We should get impacted by a tropical wave this weekend, the first of the season for us. Its rain could arrive as early as Friday night. Waves are notoriously fickle to forecast, as they can grow quickly or fall apart just as fast. If this one holds, the downpours could stick around through Monday.
The satellite image shows a line of clouds across Jamaica, Eastern Cuba, and Western Haiti. This is the leading edge of the wave.
The water vapor image detects how much moisture there is at the upper levels of the atmosphere. It’s like looking into a sponge and seeing how much water it is carrying. The green over Eastern Cuba shows the wave is carrying plenty of moisture that may reach the rest of the island, NW Bahamas, and South Florida in the days ahead.
High pressure has winds coming in from the ESE. This will push the wave and the moisture to the northwest. The European model is very aggressive and shows plenty of rain across the region as early as mid-afternoon. Other models suggest a later evening start.
By Saturday, the wave is near Western Cuba with a good chance for downpours across South Florida. Some of the rain could be heavy leading the ponding of water on roadways.
On Sunday, the wave pushes into the Gulf of Mexico, but trailing moisture will still be present for another good chance for rain. The moisture may even stick around thru Monday.