The National Hurricane Center finally declared the low pressure system approaching the Caribbean as Tropical Storm Bertha. The newly-minted tropical system is the second of the year, and has sustained winds of 45 MPH as it heads towards the Lesser Antilles. It may pose a slight threat to the East Coast next week.
The system developed enough thunderstorm activity near its center this evening to reach the minimum criteria needed to be declared a tropical storm. Earlier this afternoon, NOAA Hurricane Hunters found that the system had 40-45 MPH winds at the surface, but without thunderstorms around its center, it was nothing but partly cloudy and windy.
Tropical Storm Warnings are in effect for Barbados and Dominica, as well as St. Lucia. Tropical Storm Watches are in effect for Puerto Rico and the U.S. Virgin Islands, along with St. Vincent and The Grenadines. Bertha faces a somewhat uncertain future as it traverses the Antilles over the next couple of days.
After the storm moves over the Greater Antilles and clears the Caribbean, it may strengthen somewhat as it makes a glancing approach with the southeastern coast of the United States. Great uncertainty exists five days out in any forecast, and especially so with tropical cyclone forecasts. The storm could hit the U.S. or recurve out to sea and nobody will even see clouds from it. It's too soon to tell, but given the models and the NHC's forecast track, it's worth watching if you live along the East Coast.
The NHC issues advisories every six hours when a storm is out at sea, and every three hours when one threatens land. The agency's next advisory will be released at 200AM EDT.
[maps by the author]