Posted by: coastlinesproject | August 28, 2015

Tropical Storm Erika. Courtesy Bill Ryan.

Here’s the 2 pm NHC update, the next one is at 5 pm.

LOCATION…16.5N 63.8W
ABOUT 160 MI…255 KM W OF GUADELOUPE
MAXIMUM SUSTAINED WINDS…45 MPH…75 KM/H
PRESENT MOVEMENT…W OR 280 DEGREES AT 16 MPH…26 KM/H

The NHC forecast track brings the center of Erika over Grand Bahamas Sunday morning but, as discussed below, there is a large cone of uncertainty. Erika is expected to begin strengthening sometime late Friday but remain at tropical storm strength through Saturday.

Erika is a bit of a hot mess at this time. There is considerable convection occurring, denoting potential strength, but the circulation is very ragged denoting weakness. Erika is heading into a region near Hispaniola where wind shear has been increasing, so no significant strengthening is expected for the next 24 hours. If Erika tangles with the mountains of Hispaniola it will weaken significantly.

After Friday, though, bets are off. The model track forecasts, fairly stable over the past few days, have now become higher variable. Below is an example from the GFS Ensemble model (GEFS). It shows two solutions (as the blues singer says: “if it ain’t one thing, well, it’s two”), one moving along the FL coast and the other into the Gulf. Neither solution is especially palatable. The warm waters off FL will serve to re-invigorate Erika, and the Gulf of Mexico is exceedingly warm. The best case is for Erika to just come on into FL and get it over with. The trend of the model solutions over the past few runs is to the right which makes the northerly path more likely at this time. However, this is still very much up in the air.

at201505_ensmodel.gif
“Do
not fear mistakes. There are none.” Miles Davis

 

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