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Hurricane Irma Intermediate Advisory Number 31A
NWS National Hurricane Center Miami FL AL112017
800 PM AST Wed Sep 06 2017
...EYE OF CATEGORY 5 HURRICANE IRMA PASSING JUST NORTH OF
SUMMARY OF 800 PM AST...0000 UTC...INFORMATION
ABOUT 50 MI...80 KM N OF SAN JUAN PUERTO RICO
MAXIMUM SUSTAINED WINDS...185 MPH...295 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...914 MB...26.99 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Hurricane Warning is in effect for...
* British Virgin Islands
* U.S. Virgin Islands
* Puerto Rico, Vieques, and Culebra
* Dominican Republic from Cabo Engano to the northern border with
* Haiti from the northern border with the Dominican Republic to Le
Mole St. Nicholas
* Southeastern Bahamas and the Turks and Caicos Islands
* Central Bahamas
A Hurricane Watch is in effect for...
* Cuba from Matanzas province eastward to Guantanamo province
* Northwestern Bahamas
A Tropical Storm Warning is in effect for...
* Dominican Republic from south of Cabo Engano westward to the
southern border with Haiti
* Haiti from south of Le Mole St. Nicholas to Port-Au-Prince
* Cuba provinces of Guantanamo, Holguin, and Las Tunas
A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area. 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
A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area.
Interests elsewhere in the Dominican Republic and Haiti, as well as
Cuba, the northwestern Bahamas, and Florida 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 PM AST (0000 UTC), the eye of Hurricane Irma was located near
latitude 19.1 North, longitude 66.1 West. Irma is moving toward the
west-northwest near 16 mph (26 km/h), and this general motion is
expected to continue for the next couple of days. On the forecast
track, the extremely dangerous core of Irma will continue to pass
just north of Puerto Rico tonight, pass near or just north of the
coast of Hispaniola Thursday, and be near the Turks and Caicos and
southeastern Bahamas by Thursday evening.
Maximum sustained winds are near 185 mph (295 km/h) with higher
gusts. Irma is a 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 50 miles (85 km) from
the center and tropical-storm-force winds extend outward up to 185
miles (295 km). A sustained wind of 55 mph (89 km/h) with a gust
to 70 mph (113 km/h) was recently reported at an NOS observing
site in San Juan Bay, Puerto Rico.
The estimated minimum central pressure is 914 mb (26.99 inches).
HAZARDS AFFECTING LAND
STORM SURGE: The combination of a life-threatening storm surge and
large breaking waves will raise water levels ABOVE NORMAL TIDE
LEVELS by the following amounts 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.
Turks and Caicos Islands...15 to 20 ft
Southeastern and central Bahamas...15 to 20 ft
Northern coast of the Dominican Republic...3 to 5 ft
Northern coast of Haiti and the Gulf of Gonave...1 to 3 ft
Northern coast of Cuba in the warning area...5 to 10 ft
Water levels in the Leeward Islands will gradually subside tonight.
The combination of a life-threatening 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...4 to 6 ft
Southern coast of Puerto Rico and St. Croix...2 to 4 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: Tropical Storm and Hurricane conditions will continue to
spread westward over portions of Puerto Rico tonight. Hurricane
conditions are expected to begin within the hurricane warning area
in the Dominican Republic and Haiti early Thursday, with tropical
storm conditions beginning tonight. Hurricane conditions are
expected to begin in the warning area in the southeastern Bahamas
and the Turks and Caicos Islands on Thursday with tropical storm
conditions by late tonight. These conditions will spread into the
Central Bahamas by Thursday night.
Hurricane and tropical storm conditions are possible within the
watch area in the central Bahamas and Cuba by Friday. Tropical
storm conditions are expected to begin within the warning area in
Cuba Thursday night.
RAINFALL: Irma is expected to produce the following rain
accumulations through Saturday:
Northern Leeward Islands...Additional 1 to 3 inches. Storm total 8
to 12 inches, isolated 20 inches.
Northeast Puerto Rico and the British and U.S. Virgin Islands...6 to
12 inches, isolated 20 inches.
Southwest Puerto Rico...3 to 6 inches, isolated 10 inches.
The Southern Leeward Islands, and Saint Croix...2 to 4 inches.
Southeast Bahamas, Central Bahamas, and the Turks and Caicos...8 to
12 inches, isolated 20 inches.
Northern Dominican Republic and northern Haiti...4 to 10 inches,
isolated 15 inches.
Eastern and Central Cuba...4 to 10 inches, isolated 15 inches.
Southwest Haiti...1 to 4 inches.
In all areas this rainfall may cause life-threatening flash floods
SURF: Swells generated by Irma will affect the northern Leeward
Islands, Puerto Rico, the Virgin Islands, the southeastern Bahamas,
the Turks and Caicos Islands, the northern coast of the Dominican
Republic, and portions of the southeast coast of the United States
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 1100 PM AST.