J" storm. It claimed that record from Jose of 2005, which was named on August 22. Despite the upgrade, the storm spent most of the next couple days as a formless blob of convection. Also, the center likely reformed to the north during the day of August 14, sending the storm on a more northwest trajectory in the short-term.

Josephine made its closest approach to the Lesser Antilles on August 15, but it stayed far enough north that there were minimal impacts, especially since the storm had little rain in its southwest quadrant. Wind shear increased even more that day and set the storm on a weakening trend. During the morning of August 16, it was downgraded to a tropical depression, and shortly after it degenerated into a trough of low pressure. The remnants of Josephine brought some rain to Bermuda a little while after.

Josephine was a relatively small cyclone, shown above on August 13.

The tropical storm traveled over warm ocean waters its whole lifetime, but strong wind shear prevented significant strengthening and ultimately caused Josephine's demise.