Over the past month I've been pointing out hot and dry weather conditions here in southwest Florida. Fire danger was in the very high category with several brush fires burning and drought conditions were severe for much of the area. In the course of a couple weeks that has changed.
We can thank that to the start of rainy season, but how do we really know when rainy season starts? It usually starts in either mid or late May and ends in mid October. There are a few factors to look for when determining the start of rainy season.
First we see cold fronts not pass through or even reach southwest Florida. That occurred during the early part of May. Next we look for daily showers and thunderstorms to form along the a line where the Atlantic breeze converges with the Gulf breeze. Lastly it remains humid both day and night with temperatures and dew points in the upper 60s and 70s. The latter two conditions have occurred the past couple weeks.
Just a few weeks ago both Page Field in Fort Myers and the Naples airport were between 4 and 6 inches below average since January 1st. With the several inches of rain that has been falling both locations are now above average in rainfall in 2020.
In fact, a flood watch is in effect for all of southwest Florida. Some of our region will be in this watch until Saturday afternoon due to an abundance of tropical moisture coming in to southwest Florida from the west. This moisture combined with an upper level disturbance will support showers and thunderstorms through the first part of the weekend. Several inches of rain could cause flooding of low lying and poor drainage areas as well as ponding on roadways.
Forecasters at the National Weather Service in Miami will officially determine the start of rainy season soon, but I think it's safe to say that rainy season has begun in southwest Florida.