Rainfalls Stall In May; Air Remains Too Dry

TAMPA - Rainfall around the Tampa Bay area was doing pretty well this year, racking up a surplus of 3.5 inches through April.

Then came May.

At 0.73 of an inch, rainfall at Tampa International Airport so far this month lags almost 1.5 inches below normal, and the deficit has chewed away nearly half of the extra rain accumulated in the first four months of 2008.

Plus, temperatures this month are averaging a couple degrees above normal.

West Central Florida is entering the time of year when skies are clear, temperatures high and afternoon summer rains remain weeks away.

The dry weeks have had an effect on lake levels. In Pinellas, Pasco and Hillsborough counties, lakes dropped almost 0.4 of a foot in May and are nearly 2 feet below the lowest level expected for this time of year.

The low water levels have created a trap for hundreds of fish and a bonanza for scavengers near Lake Thontosassa, where a creek leading from the lake has become a large pool.

The creek normally flows from a Southwest Florida Water Management District control structure that is closed to keep water in the lake.

The water district did release some water from the lake into Flint Creek during the winter when rain was above average, said Robyn Felix, district spokeswoman.

Since rain diminished in late April and all but disappeared so far this month, only a small amount of water gets past the structure, she said.

"It's closed now to maintain the level of the lake," Felix said.

The lake level needs to rise about a half-foot before water will flow into the dried creek.

"Until it rains, there won't be any flow in the creek," Felix said.

The weather isn't ready yet to provide any relief. Typically, the regular afternoon thunderstorm pattern gets rolling around the second week of June.

By the last week of May, occasional thunderstorms begin to appear.

But now the air remains too dry, said Paul Close, National Weather Service meteorologist.

There is not enough moisture above 10,000 feet to allow thunderstorms to grow. Moisture needs to be plentiful 20,000 or 25,000 feet high.

"Then you start seeing some activity," Close said.

Fronts such as the one that arrived over the weekend have been dragging in too much dry air for humidity to build. Each front brings another dose of dry air and delays the rainy season.

For our summer rains to begin, what's called the Bermuda High needs to set up in the Atlantic to provide winds from the southeast that are laden with moisture. Also, the Gulf of Mexico needs to get a few degrees warmer.

Gulf water needs to reach the low 80s and is hovering now in the high 70s, Close said.

There's a chance the parade of fronts could be over. Forecast models indicate the next one heading toward the Tampa Bay area later this week may stall to the north, Close said.