What Jacksonville’s record heat to the year means for hurricane season

Record heat and stormy days could jump start hurricane season... again

Warm water played a part in 2019 when subtropical storm Andrea became the fifth consecutive year with a preseason storm. Record heat is driving the trend over the past 50 years for storms to form earlier. (NOAA)

JACKSONVILLE, Fla. – Staggering record heat has put Jacksonville in first place for the warmest start to the year on record.

The average January 1 through April 30 temperature was 65.1 degrees -- the hottest since records were established at Jacksonville International Airport in 1971.

There wasn’t much of a winter, with less than a handful of freezes and spring has witnessed several 90 degree days.

Only nine days so far this season have seen below-average temperatures. March was especially brutal with five days at 90 or above.

The warmth fueled double the number of thunderstorm days, totaling eight. That was the third most active on record.

Will the warmth jump-start an active hurricane season?

Warm air heats the ocean which can provide a boost to storm strength and activity during the hurricane season.

Water temperatures offshore Jacksonville are 70 degrees and currently cooler than average due in part to offshore winds pushing away warm surface water, and that’s a good thing.

SST over the past 7 days are cooler than average and slightly cooler (<-1F) than this time last May. (tropical tidbits)

But fluctuations can occur over spans of days and the upcoming first week in May will bring back to back 90 degree days for most of it.

During the March and February heat waves, sea surface temperatures (SST) climbed above 3-5 degrees warmer than average in the trend graph below.

Water temps offshore JAX are 5 degrees warmer than last year during March. (wjxt)

June through November marks hurricane season, when SSTs are typically over 80 and can support tropical cyclones.

Warm water can kick up storms before June 1. Just last year Subtropical Storm Andrea developed on May 20, before the start of hurricane season. It marked the fifth consecutive year with a preseason-named storm following Hurricane Ana in 2015, Bonnie in 2016, Arlene in 2017 and Alberto in 2018.

If recent history repeats, we will need to watch and see if 2020 brings another early May storm.

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