NWS National Hurricane Center Miami FL AL112017
800 AM AST Tue Sep 05 2017
…IRMA BECOMES AN EXTREMELY DANGEROUS CATEGORY 5 HURRICANE…
…PREPARATIONS SHOULD BE RUSHED TO COMPLETION IN THE HURRICANE
SUMMARY OF 800 AM AST…1200 UTC…INFORMATION
ABOUT 270 MI…440 KM E OF ANTIGUA
ABOUT 280 MI…445 KM ESE OF BARBUDA
MAXIMUM SUSTAINED WINDS…175 MPH…280 KM/H
PRESENT MOVEMENT…W OR 280 DEGREES AT 14 MPH…22 KM/H
MINIMUM CENTRAL PRESSURE…929 MB…27.44 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The government of the Dominican Republic has issued a Hurricane Watch from Cabo Engano to the northern border with Haiti and a Tropical Storm Watch from south of Cabo Engao to Isla Saona.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
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…
* Dominican Republic from Cabo Engano to the northern border with Haiti
A Tropical Storm Warning is in effect for…
A Tropical Storm Watch is in effect for…
* Dominican Republic from south of Cabo Engao to Isla Saona
A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. A warning is typically issued 36 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. In this case, for some of easternmost islands, the hurricane conditions are expected within the next 24 hours.
Preparations to protect life and property should be rushed to completion.
A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area in this case within 36 hours.
A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours.
Interests elsewhere in the Dominican Republic, along with Haiti, the Turks and Caicos Islands, Cuba, and the southeastern and central Bahamas should monitor the progress of Irma.
For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. For storm information specific to your area outside the United States, please monitor products issued by your national meteorological service.
DISCUSSION AND 48-HOUR OUTLOOK
At 800 AM AST (1200 UTC), the distinct eye center of Hurricane Irma was located near latitude 16.7 North, longitude 57.7 West. Irma is moving toward the west near 14 mph (22 km/h), and this general motion is expected to continue today, followed by a turn toward the west-northwest tonight. On the forecast track, the dangerous core of Irma will move near or over portions of the northern Leeward Islands tonight and early Wednesday.
Reports from NOAA and U.S. Air Force Hurricane Hunter aircraft indicate Irma continues to strengthen and maximum sustained winds have increased to near 175 mph (280 km/h) with higher gusts. Irma is an extremely dangerous category 5 hurricane on the Saffir-Simpson Hurricane Wind Scale. Some fluctuations in intensity are likely during the next day or two, but Irma is forecast to remain a powerful category 4 or 5 hurricane during the next couple of days.
Hurricane-force winds extend outward up to 45 miles (75 km) from the center and tropical-storm-force winds extend outward up to 140 miles (220 km).
The latest estimated minimum central pressure from aircraft data is 929 mb (27.44 inches).
HAZARDS AFFECTING LAND
STORM SURGE: The combination of a dangerous storm surge and large breaking waves will raise water levels by as much as 7 to 11 feet above normal tide levels along the coasts of the extreme northern Leeward Islands within the hurricane warning area near and to the north of the center of Irma. Near the coast, the surge will be accompanied by large and destructive waves.
The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water is expected to reach the following heights above ground if the peak surge occurs at the time of high tide…
British and U.S. Virgin Islands except St. Croix…7 to 11 ft
Northern coast of Puerto Rico…2 to 4 ft
Southern coast of Puerto Rico and St. Croix…1 to 2 ft
The deepest water will occur along the immediate coast in areas of onshore winds, where the surge will be accompanied by large and destructive waves. Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office.
WIND: Hurricane conditions are expected within the hurricane warning area in the Leeward Islands by tonight, with tropical storm conditions beginning later today. Tropical storm conditions are expected within the tropical storm warning area where hurricane conditions are also possible. Hurricane conditions are expected to begin within the hurricane warning area in the British and U.S. Virgin Islands and Puerto Rico on Wednesday, with tropical storm conditions beginning tonight. Hurricane and tropical storm conditions are possible within the watch area in the Dominican Republic by early Thursday.
RAINFALL: Irma is expected to produce total rainfall accumulations of 4 to 8 inches with isolated maximum amounts of 12 inches across the northern Leeward Islands, the British and U.S. Virgin Islands, and Puerto Rico. These rainfall amounts may cause life-threatening flash floods and mudslides.
SURF: Swells generated by Irma will affect the northern Leeward Islands, Puerto Rico, and the U.S. and British Virgin Islands during the next several days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office.
Source: The Daily Herald https://www.thedailyherald.sx/islands/69216-hurricane-irma-special-advisory-number-25