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What does La Niña mean for Florida? Another warm, dry winter.

 
Forecasters predict warmer temperatures across the South this winter, a result of La -ina conditions. It would be Florida's seventh warmer-than-average winter in a row. [Courtesy National Weather Service]
Forecasters predict warmer temperatures across the South this winter, a result of La -ina conditions. It would be Florida's seventh warmer-than-average winter in a row. [Courtesy National Weather Service]
Published Nov. 10, 2017

ST. PETERSBURG — Florida has had six warmer than normal winters in a row, and in all likelihood, it's about to get its seventh.

That's because La Niña conditions have developed, the National Weather Service's Climate Prediction Center announced Thursday morning.

La Niña is a weather pattern in which cold water temperatures in the Pacific Ocean cause the jet stream to shift north and calmer, dryer air to sit in the South during the winter.

The conditions have a 65-75 percent chance of remaining in place at least through the winter, according to the weather service, bringing the northern part of the country more storms and cold weather, but not the South.

Forecasters predict the pattern to be weak, as it was last year, but Florida typically feels the impacts strongly, said David Zierden, a climatologist at Florida State University. And La Niña is set to strengthen, peaking between February and April, said Rick Davis, a senior forecaster with the weather service in Ruskin.

What that means for Florida: half as much rainfall as normal between now and March and temperatures 2 to 4 degrees warmer.

It could certainly still get cold at times, meteorologists say. Typically, Davis said, a Tampa Bay winter sees a cold front every 3 to 6 days.

"There could still be individual cold snaps with Canadian cold air, but the chances of those occurring as frequently are reduced," he said.

At the same time, Florida is already experiencing a long heat streak. The Sunshine State has been warmer than average for 20 straight months, and for 31 of the last 32.

"I think this three-year trend … is certainly partly a result of climate change," Zierden said.

But La Niña has the bigger impact on predicting this winter's weather.

Between November 2016 and January, statewide temperatures averaged 65 degrees, 4.7 degrees above normal. In Tampa specifically, it was even hotter — 69 degrees, 5.8 degrees warmer than normal.

In addition to staving off the cold, the pattern will likely reduce rainfall, exacerbating an already dry time of year in Tampa Bay.

Long stretches of dry days could bother those with allergies, Davis said, by allowing allergens or pollutants to hang in the air.

"A lot of the time, when we get the rain, it washes those out of the air and into the rivers," he said.

And in Tampa Bay, the nation's lightning capital, that increases the risk of wildfires.

Davis warned residents to prepare for potential "increased fire danger" in the spring. Trimming vegetation around the home can help prevent the spread of wildfires, he said.

However, what Zierden called "a robust wet season" featuring Hurricane Irma should provide some protection from drought.

"We're in a good spot," he said.

Contact Langston Taylor at ltaylor@tampabay.com.
Follow @langstonitaylor.