Monthly Archives: September 2021

Larry Strengthens to a Hurricane

Former Tropical Storm Larry strengthened to a hurricane over the eastern Atlantic Ocean early on Thursday. At 5:00 a.m. EDT on Thursday the center of Hurricane Larry was located at latitude 13.0°N and longitude 32.3°W which put it about 545 miles (875 km) west-southwest of the Cabo Verde Islands. Larry was moving toward the west at 20 m.p.h. (32 km/h). The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h). The minimum surface pressure was 987 mb.

Former Tropical Storm Larry intensified quickly during the past 24 hours and it reached hurricane intensity early on Thursday morning. The inner end of a rainband wrapped around the center of Hurricane Larry and an eye appeared intermittently on visible and microwave satellite images. Bands of showers and thunderstorms were revolving around the center of Larry. Storms near the center generated upper level divergence that pumped mass away to the west of the hurricane. Winds to hurricane force extended out 20 miles (30 km) from the center of Larry. Winds to tropical storm force extended out 80 miles (130 km) from the center of circulation.

Hurricane Larry will move through an environment favorable for intensification during the next several days. Larry will move over water where the Sea Surface Temperature is near 27.5˚C. It will move under the southern side of an upper level ridge over the eastern Atlantic Ocean. The ridge will produce easterly winds that will blow toward the top of Larry’s circulation. Those winds will cause some vertical wind shear. The winds in the lower levels will also blow from the east and so there will not be a lot of vertical wind shear. Hurricane Larry will strengthen during the next 48 hours and it could intensify to a major hurricane. Hurricane could undergo a period of rapid intensification once an inner core with an eye and an eyewall are fully formed.

Hurricane Larry will move around the southern side of a subtropical high pressure system over the Atlantic Ocean. The high will steer Larry toward the west during the next several days. On its anticipated track Hurricane Larry will move farther away from the Cabo Verde islands. Larry could be east of the northern Leeward Islands by the weekend.

Elsewhere, the remnants of former Hurricane Ida interacted with a slow moving cold front to cause widespread urban and flash floods in the northeastern U.S. At 5:00 a.m. EDT on Thursday the center of the remnants of former Hurricane Ida was located at latitude 41.4°N and longitude 71.6°W which put it about 40 miles (65 km) southwest of Providence, Rhode Island. Ida was moving toward the northeast at 28 m.p.h. (43 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 998 mb. There were reports of urban and flash floods in central and eastern Pennsylvania, northern New Jersey and southeastern New York including New York City. There were reports of tornadoes in Maryland and New Jersey.

Tropical Storm Larry Forms South of Cabo Verde Islands

Tropical Storm Larry formed south of the Cabo Verde Islands on Wednesday morning. At 5:00 a.m. EDT on Wednesday the center of Tropical Storm Larry was located at latitude 12.3°N and longitude 24.8°W which put it about 175 miles (280 km) south of the Cabo Verde Islands. Larry was moving toward the west at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 1003 mb.

Satellite images indicated that former Tropical Depression Twelve had strengthened on Wednesday morning and the National Hurricane Center designated the system as Tropical Storm Larry. The circulation around Tropical Storm Larry exhibited more organization. More thunderstorms formed near the center of Larry. Even though the circulation was more organized, the distribution of thunderstorms was asymmetrical. Many of the thunderstorms were occurring in bands south and west of the center of Tropical Storm Larry. Bands in the northern and eastern parts of Larry consisted primarily of showers and lower clouds. Storms near the center of circulation began to generate upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 70 miles (110 km) on the western side of Larry. The winds on the eastern side of the circulation were blowing at less than tropical storm force.

Tropical Storm Larry will move through an environment favorable for intensification during the next few days. Larry will move over water where the Sea Surface Temperature is near 27.5˚C. It will move under the southern side of an upper level ridge over the eastern Atlantic Ocean. The ridge will produce easterly winds that will blow toward the top of Larry’s circulation. Those winds will cause some vertical wind shear. The winds in the lower levels will also blow from the east and so there will not be a lot of vertical wind shear. Tropical Storm Larry will strengthen during the next few days. Larry could intensify to a hurricane within 36 hours. Tropical Storm Larry could undergo a period of rapid intensification once an inner core with an eye and an eyewall form. Larry could intensify to a major hurricane during the weekend.

Tropical Storm Larry will move around the southern side of a subtropical high pressure system over the Atlantic Ocean. The high will steer Larry toward the west during the next several days. On its anticipated track Tropical Storm Larry will move farther away from the Cabo Verde islands. Larry could be east of the northern Leeward Islands by the weekend.

Elsewhere, Tropical Depression Ida was dropping locally heavy rain over parts of the U.S. and Tropical Depression Kate was spinning northeast of the Leeward Islands. At 5:00 a.m. EDT on Wednesday the center of Tropical Depression Ida was located at latitude 37.3°N and longitude 82.5°W which put it about 75 miles (120 km) west of Bluefield, West Virginia. Ida was moving toward the northeast at 24 m.p.h. (39 km/h). The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h). The minimum surface pressure was 1000 mb. Flash Flood Watches were in effect for the region from West Virginia and eastern Ohio to southern New England.

At 5:00 a.m. EDT on Wednesday the center of Tropical Depression Kate was located at latitude 25.7°N and longitude 51.7°W which put it about 895 miles (1440 km) northeast of the northern Leeward Islands. Kate was moving toward the north-northwest at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1007 mb.