Forecasters weigh tropical disturbance’s potential impact on Florida

NWS tropics

Next week’s weather in Florida is dependent on what happens with the tropical wave east of the Lesser Antilles. (Credit: NWS/ NHC)

The tropical wave designated Invest 99L has been tracked by the National Hurricane Center for almost a full week — since August 2, when it rolled off the coast of Africa.

It has waxed and waned since then, and various models have spun it up into a strong tropical storm or even a hurricane with some potential to slam the East Coast of the U.S.

The system struggled, though, and the GFS eventually dropped it. On Thursday, an interesting thing occurred: The respected European model (ECMWF) began forecasting development as it neared the Bahamas, and the ECMWF has continued to support at least a tropical depression or storm perhaps forming this weekend. It’s joined by the Canadian (CMC) and the Navy’s global forecast model.

What actually happens to the system will make a big difference to Florida’s weather next week, according to the National Weather Service in Miami. If the GFS is right and 99L remains a tropical wave, it’s likely to slide across the peninsula early next week. That would bring some needed rainfall to the area, but nothing more serious.

Tropical waves that do develop are usually pulled more toward the north, so if the ECMWF-CMC-NAVGEM scenario pans out, the disturbance — which would get the name Gert if it becomes a tropical storm — would probably stay east of the Bahamas and have few, if any, impacts on Florida.

National Weather Service forecasters said in their Tuesday discussion.: “Will keep an easterly wind flow over the area with the typical summer time weather pattern until the models become more in agreement on the strength and path of the disturbance.”

NOAA’s Weather Prediction Center shows more than 2 inches of rain falling across South Florida through next Tuesday, but much of that will come from an upper-level low near Puerto Rico that’s forecast to move into the Florida peninsula over the weekend.

Invest 99L, still east of the northwestern Lesser Antilles, did show some signs of pulling together on Tuesday, and the NHC bumped up development odds from 20 percent to 30 percent.

RECORD WATCH: Miami and West Palm Beach both tied record warm lows Monday with 82. Melbourne tied a record warm low with 81, and Vero Beach tied a record warm low with 80.

TS Franklin

Tropical Storm Franklin was moving over the Yucatan Tuesday. (Credit: NOAA)

TROPICS WATCH: The BIG QUESTION with Tropical Storm Franklin is: Will it become the season’s first hurricane? The official forecast by the National Hurricane Center has Franklin staying just under hurricane strength after it emerges off the coast of the Yucatan Peninsula and heads across the Bay of Campeche toward the coast of Central Mexico. It was forecast to make landfall as a 70 mph tropical storm, but just a slight uptick would make it a Category 1 hurricane, the season’s first.

As a result, a hurricane watch was posted for Puerto de Veracruz to Rio Panuco. The potential for hurricane development will become more clear Wednesday after it’s had some time over the warm Gulf of Mexico waters. Franklin is forecast to make its final landfall in the wee hours of Thursday morning.

Either way, it’s a formidable storm, with tropical storm force winds extending 140 miles from the center. Isolated rainfall amounts of up to 15 inches, triggering flash-floods and mudslides, are possible on Thursday across an area of the coast that spans 300 miles or more.

As we head toward mid-August in what experts say is going to be a very busy peak hurricane season, it’s interesting to note that outside of Invest 99L, Franklin is the only game in town for the Atlantic. None of the models are showing anything else spinning up over the next seven to 10 days, and the long-range GFS suggests systems coming off the coast of Africa will get eaten up through August 24, presumably by dry air.

This time of the year, however, weather can change quickly in the tropics.

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Author: jnelander

Freelance writer and editor

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