Monday, September 18, 2017

Notes on Hurricane Irma

Hurricane Irma on September 8.
Five days ago the last remnants of what was once Hurricane Irma fizzled over the eastern U.S. Attention is now focused on dangerous Hurricane Maria, which at this writing is slamming the island of Dominca. For the most up to date information on Maria, Jose, and Lee visit the National Hurricane Center web site.

As Hurricane Irma gained strength I and many others were riveted to web sites, social media, and news programs tracking the progress of the storm. In this day of nearly instant communication of information it's not hard to get immersed in following the progress of a storm like this. Periodically I grabbed images and information to save in anticipation of a blog post or two about this storm. Irma and its aftermath has been well-documented so I won't rehash Irma's history here. What I would like to do is share some of the images and information I collected during the storm that you may not have seen.

The first land Irma slammed into was the island of Barbuda. Barbuda is one of two major islands that make up the Caribbean nation of Antigua and Barbuda in the middle of the Leeward Islands. Irma made a direct hit on Barbuda.

Here is the radar image from Guadalupe showing the eyewall of Irma over Barbuda at 0100 local time. Winds were likely gusting to 170 mph or more over the island.


Here is the series of weather observations from Barbuda for the two hours prior to the arrival of the eye.  Sustained hurricane force winds with gusts as high as 155 mph were recorded at this station on the southwest side of the island. Note that the CALM winds reported for the last two observations were not from being in the eye, but were due to the destruction of the anemometer.


Weather observations from Barbuda as Irma made landfall September 6.

This radar image at 1:30 a.m. local time shows the entire island of Barbuda in the calm eye of the hurricane.

Irma left widespread destruction across Barbuda. The island was evacuated after the hurricane moved on, leaving the island uninhabited for the first time in 300 years.

Irma's path then took it through the Virgin islands, producing destruction across St. Thomas, St. John, and St. Maarten.

Damage in St. Maarten.
Photo: Dutch Defense Ministry

Irma continued WNW and passed to the north of the Dominican Republic and Puerto Rico.

Hurricane Irma approaches Puerto Rico on September 6.

Irma was able to maintain its strength due to the very warm water in the southern Atlantic and Caribbean, especially the area between Cuba and the Bahamas. Sea surface temperatures in this region were in the range of 85°F to 90°F

Sea surface temperatures on September 6.


One interesting image is this one of all the marine traffic around Florida on Saturday, September 8, heading south and east. It's interesting to note the number of cruise ships.

Marine traffic near Florida on the morning of September 8.


After brushing along the north coast of Cuba on Saturday, September 9, Irma turned north toward the Florida Keys. The eye of the storm made landfall in the Florida Keys, east of Key West, around 8:00 a.m EDT, Sunday, September 9.

Radar image from the NWS Key West radar at 8:02 a.m. EDT September 10.


After crossing the keys, the eye of Irma was over open water and headed to another landfall on the Florida west coast. Irma made its final landfall near Marco Island, FL at 3:35 p.m. EDT on Sunday.

Radar image from the NWS Key West radar at 3:35 p.m. EDT September 10.


Hurricane Irma was certainly a storm of record. No doubt the name Irma will be retired. Philip Klotzbach, a tropical storm researcher at Colorado State University, compiled a list of of records and notable facts about Irma.
 
Josh Morgerman (iCyclone on Facebook and Twitter), a professional hurricane chaser, was in Naples, FL when Irma made landfall. He produced a video of his experience which you can view here.



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