Update 2 p.m.: The National Hurricane Center has dropped the chances of a tropical wave becoming a cyclone to 70 percent over the next five days.
The system still lacks a closed circulation and the strongest winds have dipped below tropical storm force, according to a 2 p.m. forecast.
While a 70 percent chance is down from the last advisory, which was giving the system an 80 percent shot of becoming a tropical storm, it’s still high and forecasters said there is a chance for significant development over the next day or so as it moves closer to Florida.
Update 11:30 a.m: National Weather Service forecasters in Miami are pointing to late Saturday as the time when South Florida will begin feeling impacts from the tropical wavenow nearing the Turks and Caicos.
Pablo Santos, meteorologist in charge in Miami, told emergency managers during a special storm briefing this morning that they should be prepared for anything from a tropical wave to a weak Category 1 hurricane as forecast uncertainty continues.
“It could be just a wave, which could still bring serious flooding, to a hurricane. We cannot rule that out,” Santos said. “I know you want answers to all these questions, but right now the best we can tell you is if we end up getting impacted, the window of concern is late Saturday through Monday.”
Santos stressed that forecasters still struggle with predicting the intensity of tropical cyclones, which is a concern when it’s possible this system could form just off the coast of Florida.
“What I can tell you is the conditions preventing this system from evolving will be gradually lessening over the next day or two,” Santos said. “If it were to intensify, it will do so as it moves closer to us.”
Rain may also be an issue. Santos said up to seven inches could fall in extreme South Florida over a five-day period. Palm Beach County could see up to five inches.
The U.S. Army Corps of Engineers decided this morning not to change discharges from Lake Okeechobee into the St. Lucie and Caloosahatchee estuaries. The lake was 14.67 feet above sea level today, which is down 0.08 feet over the past week and higher than the Corps would like during the rainy season.
While rules regarding the lake say the releases could be cut back because of more normal precipitation, the Corps said the possibility of a storm gives them the power to continue at the current levels.
“Given the risk of a tropical system dropping a lot of rain in South Florida, we need to get additional water out of the lake,” said Candida Bronson, acting operations division chief for the Corps in Jacksonville.
Mike Resto, Palm Beach County emergency management specialist, said he understand how the lack of certainty can be frustrating to people.
“We really want to inform them correctly and sometimes it’s hard to tell them that we’re not sure,” Resto said. “It’s not because we don’t know what we’re doing or the weather service doesn’t know what it’s doing, it’s just that it’s weather and it’s rarely 100 percent.”
National Hurricane Center experts are also fretting over 99-L’s forecast.
Update 8 a.m.: The tropical wave making a beeline toward Florida is struggling this morning, but the National Hurricane Center said there is still an 80 percent chance it could become a tropical cyclone by Monday.
Forecasters said the system continues to lack a well defined center, which would classify it as a tropical system.
It doesn’t have much chance of forming in its current location, which is experiencing some robust wind shear, but once it heads over the warmer waters of the Bahamas it could become better organized.
The National Weather Service in Miami said something could reach South Florida, either as a tropical system or just stormy weather, late Saturday night through early Monday.
The system was blowing tropical storm force winds Wednesday as it whipped the northern Leeward Islands.
Further away in the Atlantic, Hurricane Gaston formed overnight, with the National Hurricane Center’s 5 a.m. advisory noting wind speeds of 75 mph and a central pressure that had dipped to 988 mb.
The hurricane, the third of the 2016 storm season, is no threat to land at this point.
Still all eyes are on Invest 99-L, which has seen little change since yesterday.
This system was producing gale-force winds over water north of the Virgin Islands early this morning.
But its lack of a defined center failed to earn it tropical status by the hurricane center. If it becomes a named storm, it would be Hermine.
Although upper-level winds are only marginally conducive for development, the center believes the system could still become a tropical cyclone during the next couple of days.
A NOAA P3 hurricane hunter aircraft and crew are investigating the storm this morning on a mission that left Tampa around 2 a.m. An Air Force Reserve hurricane hunter is also scheduled to investigate the system today.
While the hurricane center said it is still too early to speculate what the system heading to Florida will do, it did have tropical storm force winds yesterday and could be moving into areas with less wind shear and warmer water.
Robert Molleda, warning coordination meteorologist for the National Weather Service in Miami, said there is a chance if the storm intensifies swiftly, that forecasters will skip storm watches and go right to warnings.
“With the environment not being conducive until it gets close to us, it could develop right offshore,” he said. “It’s a more complicated situation with the system not being developed and there is a lot of uncertainty.”
Jeff Masters, co-founder of Weather Undergrund and a former NOAA hurricane hunter, called the system “huge and powerful” late Wednesday, but said that size could hurt its ability to organize. Masters said a drop in wind shear today could allow the system to form, but models are still in disagreement with how strong it could get.
“Two of our three reliable models for predicting tropical genesis, the ECMWF and UKMET, continued to show development of 99L into a tropical storm by Friday in their latest 12Z Wednesday runs,” Masters wrote in a blog late Wednesday. “These models brought 99L across or near South Florida on Sunday and into the Gulf of Mexico, with a second landfall occurring on the Florida Gulf Coast on Tuesday. Our other reliable tropical cyclone genesis model, the GFS, continued to insist that 99L would not develop through Sunday.”