Talking the Tropics With Mike: Dorian to impact the Lesser Antilles through Tuesday

Aug. 26, 2019 — The "Buresh Bottom Line": Always be prepared!.....First Alert Hurricane Survival Guide... City of Jacksonville Preparedness Guide... Georgia Hurricane Guide.

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Over the Central Atlantic.... tropical storm Dorian continues to move steadily westward with gradual structural organization (some banding + a central dense overcast at times) evident on satellite data. Gusty winds & squalls reach the Windward Islands of the Caribbean later Monday where tropical storm WATCHES & WARNINGS are in effect for some islands. The official NHC forecast does take Dorian to a hurricane while traversing the NE Caribbean but overall conditions (shear & especially dry air) look marginal which may very well result in weakening. As a whole, Dorian has generally trended west without gaining much latitude despite forecast's models insistence on a more poleward movement. A weaker system is likely to track more west vs. a more northward move. The overall marginal atmospheric conditions + possible land interaction should limit Dorian's intensity later in the week. It's worth noting that Dorian is a small/compact system & therefore may be susceptible to even small changes in its environment (shear/ dry air/land) resulting in wide intensity swings over a short period of time. In any case.... anyone with travel plans to the Caribbean through the week should stay up to date on the latest forecasts.

As for once beyond the Caribbean..... the GFS & European models have been consistent on weakening - or even dissipating - Dorian once deeper into the Caribbean &/or over/near Hispaniola (mountainous terrain). HOWEVER, the European has recently done an about-face with a relatively weak Dorian reaching the Florida coast over the weekend. It's not wise to just jump on a single forecast model run .... especially such a drastic change from many previous model cycles... but it's something to keep an eye on. The UKMET model is showing a similar trend (but has not done particularly well w/ wave '98-L' - too strong, too far west).

So.... the bottom line is stay up to date on the latest forecasts for the Caribbean, Fl. & Southeast U.S. this week into the upcoming holiday weekend.

IR satellite:

Visible satellite:

Tropical wave '98-L' is now fully over the Western Atlantic east of the Carolina's. Thunderstorms continue to pop over the eastern & southeast part of a broad, weak circulation. Rip currents along area beaches are the biggest threat from the Carolina's to Chesapeake Bay.

No change in the movement forecast. An upper level trough to the north has become the main steering mechanism taking the low - could become "Erin" - well east of the U.S. east coast & west & northwest of Bermuda. Other than a rip current risk along the U.S. east coast, so major direct impacts are expected despite what is likely to be a strengthening tropical system this week.

Spaghetti model forecasts for '98-L' & t.s. "Dorian":

An examination of dust over the Central & Eastern Atlantic shows a continuation of a good deal of dust over the Central & Eastern Atlantic as well as parts of the Caribbean. Dorian will encounter much of this dry air in the coming days.

2019 names..... "Erin" is next on the Atlantic list (names are picked at random... repeat every 6 years... historic storms are retired (Florence & Michael last year):

East Atlantic:

Mid & upper level wind shear (enemy of tropical cyclones) analysis (CIMMS). The red lines indicate strong shear of which there is plenty across the Atlantic at the moment:

The Atlantic Basin:

Water vapor imagery (dark blue indicates dry air):

Deep oceanic heat content:

Sea surface temp. anomalies show a warm Gulf of Mexico, Central & Northwest Atlantic while the "Main Development Region" (MDR) remain cooler than avg. along with parts of the Central Caribbean.....