As of the 8am AST advisory, Irma is now a powerful category 5 hurricane with sustained winds of 175mph.
The storm has been moving in a steady west direction most of yesterday and last night. The expected WNW turn has not yet begun. The longer it continues on this track, the greater the risk to the northern leeward islands. At any rate, the islands should expect to see severe conditions from this storm.
There is still hope that the impact on the US Virgin Islands and Puerto Rico will not be disastrous, but it would not take a very large shift south for the north side of Puerto Rico to be in the eyewall, so interests there also need to be prepared for an extreme impact.
Further down the line, Hispaniola is more likely than Puerto Rico to avoid a severe event, but the north coast of Cuba and South Florida (and points beyond but I’m sticking to a five day timeframe here) are at high risk.
The most reliable models continue to show a WNW track near or slightly over Cuba with a sharp north turn at the end of the forecast period into South Florida. There is some spread, with the European ECMWF model being slightly west of the American GFS model.
Here are the ensembles of the ECMWF for last night’s run:
and here are the GFS ensembles for the morning run:
Governor Scott has declared a state of emergency for the entire state of Florida and this was not an over-reaction.
I will try to update and reply to comments as I can today, but I need to spend much of the day making preparations. Good luck to all in the islands and here in the southeast US.
Tuesday, Sep 5, 2017 · 3:39:51 PM +00:00
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jrooth
Sorry to be late with this update, I’m in an out trying to get things ready. 11am advisory has 180 mph sustained winds. They made a point of saying that was not measured in the NE quadrant so wind may be even a bit higher than that.
This is getting into historic storm category for the Atlantic basin. Not quite in Gilbert or Wilma territory yet but getting close.
Tuesday, Sep 5, 2017 · 4:48:30 PM +00:00
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jrooth
I’m getting very nervous to the leeward islands, especially Barbuda and Anguilla and the British Virgin Isles, but also the next set southwest of them. Irma is not gaining quite as much latitude as expected, and even a tiny south shift can be the difference between bad and catastrophic.
Puerto Rico is also gradually getting more under the gun. I’m still optimistic that the center stays offshore to the north, but it may be a very close thing.