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Posted at 12:37 PM ET, 06/24/2012

Tropical storm Debby lashing Florida Gulf Coast, copious amounts of rain possible


Satellite image of tropical storm Debby at noon on Sunday. (NOAA)

UPDATE, 7:45 p.m.: While the exact track of Debby remains uncertain, a sharp turn to the west now (towards Louisiana and east Texas) is less likely, whereas a continued northeast drift towards the northwest coast of Florida is more likely. Due to Debby’s slow movement, extreme rainfall amounts - as much as 10-20”+ in some locations along the west coast of Florida and Florida panhandle is a possibility. Serious flooding is a major risk with this storm.

From 12:37 p.m.: Tropical storm Debby, which formed Saturday afternoon in the eastern Gulf of Mexico, is giving forecasters fits about its future course as it drifts northeast at 6 mph and drenches the west coast of Florida. Situated 140 miles south-southwest of Apalachicola, the storm’s maximum sustained winds are 60 mph.

Some modest strengthening is possible over the next 48 hours, and Debby could become a minimal hurricane. But torrential rain, rather than wind, is likely to be Debby’s biggest hazard. Already, 2-4” of rain has fallen along parts of Florida’s west coast and a lot more may be on the way - although it’s not exactly clear where Debby is headed.

Link: Southeast U.S. radar

Computer models continue to be split on whether the storm will continue on a northeast track towards the Florida panhandle, or take a sharp turn west and threaten the central Gulf coast - anywhere from coastal Mississippi to east Texas, including the New Orleans area early this week.

The National Hurricane Center has essentially thrown up its hands and admitted it just doesn’t know where Debby is headed. It is playing a wait and see game, urging all Gulf coast residents to closely monitor forecasts.

“We must be ready to make a change of the forecast track at any time,” it said in its 11 a.m. ET discussion.

Regardless of its course over the next several days and whether it turns west, the storm is having meaningful impacts on the eastern Gulf of Mexico right now and conditions will deterioriate as the storm draws closer to land tonight. Tropical storm warnings extend from Suwannee River Florida to Morgan City Louisiana (see map, not as far west as New Orleans).

Heavy rain bands are lashing much of Florida’s west coast and torrential rain of 5-10” is possible from the central west coast of Florida to southeast Louisiana (although these kinds of heavy rains west of Florida are contingent upon the storm turning west, which is not guaranteed to happen).

Link: 3-day rainfall prediction from NOAA

Some of these areas (especially in the panhandle of Florida into Mobile, Alabama) experienced extraordinary rains less than two weeks ago, exacerbating the flooding risk.

Link: Obscene rain amounts drench Pensacola and Alabama Gulf Coast (PHOTOS)

In addition to possible flooding from heavy rain, coastal flooding is possible as the storm potentially raises the seas by several feet when it washes ashore. The highest storm surge (of up to 3-5 feet) will occur just east of where the center of the storm makes landfall, although it’s difficult to say exactly where/when that will be at this time.

Winds will also pose a hazard, with 40-60 mph sustained winds and gusts to 70 mph possible, especially right along the coast and during the heaviest feeder bands. Tornadoes are also possible embedded within the storm’s bands, especially east of the center. A tornado watch is in effect for a large section of central west Florida this afternoon through 8 p.m. this evening, including Ft. Myers, Sarasota, and Tampa.

Debby is the fourth named storm of the 2012 Atlantic hurricane season. When it formed yesterday afternoon, it became the earliest fourth storm to form on record.

Brian McNoldy, a professor of atmospheric science at University of Miami, offered this historical context and commentary:

On average, we only see the 4th named storm on August 23, and to have the 4th named storm form on June 23 shatters the previous record set by Dennis on July 5, 2005. This is truly a remarkable season so far!

By  |  12:37 PM ET, 06/24/2012

Categories:  Latest, Tropical Weather, U.S. Weather

 
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