Hurricane Irma Intermediate Advisory Number 23A…Corrected
NWS National Hurricane Center Miami FL AL112017
200 AM AST Tue Sep 05 2017
Corrected for Rushed instead of Rush in the headline
…SEVERE HURRICANE IRMA POSES A SERIOUS THREAT TO THE LEEWARD
…ALL PREPARATIONS SHOULD BE RUSHED TO COMPLETION…
SUMMARY OF 200 AM AST…0600 UTC…INFORMATION
ABOUT 360 MI…575 KM E OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS…145 MPH…235 KM/H
PRESENT MOVEMENT…W OR 270 DEGREES AT 13 MPH…20 KM/H
MINIMUM CENTRAL PRESSURE…939 MB…27.73 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
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…
A Tropical Storm Warning is in effect for…
A Tropical Storm Watch is in effect for…
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. Preparations to protect life and property should be
rushed to completion.
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.
A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within 36 hours.
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.
Interests in the Dominican Republic, 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
DISCUSSION AND 48-HOUR OUTLOOK
At 200 AM AST (0600 UTC), the eye of Hurricane Irma was located by
an Air Force Hurricane Hunter aircraft near latitude 16.6 North,
longitude 56.4 West. Irma is moving toward the west near 13 mph (20
km/h), and this general motion is expected to continue today,
followed by a turn toward the west-northwest Tuesday night. On the
forecast track, the center of Irma will move near or over portions
of the northern Leeward Islands Tuesday night and early Wednesday.
Data from an Air Force Hurricane Hunter plane indicate that the
maximum sustained winds have increased to near 145 mph (235 km/h)
with higher gusts. Irma is a category 4 hurricane on the
Saffir-Simpson Hurricane Wind Scale. Additional strengthening is
possible during the next 48 hours.
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 minimum central pressure just estimated from a Hurricane Hunter
plane was 939 mb (27.73 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 6 to 9 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…4 to 6 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
WIND: Hurricane conditions are expected within the hurricane
warning area by Tuesday night, with tropical storm conditions
beginning earlier during the day. Tropical storm conditions are
expected within the tropical storm warning area where hurricane
conditions are also possible.
RAINFALL: Irma is expected to produce total rainfall accumulations
of 3 to 6 inches with isolated maximum amounts of 10 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.
Next complete advisory at 500 AM AST.