Invest 91L has been upgraded to Tropical Storm Tomas as of the 5PM advisory from the NHC. Earlier today, the reconnaissance plane had found that a closed surface circulation was forming and on the way to becoming a tropical storm. TS Tomas is expected to continue slow strengthening and may become a hurricane by Sunday. There is the possibility that TS Tomas may become a major hurricane later in the forecast period.
The models now are forecasting that TS Tomas will continue to head WNW for at least the next 72 hours. The broad trough over the US is now expected to pull out, and this will leave a ridge to build over Tomas and all the way to Florida. Later on, a second and much deeper trough will begin to dig southward into the Southeastern U.S. and this will cause the ridge and all the steering flow to weaken. This will cause Tomas to sharply decrease the forward speed in about 120 hours. It is too early to call whether Tomas will bypass the trough and continue heading WNW or whether the trough will begin to force TS Tomas to head NW then North or not.
NO MATTER where TS Tomas heads, all interests should keep advised of the location that Tomas is heading, especially if he becomes a major hurricane.
