Sep 5, 2017

Extremely Dangerous Cat 5 Irma Storms into Leeward Islands

Antigua and Barbuda
by
Bob Henson
,
Category 6 | Weather Underground
MODIS image of Hurricane Irma taken on Tuesday afternoon, September 5, 2017. At the time, Irma was a Category 5 storm with 185 mph winds. Image: NASA
MODIS image of Hurricane Irma taken on Tuesday afternoon, September 5, 2017. At the time, Irma was a Category 5 storm with 185 mph winds. Image: NASA

As noted above, Irma’s peak sustained surface winds of 185 mph are the highest observed in any hurricane north of the Caribbean and east of Florida, topped only by Allen (1980) in the Caribbean (190 mph). Two hurricanes have notched 185-mph winds in the Caribbean: Gilbert (1988) and Wilma (2005). The Labor Day hurricane of 1935 hit the same peak winds in the Florida Straits.

Irma set another record late Tuesday afternoon: its central surface pressure dropped to 916 mb, as extrapolated from dropsonde data collected by Hurricane Hunters. This beats the previous Atlantic record outside of the Caribbean and Gulf of Mexico, a 919 mb reading from a dropsonde with Hurricane Gloria (1985).

Irma's central pressure at 2 pm EDT Tuesday, when the hurricane's top winds first hit 185 mph, was 926 mb. Interestingly, the other four Atlantic hurricanes with winds at least that strong had significantly lower central pressures:

Wilma:  882 mb
Gilbert:  888 mb
Labor Day 1935:  892 mb
Allen:  899 mb