Update 3:30 p.m.: Rain totals from the South Florida Water Management District show storms this morning dumped the most rain in Boca Raton and near Belle Glade.
Areas of coastal Boca Raton received 3.63 inches of rain, while areas southeast of Lake Okeechobee got as much as 3.55 inches.
The water management district said it lowered canals in anticipation of today’s heavy rainfall, which is part of a tropical wave and low pressure area over the Bahamas.
The system was given a 10 percent chance of tropical development by the National Hurricane Center as it moves up Florida’s coast.
Update 2:42 p.m.: Strong thunderstorms over Lake Okeechobee have triggered a marine warning until 3:15 p.m.
National Weather Service forecasters said a thunderstorm capable of producing waterspouts was 10 nautical miles south of Buckhead Ridge and moving south at 5 knots.
Update 11:30 a.m.: The National Weather Service has issued a flood advisory for areas of western Palm Beach County until 2:30 p.m.
Heavy showers associated with a tropical wave moving inland are expected to continue throughout the afternoon in Palm Beach County with two or more inches of rain expected.
Further south, Fort Lauderdale has already seen record rainfall today with more than 3.38 inches falling this morning.
An area of low pressure reaching from the Bahamas southwest into the Florida Keys is heading west-northwest toward South Florida today into tonight, bringing heavy showers and thunderstorms.
Forecasters at the National Weather Service are warning of rain rates of 1 to 2 inches per hour this morning with cells moving slowly inland from the coast of Delray Beach to Miami Beach.
Already, Fort Lauderdale International Airport has experienced 3.38 inches of rain, breaking a 2003 record of 3.35 inches. A flood advisory is in effect for southeast Broward County until noon.
“It’s quite the juicy atmosphere we have moving into South Florida,” said Arlena Moses, an NWS meteorologist in Miami.
The system carrying all the rain is sitting over the Bahamas. It was given a 10 percent chance of tropical development, but National Hurricane Center forecasters said that appears unlikely with heavy rain being the biggest impact to the Sunshine State.
Moses said the system is a tropical wave and low pressure trough that will move across through Friday.
“Some of the heaviest areas could see 5 inches of rain per hour,” she said. “Flooding may be a concern in the east coast metro areas and places with poor drainage.”
East of the northern Lesser Antilles, struggling Invest 99L is down to a 40 percent chance of development over five days. The development area for the storm keeps it east of the Bahamas and away from the U.S. coast.
The tropics came alive Wednesday with Franklin, the first hurricane of the Atlantic season, 99L and the trough of low pressure off Florida’s coast.
Franklin made landfall in mainland Mexico overnight as a Category 1 hurricane with 85 mph winds. Franklin is now a tropical storm but is expected to reach the Pacific in 24 to 36 hours where it could restrengthen.
The National Weather Service has issued a marine weather statement warning of strong thunderstorms in South Florida coastal waters, including Palm Beach County, that could produce waterspouts.
Robert Garcia, a meteorologist with the NWS in Miami, said some “tightening” spin in the storms has been seen.
An average of as much as 1.22 inches of rain overall is possible in Miami-Dade and Broward counties today, with less in Palm Beach County, according to the Weather Prediction Center. The cloudy weather will keep the temperatures below 90 in much of coastal Palm Beach County – the first day below 90 since Aug. 1 when the high reached only 83 degrees.
High pressure will begin to take over Friday, reducing rain chances and allowing temperatures to soar to 92 degrees.
Overnight lows are dropping back closer to normal after six days in the 80s. West Palm Beach tied its overnight heat record Wednesday when the temperature dropped to just 83 degrees.