Potential Tropical Cyclone 18 heads toward Florida

Update: 4:30 p.m.: Potential Tropical Cyclone 18 has been identified by the National Hurricane Center, which began issuing advisories at 5 p.m.

The system, which would be named Philippe if it becomes a tropical storm, is expected to drench South Florida tomorrow with up to 4 inches of rain.

The hurricane center began designating potential tropical cyclones this year for storms they feel confident will develop, but may not do so until very close to land.

Tropical system set to douse South Florida this weekend

“Whether it develops or not, the impacts will remain the same,” said Chuck Caracozza, an NWS meteorologist in Miami. “The main threat is the potentail for heavy rainfall and possible flooding.”

Check The Palm Beach Post radar map.

Since 1851, only 8 percent of hurricane seasons have reached the 16th named storm, according to Brian McNoldy, a senior research associate at the University of Miami Rosenstiel School of Marine and Atmospheric Science.

The last year a P-storm was named was 2012.

Update 1:20 p.m.: The National Hurricane Center has increased the chances that a tropical disturbance southwest of Florida will become a depression or storm to 80 percent.

In an afternoon update, forecasters said the area of low pressure over the northwestern Caribbean Sea is beginning to organize, and that a tropical cyclone is “likely to form later today or Saturday.”

Tropical storm watches and warnings may be needed for the Cayman Islands, central and western Cuba, and the central and northwestern Bahamas later today.

An Air Force Hurricane Hunter is en route to the system to investigate.

Regardless of development, South Florida is expected to see rain amounts up to 4 inches with the system beginning late tonight through Saturday.

Previous story: A persistent area of showers and thunderstorms between Jamaica and northeast Honduras became better organized overnight, leading the National Hurricane Center to increase its  chances for tropical development to 60 percent.

The system, which would be named Philippe if it gained tropical storm status, has only a small window for development before a cold front rushes down to disrupt its attempt to organize.

Regardless of tropical development, forecasters expect heavy rain from the system to hit the Cayman Islands, Jamaica, and portions of Cuba, before moving further north to the Keys and South Florida.

The National Weather Service in Miami said the best chances for rain for South Florida are Saturday afternoon and evening, with showers beginning late tonight.

That's not good news for this year's Moonfest in downtown West Palm Beach, which is scheduled for Saturday.

“Potential for 3 to 4 inches of rain is increasing, with localized heavier amounts and flooding possible,” forecasters wrote this  morning. “Also, there will be enough instability to support scattered thunderstorms, mainly Saturday afternoon and evening, as another frontal boundary approaches South Florida from the north.”

A slight risk for excessive rainfall that could cause flooding was issued by the Weather Prediction Center for areas from the Keys through parts of the Treasure Coast.

South Florida Water Management District officials said Thursday they were lowering canals to in preparation for heavy rain.

Areas from north of Lake Okeechobee through Miami-Dade County have been inundated with rain this wet season with Lake Okeechobee sitting at 16.95 feet above sea level on Thursday. That’s more than a foot above the 15.5 feet that the Army Corps of Engineers is comfortable with.

Rain accumulation from 8 a.m. Friday through 8 a.m. Sunday.

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