Somebody forgot to tell a certain ocean that the hurricane season doesn’t start for another month.
On Tuesday, South Florida woke up to heavy rain, thanks to a messy system swirling over the northwest Caribbean, the Bahamas and Florida. National Hurricane Center forecasters are giving the system less than a 40 percent chance of organizing into at least a depression as it moves up the Atlantic Coast over the next five days. But it does open up the rare possibility of a named storm coming weeks before the hurricane season officially kicks off on June 1.
“The atmosphere doesn’t care when June 1 is if the oceans are conducive to making a tropical storm,” said Jeff Masters, director of meteorology at Weather Underground.
Warmer-than-normal ocean temperatures — about three to five degrees above normal — are helping to fuel the storm, Masters said. The warm water could combine with energy from colliding cool and warm air to create what meteorologists call a subtropical system. Tropical systems during the hurricane season feed off of warm water alone.
Whether the storm strengthens depends on where it slows. If it “sets up shop over the core of the Gulf Stream current,” where water is warmer, it could build, he explained.
A hurricane-hunter plane on Wednesday is scheduled to investigate the system, which would be named Ana if it develops sustained winds of 39 mph or more.
For South Florida, the system is mainly a rain threat, although downpours should be tampering off Thursday, with the heaviest squalls expected to stay offshore, said National Weather Service meteorologist Chuck Caracozza. Rain should also subside as the system slowly moves north.
Seas will also remain rough, he said. The chop in Miami-Dade and Broward counties is forecast for three to five feet, with a strong chance of rip currents. Palm Beach County is expected to be slightly rougher at five to seven feet, Caracozz said.
While not unheard of, preseason storms are rare, with only 24 tropical storms or hurricanes forming in May since 1851. In 2012, Beryl blossomed into a tropical storm off North Carolina before it moved Southwest, growing stronger and striking Northeast Florida. The storm was blamed for at least three deaths in South Carolina and Cuba.
This year, the first early forecasts are calling for another quiet hurricane season. Colorado State University’s Tropical Meteorology Project predicted seven named storms, including three hurricanes in 2015. The forecast called for just one major hurricane, far short of the 30-year average for 12 named storms and three major hurricanes.
NOAA’s official forecast is scheduled to be announced May 27, Hurricane Center spokesman Dennis Feltgen said.