The past five hurricane seasons have all started early with preseason tropical systems in May or April and this year we may see the trend continue.
Two forecast models develop a tropical storm north of the Bahamas this weekend with one becoming a long lasting whirl of clouds east of Florida.
Even though the Atlantic hurricane season runs from June 1 through November 30, there is no hard fast rule bounding tropical cyclones to those months; although rare, at least one named system has developed in each month of the year.
Typically only 3% of tropical storms and hurricanes form outside the six month hurricane season. Cooler water under 80F limits hurricane activity.
One of the ingredients needed to fuel hurricanes is warm sea surface temperatures.
Coincidentally, each preseason storm over the past five years has coincided with the planet’s five warmest years. All have occurred since 2015 using data from 1880 to 2019 according to NOAA National Centers for Environmental information.
The past five years have been the hottest five on record for the second year running.
Bottom line...if the water is warm, hurricanes will spawn year round just like in the eastern Pacific.
The GFS model is continuing the trend for an early May tropical storm this weekend which would be uncannily similar to last May, when Subtropical Storm Andrea formed southwest of Bermuda the week before Memorial Day.
In 2018 Tropical Storm Alberto hit the Florida Panhandle on Memorial Day.
In 2017, Tropical Storm Arlene formed in April and 2016 had both Tropical Storm Bonnie in late-May and Hurricane Alex, the second known January Atlantic hurricane on record.
In 2015, Tropical Storm Ana made a Mother's Day landfall becoming the second-earliest on record.
Does an early start mean an active hurricane season?
Typically an early start does not imply an active hurricane season but ever since 2016, each season has been well above average with 16 or more named storms.
The experts weighing in on this year's long range seasonal hurricane forecasts all agree this year will be above-average, maybe even extremely active.
Almost all of which are forecasting an above-average -- more than six -- hurricanes this season, which begins June 1.