Tropical Storm Harvey finally moved into Louisiana on Wednesday after lingering for several days over the northwestern Gulf of Mexico. Harvey weakened to a tropical depression after it moved inland. At the same time a new tropical storm named Irma strengthened quickly over the eastern Atlantic Ocean. At 11:00 p.m. EDT on Wednesday the center of Tropical Depression Harvey was located at latitude 31.7°N and longitude 92.3°W which put it about 30 miles (50 km) north-northeast of Alexandria, Louisiana. Harvey was moving toward the north-northeast 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 998 mb.
After dropping record rainfall and causing destructive floods of parts of southeastern Texas and western Louisiana, Tropical Depression Harvey finally started to move steadily toward the north-northeast on Wednesday. Harvey was still producing heavy rain over parts of western Louisiana, but the fact that it was moving should limit the total rainfall at any location. Bands of showers and thunderstorms on the far eastern periphery of Harvey’s circulation were also dropping heavy rain. Some of those thunderstorms were strong enough to approach severe criteria. Tropical Depression Harvey is forecast to move toward the Ohio River Valley during the next several days and it will bring windy, wet weather to the Middle Mississippi and Ohio River Valleys. Rain associated with the circulation of Tropical Depression Harvey could also reach the Mid-Atlantic States later this week.
At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Irma was located at latitude 16.4°N and longitude 32.2°W which put it about 545 miles (875 km) west of the Cabo Verde Islands. Irma was moving toward the west at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 999 mb.
The circulation of Tropical Storm Irma organized quickly on Wednesday. Numerous bands of showers and thunderstorms formed and began to revolve around a well organized center of circulation. Thunderstorms in the core of Irma generated well developed upper level divergence which pumped away mass in all direction. There were occasional satellite images which hinted that an eye could be forming at the center of Tropical Storm Irma.
Tropical Storm Irma will be moving through an environment that will be favorable for intensification. Irma will move over water where the Sea Surface Temperature is near 28°C. The upper level winds are weak and there is little vertical wind shear. Irma is likely to become a hurricane on Thursday and it could intensify rapidly if an eye forms. Tropical Storm Irma is forecast to become a major hurricane and it could become one of the big classic Cape Verde hurricanes.
A strong subtropical high to the north of Irma is steering the tropical storm toward the west and a general westerly motion is forecast to continue for the next few days. There is more divergence in the model guidance after a few days and the future track of Irma when it nears the Lesser Antilles is more uncertain. Tropical Storm Irma has the potential to become a big dangerous hurricane and it will need to be watched carefully.