NOAA's high-resolution HWRF computer forecast map for late Saturday night; courtesy tropicaltidbits.com, NOAA
Amazingly, the state of Florida has not had a hurricane of any intensity since Wilma came ashore in southwestern Florida during late October of 2005. Hurricane Wilma was also the last major hurricane (i.e., category 3, 4 or 5) to strike US soil in what has turned out to be another amazing streak. As the climatological peak of the Atlantic Basin hurricane season approaches (mid-September), we now have quite an active scene with three different tropical systems. Tropical Depression Fiona is in a weakening state and should have little or no impact on the US. Tropical Storm Gaston is situated in the far eastern Atlantic Ocean and it will likely strengthen significantly over the next several days as it heads in a general northwest fashion, but it may never make it to the US coastline. And then there is the third system - which is yet to be named - currently sitting a few hundred miles east of the Leeward Islands. It is this system that has a good chance of intensification over the next few days (would become named Hermine), and it could very well end the hurricane drought in Florida by the early part of next week.
IR satellite image of the Atlantic Ocean; courtesy University of Wisconsin/CIMSS
A large area of showers and thunderstorms is sitting a few hundred miles east of the Leeward Islands and environmental conditions are favorable for intensification over the next few days as it churns west-to-northwest. First of all, this system has “escaped” the large area of Saharan (dry) Desert air that currently resides in the area much closer to the west coast of Africa (image below). In other words, this tropical wave is entering an area of higher water vapor content which is favorable for future development. Second, sea surface temperature anomalies are positive (i.e., warmer-than-normal) throughout the Caribbean Sea, Gulf of Mexico and Bahama Island regions. This is also a favorable factor for intensification of this particular tropical system. "Hurricane hunters" will visit the disturbance later today shedding more light on its prospects for development.
Compilation of predicted storm tracks from numerous computer models with general agreement that Florida could be visited by "Hermine"; courtesy UCAR, NCAR, NOAA/NCEP
Current computer model forecasts strongly suggest a track for this system of skirting the northern Caribbean Islands and then closing in on southern Florida by the latter part of the weekend. There is a chance that this system – to become named Hermine – could make landfall in Florida as a hurricane by the end of the weekend or early part of next week and this would end the unprecedented streak for the state without a hurricane. The Hurricane Weather Research and Forecasting (HWRF) model is a specialized version of the Weather Research and Forecasting (WRF) model and is used by NOAA to forecast the track and intensity of tropical cyclones. The HWRF forecast map (top) for late Saturday night is rather ominous looking for the Bahamas and the state of Florida.
Dry (Saharan Desert) air (orange) off west coast of Africa; map courtesy University of Wisconsin/CIMSS
Sea surface temperature anomalies with warmer-than-normal conditions dominating the entire region (yellow, orange); courtesy NOAA
Meteorologist Paul Dorian