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."
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.
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.
800 AM: new Special Tropical Weather Outlook issued- There is a 60% chance of a subtropical or tropical depression forming in the central or eastern Gulf of Mexico this weekend. Heavy rain is the main threat for now. Full details: https://t.co/m9946DoYYi pic.twitter.com/EsjEYTvtiP— NHC Atlantic Ops (@NHC_Atlantic) May 23, 2018
Here is the 5-day rainfall forecast from @NWSWPC - much of the rain along the northern Gulf Coast and Florida is expected to be from the Gulf low. The next outlook will be issued by 8pm EDT. pic.twitter.com/MfJgstiMen— NHC Atlantic Ops (@NHC_Atlantic) May 23, 2018