Hurricane Irma Advisory Number 29
NWS National Hurricane Center Miami FL AL112017
500 AM AST Wed Sep 06 2017
...EYE OF POTENTIALLY CATASTROPHIC CATEGORY 5 HURRICANE IRMA
MOVING AWAY FROM BARBUDA AND TOWARD ST. MARTIN...
SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
ABOUT 35 MI...55 KM ESE OF ST. MARTIN
ABOUT 145 MI...235 KM E OF ST. CROIX
MAXIMUM SUSTAINED WINDS...185 MPH...295 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...914 MB...26.99 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The Government of the Bahamas has issued a Hurricane Warning for
the Southeastern Bahamas and the Turks and Caicos Islands, and a
Hurricane Watch for the Central Bahamas.
The Meteorological Service of Barbados has discontinued the
Tropical Storm Warning for Dominica.
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
* Dominican Republic from Cabo Engano to the northern border with
* Southeastern Bahamas and the Turks and Caicos Islands
A Hurricane Watch is in effect for...
* Haiti from the northern border with the Dominican Republic to Le
Mole St. Nicholas
* Turks and Caicos Islands
* Southeastern Bahamas
* Cuba from Matanzas province eastward to Guantanamo province
* Central Bahamas
A Tropical Storm Warning is in effect for...
* Dominican Republic from south of Cabo Engano westward to the
southern border with Haiti
A Tropical Storm Watch is in effect for...
* Haiti from south of Le Mole St. Nicholas to Port-Au-Prince
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.
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 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
DISCUSSION AND 48-HOUR OUTLOOK
At 500 AM AST (0900 UTC), the center of Hurricane Irma was located
near latitude 17.9 North, longitude 62.6 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 move over
portions of the northern Leeward Islands this morning, move near or
over portions of the northern Virgin Islands later today, and pass
near or just north of Puerto Rico this afternoon or tonight.
Maximum sustained winds remain 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 175 miles
(280 km). St. Martin recently reported a wind gust of 61 mph
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.
Northern Leeward Islands...7 to 11 ft
Turks and Caicos Islands...15 to 20 ft
Southeastern 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
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...3 to 5 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 occuring within the hurricane
warning area in the Leeward Islands and should continue through
today. Hurricane conditions are expected to begin within the
hurricane warning area in the British and U.S. Virgin Islands and
Puerto Rico later today and tonight, with tropical storm conditions
beginning this morning. Hurricane conditions are expected to begin
within the hurricane warning area in the Dominican Republic early
Thursday, with tropical storm conditions beginning tonight.
Hurricane conditions are expected in the warning area in the
southeastern Bahamas and the Turks and Caicos Islands beginning
Hurricane and tropical storm conditions are possible within the
watch area in Haiti by early Thursday and in the central Bahamas by
RAINFALL: Irma is expected to produce the following rain
accumulations through Thursday:
Northern Leeward Islands...8 to 12 inches, isolated 20 inches
Northeast Puerto Rico and the British and U.S. Virgin Islands...4 to
10 inches, isolated 15 inches Southwest Puerto Rico, the southern
Leeward Islands, and Saint Croix...2 to 4 inches
Irma is expected to produce the following rain accumulations
Wednesday through Saturday:
Southeast Bahamas, the Turks and Caicos and eastern to central
Cuba...8 to 12 inches, isolated 20 inches
Northern Dominican Republic and northern Haiti...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 intermediate advisory at 800 AM AST.
Next complete advisory at 1100 AM AST.