On the morning of Sunday, September 10, 2017 Hurricane IRMA made landfall in the lower Florida Keys as a category four on the Saffir-Simpson Hurricane Wind Scale. The center of the storm crossed Cudjoe Key with maximum sustained winds of 130 mph (115 kt) and a minimum central pressure of 931 mb (27.49 in). After passing the Florida Keys, IRMA made a second landfall in southwest Florida, over Marco Island and Naples, as a category three, with sustained winds of 115 mph (100 kt) and a minimum central pressure of 936 mb (27.64 in).
From September 9th - 10th, storm chasers Michael Laca, Greg Nordstrom, Devin Thomas, Dylan Federico, and Brant Beckman intercepted Hurricane IRMA in Naples, Florida (26.14207 N / 81.79721 W)
Between 3:45 pm and 4:35 pm EDT our location was directly impacted by the hurricane's intense northern eyewall, which was characterized by exceptionally turbulent bursts of violent winds. While the highest normalized surface winds, in our immediate vicinity, were sustained (1 min) around 100 mph (85 kt), peak (3 sec) gusts were likely in the 130-140 mph (115-120 kt) range, coming in frequent, explosive bursts which engulfed everything in blinding whiteouts of wind and rain. A peak gust of 142 mph (123 kt) was reported from a MESONET site at the Naples Municipal Airport, 1.5 miles east of our location, and a gust to 130 mph (115 kt) was reported at the Marco Island Police Department. Post-storm damage surveys have indicated that IRMA's eyewall was likely producing a number of transient mesovortex features, which may have resulted in some of the more extreme wind values, and exceptional turbulence observed.
My location experienced a 40 minute calm (from 4:40 pm to 5:20 pm EDT) during the passage of the hurricane's eye. At 4:53 pm EDT, shortly after the onset of the calm conditions, I recorded a minimum pressure of 938.7 mb (27.72 in). A minimum pressure of 936.9 mb (27.67 in) was reported from a storm spotter on Marco Island.