Tuesday, September 5, 2017

Peering into the Eye of a Monster: Hurricane Irma Now Catastrophic Category 5 Storm; 2nd Strongest Ever Atlantic Basin Tropical Cyclone

Staring into the eye of a spinning monster ...



In case the above embedded tweet vanishes, here is a YouTube clip:


The GOES-16 resolution is incredible -- and perfect for a monster storm such as this one.

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000
WTNT31 KNHC 051742
TCPAT1

BULLETIN
Hurricane Irma Intermediate Advisory Number 26A
NWS National Hurricane Center Miami FL AL112017
200 PM AST Tue Sep 05 2017


... POTENTIALLY CATASTROPHIC CATEGORY 5 HURRICANE IRMA HEADING TOWARD THE LEEWARD ISLANDS ...

... PREPARATIONS SHOULD BE NEARING COMPLETION IN THE EASTERNMOST LEEWARD ISLANDS ...

SUMMARY OF 200 PM AST ... 1800 UTC ... INFORMATION
-------------------------------
LOCATION...16.9N 59.1W
ABOUT 180 MI ... 290 KM E OF ANTIGUA
ABOUT 185 MI ... 295 KM ESE OF BARBUDA
MAXIMUM SUSTAINED WINDS...185 MPH...295 KM/H
PRESENT MOVEMENT ... W OR 275 DEGREES AT 14 MPH ... 22 KM/H
MINIMUM CENTRAL PRESSURE ... 926 MB ... 27.34 INCHES

Irma is now the second strongest hurricane in terms of maximum sustained winds in the Atlantic basin -- and the strongest as such outside of the Caribbean Sea or Gulf of Mexico.

All 17 Atlantic basin hurricanes with top sustained winds of at least 175MPH organized by minimum pressure.

In the case of Irma, you can increase the maximum sustained winds now to 185mph and decrease its central pressure to 926mb.

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As others have noted, this hurricane presently resembles one of those super-typhoons of the western tropical Pacific. Conditions in the Atlantic basin just aren't usually this favorable for a tropical cyclone of this magnitude.


Were this to hit Miami directly, it would destroy the city in a trillion dollar mega-disaster.

The operational GFS 12Z Sept. 4, 2017 run showing 6-hour averaged precipitation rate (in mm/hr), mean sea level pressure (in hPa), and 1000-500mb thicknesses (in dam) valid at hour 150 18Z Sept. 10, 2017 for the southeastern U.S., as prettied up by the Tropical Tidbits site.

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On a personal note, my father down there in Flagler Beach refused to evacuate from his beachside trailer during Hurricane Matthew last year. Irma is a completely different category of beast.

GOES floater IR view of Hurricane Irma, 1645UTC (12:45PM EDT) September 5, 2017.

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Below are the 12Z Sept. 5, 2017 GFS (GEFS) and European (EPS) ensembles track forecast for Irma. Both ensemble systems indicate a sharp right turn to the north on Saturday in response to shortwave dropping over the eastern United States and a concomitant weakening in the western flank of a sprawling ridge over the Atlantic Ocean that is presently keeping the storm on a westerly motion.

12Z Sept. 5, 2017 Euro ensembles track forecast of Hurricane Irma through hour 216.

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12Z Sept. 5, 2017 GEFS track forecast of Hurricane Irma through hour 216.

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I'll have a lot more to say about Irma in upcoming entries. In the meantime, the Capital Weather Gang is very much on top of this developing situation.

--Regulus

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