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Tropics stay quiet as moisture surges toward South Florida

July 14, 2020, satellite image of the tropics.
July 14, 2020, satellite image of the tropics. (CIRA/RAMMB)

The dominant feature from Africa across the tropical Atlantic is Saharan Dust. A denser part of the plume has moved over South Florida, which is making the skies quite milky and should limit the number of thunderstorms that develop.

This is a continuation of the pattern we’ve had most of the summer. When there is a lot of dust over us, there are fewer thunderstorms and it’s extra hot and humid. When there is a little less dust, the storms form and they are extra strong. The ones that form have had to punch through the dust. They have to be something of a heavyweight to do that.

In addition, there has been little or no ocean breeze.

A change is finally coming in the weather pattern. Beginning on Thursday, a high-pressure system will build over the Atlantic, which will switch our wind direction so it blows in off the ocean. This general change in the flow of air will bring in tropical moisture, which we should notice beginning Friday.

The moisture surge will come from a combination of a tropical disturbance that is now approaching the Caribbean islands and moisture east of the Bahamas, which can finally get blown our way. The role of the disturbance will mostly be to help increase the ocean breeze.

More night and morning thunderstorms, somewhat cooler high temperatures and a cleaner sky should be the result of this change in the weather. The rain and wind should wash out much of the dust.

Long-range computer models into next week show Saharan Dust continuing to push across the Atlantic, with only the upper fringes of it affecting Florida. There still appears to be enough dust to keep the tropics quiet for now.

Some well-developed tropical disturbances are forecast to move off Africa next week. But the dust and developing strong Atlantic high-pressure system are forecast to keep them well south and unable to develop.

No tropical development is expected through this week.


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