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Sunday, Sep 23, 2018
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Forecast: Relative calm before Invest 90L threatens to deluge Tampa Bay this weekend

ST. PETERSBURG — While rain chances will decrease over the next two days, it is only a relative calm before a broad low pressure system moves into the Gulf of Mexico, producing strong storms across an already drenched Tampa Bay for Memorial Day weekend.

Invest 90L now has a 60 percent chance of developing into a tropical system in the next five days, according to the National Hurricane Center. If the system does develop further, it could become tropical storm Alberto, but forecasters at the National Weather Service say that a storm like that would be unlikely and unstable.

"Gulf waters just can’t sustain a tropical storm," said Paul Close, a meteorologist for the weather service. "The Gulf isn’t warm enough this time of year."

RELATED: Rick Scott issues warning as potential tropical system approaches gulf

Even so, Close said Tampa Bay should expect plenty of rain over the Memorial Day weekend.

Forecasters say about 2-4 inches of rain could fall over the next four days, with the heaviest downpours on Friday and Saturday.

EXTENDED FORECAST: The 10-day outlook for the Tampa Bay area

Monday’s afternoon high will reach 88 which may spurn scattered showers around the bay area

Thursday will look similar with a relatively dry morning, until afternoon highs mix with the coastal breeze. Expect to begin seeing heavier downpours on Friday.

The biggest concern over the weekend is local river flooding as recent storms have prompted multiple warnings this week.

A flood warning remains in effect until Wednesday afternoon for the Alafia River in Lithia. On Tuesday night, it had risen above flood stage at 13.7 feet but is expected to recede to below the 13.0 flood stage by the morning.

Forecasters warn that folks near the rivers should monitor the situation closely as conditions are expected to deteriorate over the weekend.


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