Sunday, August 28, 2016

NEW Tropical Depression #9

The area of disturbed weather known as Invest 99L, which we've been following for the last week, has finally organized. It is now Tropical Depression 9, and its still full on uncertainties.

Satellite imagery shows plenty of rain across the Straits just sitting there. Last Friday most models were shoving this rain over us this weekend, but that didn't happen.

This system has been a frustrating nightmare to forecast. First because of its indecisiveness and then because of its proximity to land and South Florida.

It has spent most of the weekend causing torrential rainfall over Cuba causing flooding there.

Earlier on Sunday, a recon plane went in to investigate the disturbance and, unlike other missions where no defined center of circulation was found, they hit pay dirt on this one.  NHC has classified it as Tropical Depression #9.

How strong will it be?
The models which we rely on heavily for guidance have been less than stellar with this feature. The most reliable models, the GFS and the ECMWF (European), have been at odds and mostly off. They have each called for intensification or weakening, or growth and dissipation at one time or another since last week.

The one thing the models were missing last week was a good starting point. No good starting point meant no good ending point, so they were giving us educated guesses. This time around they've got a good fix. So what are they saying now?  Still murky.

For the time being, strong upper level winds should hamper its growth but in around 48 hours the shear will relax allowing it to get a little stronger. BUT, its not that simple, the ECMWF says the depression should fall apart all together soon... with the GFS showing strengthening in 4 to 5 days. Most other models are being aggressive with its development. NHC is keeping its future strength as a Tropical Storm until the models give us more to work with. If it develops into a storm it will be called  "Hermine".

Where is it going?
Here too there is plenty of uncertainty. High pressure over the Atlantic will push it west into the Gulf, but that high should weaken and retreat in about 48 hours.

This will allow the system to stop and head north over the Gulf of Mexico.

What interaction will the warm waters of the Gulf have on its intensity is not too clear, but past history indicates a good window for strengthening.

In about 4-5 days a front out of the Nation's midsection dives into the Gulf pushing the system back to Florida.

This means, the entire state could see a huge drenching from tropical moisture dragged up from the Caribbean Sea.
We might have lucked out here in South Florida this weekend with drier conditions, but our luck may run out in the days ahead as all that moisture gets pushed here.

We'll keep you posted.

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