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Posted at 03:05 PM ET, 08/19/2011

Tropical storm Harvey forms; watchful eyes on trailing disturbance

Track forecast for tropical storm Harvey. Tropical storm warnings in blue, tropical storm watches in orange. (National Hurricane Center)
Tropical depression eight has officially reached tropical storm status, earning the name Harvey this afternoon. Located 285 miles east southeast of Belize City in the western Caribbean, the storm has prompted tropical storm warnings for the Bay Islands of Honduras and the coast of Belize.

Maximum sustained winds are 40 mph and the National Hurricane Center forecasts some strengthening prior to landfall along the coast of Belize Saturday or Saturday night. Three to five inches of rain are forecast across Honduras, Guatemala and Belize, with isolated totals to 8”.

While Harvey may produce dangerous flash flooding and mudslides in Central America, interests in the United States are more focused on the trailing disturbance in the central Atlantic, known as 97L.

Infrared satellite image of disturbance 97L. (NOAA)
For several days, computer models have been consistently strengthening 97L and tracking it towards the U.S. East Coast. Officially, the National Hurricane Center gives it a 40% chance of developing into a tropical depression or storm in the next 48 hours.

However, it’s beyond 48 hours when the prospects for the intensification of 97L increase. It’s currently in survival mode, battling dry, stable air on its westbound journey towards the Lesser Antilles. If it holds together, 97L should encounter a more favorable environment in the eastern Caribbean.

Forecast track of 97L ( South Florida Water Management District )
On the other hand, the forecast track of 97L carries it over Puerto Rico, Hispaniola (Dominican Republic and Haiti), and possibly Cuba. The interaction with land could well be devastating to its development chances.

Latest Euro model takes 97L or possibly “Irene” over south Florida. This is just one low skill simulation and is very likely to change in the coming days. (
So 97L may or may not overcome these obstacles. If it does, then its ultimate track is still in question. Whereas models had steered the disturbance towards the southeast U.S. coast the last couple of days, newer guidance is more to the south and west which could take it into the eastern Gulf of Mexico.

Models have simulated the system being captured by the trough (dip in the jet stream) forecast to be over the eastern third of the U.S. late next week, turning it north. Depending on exactly how it’s configured (and how strong it is), winds/rain could impact portions of the East. Again, this is predicated on the disturbance remaining intact.

In sum, there are more questions than answers right now about the fate of this system. Capital Weather Gang tropical weather expert Greg Postel put it this way:

“It has a long way to go both figuratively and literally. At the same time, there’s a growing consensus in the models that a tropical system will be in the Caribbean late in the weekend with an improving environment for intensification.”

Everyone along Gulf and East Coasts should keep tabs on it.

By  |  03:05 PM ET, 08/19/2011

Categories:  Tropical Weather, Latest

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