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Irma Now Category 5, Winds near 185 mph

5 Sep 2017, 10:25 am

Hurricane Irma has continued to strengthen and this morning reached a powerful category 5 status, with 185 mph sustained winds and gusts to 220 mph. This makes Irma the strongest storm ever recorded in the Atlantic Basin, outside of the Caribbean Sea and Gulf of Mexico.  Irma is now in the top 5 for strongest hurricanes observed.

Irma is moving to the west at 14 mph. Satellite and radar images show an impressive and dangerous storm, with a 25 to 30 mile wide eye. The eye of Irma storm is located about 225 miles east of Antigua and about 230 miles east-southeast of Barbuda. Residents in the Leeward Islands should complete their preparations very soon as the weather will begin to deteriorate over the easternmost Leeward Islands later this afternoon.

A Hurricane Warning is in effect for…
* Antigua, Barbuda, Anguilla, Montserrat, St. Kitts, and Nevis
* Saba, St. Eustatius, and Sint Maarten
* Saint Martin and Saint Barthelemy
* British Virgin Islands
* U.S. Virgin Islands
* Puerto Rico, Vieques, and Culebra

A Hurricane Watch is in effect for…
* Guadeloupe
* Dominican Republic from Cabo Engano to the northern border with
* Haiti from the northern border with the Dominican Republic to Le
Mole St. Nicholas
* Turks and Caicos Islands
* Southeastern Bahamas

A Tropical Storm Warning is in effect for…
* Guadeloupe
* Dominica

A Tropical Storm Watch is in effect for…
* Dominican Republic from south of Cabo Engao to Isla Saona
* Haiti from south of Le Mole St. Nicholas to Port-Au-Prince

Interests elsewhere in the Dominican Republic and Haiti, as well as Cuba, the central and northwestern Bahamas, and Florida should monitor the progress of Irma, with watches possible in the near future.

Irma is expected to maintain major hurricane status into this weekend.  Conditions are favorable around the storm: wind shear remains low, mid-level atmosphere is moist, water temperatures are very warm. These conditions should allow the hurricane to remain very intense throughout much of the forecast period, however, fluctuations in intensity are likely to occur as eyewall replacement cycles take place. The path assumes little overall interaction of Irma with the islands of the Greater Antilles.

A strong subtropical ridge, the Bermuda High centered over the Central Atlantic, should steer Irma generally westward. The ridge is expected to remain in place over the western Atlantic during the next several days and Irma is forecast to move west-northwestward throughout the most of remainder of the forecast period. This weekend, an upper level trough dropping southward over the central United States is expected to begin eroding the western portion of the ridge, allowing a Irma to move northward.

The National Hurricane Center reminds everyone that since Irma is a large hurricane, don’t focus on the exact forecast track since tropical storm- and hurricane-force winds and life-threatening storm surge extend far from the center.

Looking back in history, Hurricane Donna in 1960 was a storm with an similar path (current and forecast).  According to the National Hurricane Center, Donna was first detected as a tropical wave moving off the African coast on August 29. It became a tropical storm over the tropical Atlantic the next day and a hurricane on September 1. Donna followed a general west-northwestward track for the following five days, passing over the northern Leeward Islands, north of Puerto Rico, and into the southeastern Bahamas. A sharp northwestward turn on September 9th brought the hurricane to the middle Florida Keys as a Category 4 storm. Donna then curved northeastward, crossing the Florida Peninsula on September 11, followed by eastern North Carolina (Category 3) on the 12th, and the New England states (Category 3 on Long Island and Categories 1 to 2 elsewhere) into the 13th.

Donna is the only hurricane of record to produce hurricane-force winds in Florida, the Mid-Atlantic states, and New England. Sombrero Key, Florida reported 128 mph sustained winds with gusts to 150 mph. In the Mid-Atlantic states, Elizabeth City, North Carolina reported 83 mph sustained winds, while Manteo, North Carolina reported a 120 mph gust. In New England, Block Island, Rhode Island reported 95 mph sustained winds with gusts to 130 mph.

Donna caused storm surges of up to 13 ft in the Florida Keys and 11 ft surges along the southwest coast of Florida. Four to eight ft surges were reported along portions of the North Carolina coast, with 5 to 10 ft surges along portions of the New England coast. Heavy rainfalls of 10 to 15 inches occurred in Puerto Rico, 6 to 12 inches in Florida, and 4 to 8 inches elsewhere along the path of the hurricane.

The landfall pressure of 27.46 inches makes Donna the fifth strongest hurricane of record to hit the United States. It was responsible for 50 deaths in the United States. One hundred and fourteen deaths were reported from the Leeward Islands to the Bahamas, including 107 in Puerto Rico caused by flooding from the heavy rains. The hurricane caused $387 million in damage in the United States and $13 million elsewhere along its path.


For WeatherNation: Meteorologist Mace Michaels

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