Meteorological Department St. Maarten : IRMA Special report 3
Hurricane Irma Intermediate Advisory Number 20A
NWS National Hurricane Center Miami FL AL112017
800 AM AST Mon Sep 04 2017
…NOAA HURRICANE HUNTER AIRCRAFT FINDS IRMA A LITTLE STRONGER…
SUMMARY OF 800 AM AST…1200 UTC…INFORMATION
ABOUT 610 MI…980 KM E OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS…120 MPH…195 KM/H
PRESENT MOVEMENT…WSW OR 255 DEGREES AT 14 MPH…22 KM/H
MINIMUM CENTRAL PRESSURE…947 MB…27.96 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Hurricane Watch is in effect for…
* Antigua, Barbuda, Anguilla, Montserrat, St. Kitts, and Nevis
* Saba, St. Eustatius, and Sint Maarten
* Saint Martin and Saint Barthelemy
A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous.
Interests in the remainder of the Leeward Islands, the British and U.S. Virgin Islands, Puerto Rico, and the Dominican Republic should monitor the progress of Irma. Additional hurricane and tropical storm watches and warnings will likely be required for portions of this area later this morning or this afternoon.
For storm information specific to your area, please monitor products issued by your national meteorological service.
DISCUSSION AND 48-HOUR OUTLOOK
At 800 AM AST (1200 UTC), the eye of Hurricane Irma was located near latitude 16.8 North, longitude 52.6 West. Irma is moving toward the west-southwest near 14 mph (22 km/h). A turn toward the west is expected later today, followed by a west-northwestward turn late Tuesday. On the forecast track, the center of Irma will move closer to the Leeward Islands through Tuesday and then be near the northern Leeward Islands Tuesday night.
Data from a NOAA Hurricane Hunter aircraft indicate that the maximum sustained winds have increased to near 120 mph (195 km/h) with higher gusts. Irma is a category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale. Additional strengthening is forecast through Tuesday night.
Hurricane-force winds extend outward up to 30 miles (45 km) from the center, and tropical-storm-force winds extend outward up to 140 miles (220 km).
The latest minimum central pressure estimated from data received by the reconnaissance aircraft is 947 mb (27.96 inches).
HAZARDS AFFECTING LAND
WIND: Hurricane conditions are possible within the watch area by Tuesday night, with tropical storm conditions possible by late Tuesday.
SURF: Swells generated by Irma will begin affecting the northern Leeward Islands today. 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/69184-hurricane-irma-intermediate-advisory-number-20a