A tropical storm warning is already in place for the northwestern Bahamas
The chances that a tropical cyclone will blow through South Florida this weekend are escalating as an area of widespread storminess over the southeastern Bahamas gets better organized.
National Hurricane Center forecasters began issuing advisories Thursday on Potential Tropical Cyclone Nine — a designation that allows watches and warnings to go into effect before a disturbance is fully developed.
Tropical storm warnings were issued by the government of the Bahamas for its northwesthern islands including Grand Bahama and the Abacos, which were just devastated by Category 5 Hurricane Dorian.
Palm Beach County and the Treasure Coast could see watches or warnings issued overnight Thursday or Friday as the forecast track of the system brings it to Florida’s east coast on Saturday.
If a storm forms, it would be named Humberto.
The official forecast has the system topping out as a tropical storm with sustained 50-mph winds and a path that includes areas from Hollywood through Jacksonville and west to Tallahassee.
Robert Molleda, warning coordination meteorologist with the National Weather Service in Miami, said South Florida’s weekend weather depends on where the system goes, which was still a question mark late Thursday.
If it moves north of the Bahamas off Florida’s central coast, it could mean lower chances of rain over the weekend.
A path that develops the system farther south would mean gusty to tropical-storm-force winds and rainfall amounts as high as 5 inches in coastal Palm Beach County.
“The worse-case scenario would be a tropical storm affecting South Florida and moving right over it, and that’s certainly a possibility,” Molleda said. “Right now we should prepare for the potential for a windy, rainy event with showers increasing Friday.”
The squally weather is expected to be the strongest Friday night through Saturday with rain chances as high as 70 percent both days.
Unlike Hurricane Dorian’s damaging stall over the Bahamas, the would-be Humberto was moving northwest at 8 mph and should continue to be steered by a high pressure system to its north.
An Air Force hurricane hunter was scheduled to investigate the system Thursday afternoon.
The National Weather Service in Miami is warning of possible tornadoes as the system passes near South Florida. A high risk of dangerous rip currents is in place at least through Friday. Heavy rain with localized flooding are also possible.
Sea surface temperatures in the Bahamas are near 84 degrees, plenty warm to feed a burgeoning system.
Weather Underground co-founder Jeff Masters said there the system’s path is “highly uncertain.”
Leading weather models have two different tracks, one taking it across South Florida into the Gulf of Mexico and another running it up the east coast on a path similar to Dorian’s.
“It will be highly dependent upon where and when the center ultimately forms, and that location could be anywhere within a 100-mile radius of the south-central Bahamas,” Masters wrote in a forecast Thursday. “The main thing we are sure about at this point is that 95L will bring regions of heavy rains of 2 to 4 inches over the next two days to the Bahamas, including the islands devastated by Hurricane Dorian.”
Hurricane center forecasters also emphasized the low confidence they have in where the system will go.
“Both the track and intensity forecasts are highly uncertain, more than usual I would say,” said NHC hurricane specialist Lixion Avila.
Another system in Atlantic has 40 percent chance of formation over 5 days
The NHC also is watching a second system in the tropical Atlantic that was picking up steam Thursday.
The wave, located just west of the Cabo Verde Islands, is producing a small area of disorganized showers and thunderstorms. With conditions improving ahead of it for development, the NHC is giving the system a 40 percent chance of formation over five days.
South Florida temperatures are expected to be near normal through the weekend with highs near 90. But it will be abnormally warm at night, dipping to just 80 degrees. The normal overnight low this time of year is 75.
West Palm Beach dipped only to 83 degrees Wednesday morning, breaking an overnight heat record of 82 set in 2008.
With some disagreement in where the would-be Humberto will track, Miami forecasters weren’t ruling out the possibility of some drier air this weekend.
“If a more easterly/northerly track comes to fruition, the likely lopsided nature of weather tropical systems would potentially bring some drier air around the area,” meteorologists wrote in a morning forecast. “A track more to the south and into the Gulf of Mexico would potentially keep the tropical moisture around the region longer.”
After Humberto, next name on the 2019 tropical cyclone list is Imelda.