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The tropics are expected to stay calm into midweek, at least

Sept. 25 satellite image of the tropics.
Sept. 25 satellite image of the tropics. (CIRA/RAMMB)

It’s like a knob was turned with the change of the season, and hurricane season switched over to a fall pattern. About the end of September, the mechanisms that generate storms over the eastern Atlantic gradually shut down, and the potential for a storm forming in the Caribbean or Gulf of Mexico increases. That’s happened, but there was nothing gradual about this year’s changeover.

Suddenly there’s hardly a cloud swirl worth mentioning near Africa, and dry air is pushing farther south again in the eastern Atlantic. Over the Gulf and Caribbean, we can see the mechanism trying to develop that can move storms north out of the tropics. But so far, the stars are not aligning, and the disturbances are stuck to the south.

A cell of high pressure is located from Florida into the southern Gulf and western Caribbean. That cell is going to shift west and cover the southern Gulf, effectively bottling up the potential tropical disturbances near and over Central America.

As dips in the jet stream come along over the U.S., the dip has to be able to reach the disturbances to lift them north, or to at least grab their moisture. With the high pressure in place, that won’t happen.

Over the next few days, the orientation of the high will also change, which will improve the daily weather across South Florida. So for now, the high is our friend.

Ex-Beta is petering out over the South, but is still spreading some heavy rain to the east of what’s left of the circulation center.

No tropical development is expected into the middle of next week, at least.


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