This weekends weather. Worth a look.

I received this last night-

Hi everyone,

Some of you may have noticed the afternoon wind surges over Florida Bay and around the upper Keys during the last few days. I have attempted to describe this phenomenon with my version of an "infographic" (attached). Basically, when the prevailing winds are from a westerly direction, this usually means that a high pressure area is located to the south and a low pressure area is located to the north. During the afternoon in such a case, the south Florida mainland heats up more than the Florida Keys and adjoining waters, and the heated air column lowers the pressure at the surface, in effect creating a larger pressure difference from north to south. This pressure difference is concentrated most over Florida Bay and the upper Keys during the late afternoon, and the surface breezes respond accordingly by freshening. The five-day graph of wind speed at Molasses Reef shows the wind speed cycling up in the afternoon and down at night, whereas the graph for Pulaski Shoal (Dry Tortugas) shows relatively light breezes at all hours.

You should see the afternoon surge around the upper Keys once again tomorrow (Saturday) afternoon, prior to a northerly wind shift setting in across all of southern Florida tomorrow night. You may even detect a slightly less humid air mass with perhaps even a few degrees of cooling Sunday morning. Cold front? I would call it more of a "cool" front, nothing like the cold winter blows of December, January, and February, but still, a sign that autumn is here.

Have a great weekend!

Chip K.

Kennard "Chip" Kasper
Senior Forecaster-Marine Program Meteorologist
NOAA/National Weather Service
1315 White Street
Key West, Florida 33040


  • sugarloafersugarloafer Posts: 195 Deckhand
    makes sense..................should be a a specific situation type where there low pressure [cloudy usually] to north [central n north fl.] but still sunny in south florida.

    sun warmed south florida would produce a 'heat low' of some level of strength
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