Hurricane Irma Advisory Number 26
NWS National Hurricane Center Miami FL AL112017
1100 AM AST Tue Sep 05 2017
…POTENTIALLY CATASTROPHIC CATEGORY 5 HURRICANE IRMA HEADING
TOWARD THE LEEWARD ISLANDS…
…PREPARATIONS SHOULD BE RUSHED TO COMPLETION IN THE HURRICANE
SUMMARY OF 1100 AM AST…1500 UTC…INFORMATION
ABOUT 225 MI…365 KM E OF ANTIGUA
ABOUT 230 MI…370 KM ESE OF BARBUDA
MAXIMUM SUSTAINED WINDS…180 MPH…285 KM/H
PRESENT MOVEMENT…W OR 270 DEGREES AT 14 MPH…22 KM/H
MINIMUM CENTRAL PRESSURE…931 MB…27.50 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The government of the Bahamas has issued a Hurricane Watch for the
Turks and Caicos Islands and the southeastern Bahamas, including the
Acklins, Crooked Island, Long Cay, the Inaguas, Mayaguana, and the
A Hurricane Watch has been issued for the north coast of Haiti from
the border of the Dominican Republic westward to Le Mole St.
Nicholas. A Tropical Storm Watch has been issued from south of Le
Mole St. Nicholas to Port-Au-Prince.
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 from the northern border with the Dominican Republic to Le
Mole St. Nicholas
* Turks and Caicos Islands
* Southeastern Bahamas
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
* 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. 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 12 to 24 hours.
Preparations to protect life and property should be rushed to
A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area in this case within 36
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 central and 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 1100 AM AST (1500 UTC), the eye of Hurricane Irma was located
near latitude 16.8 North, longitude 58.4 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 extremely dangerous core of Irma
is forecast to move over portions of the northern Leeward Islands
tonight and early Wednesday.
Reports from an Air Force Hurricane Hunter aircraft indicate that
the maximum sustained winds are near 180 mph (285 km/h) with higher
gusts. Irma is a 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
Hurricane-force winds extend outward up to 60 miles (95 km) from the
center and tropical-storm-force winds extend outward up to 160 miles
The latest minimum central pressure reported by reconnaissance
aircraft is 931 mb (27.50 inches).
HAZARDS AFFECTING LAND
STORM SURGE: The combination of a life-threatening 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 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 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, Haiti, the Turks and Caicos,
and the southeastern Bahamas by early Thursday.
RAINFALL: Irma is expected to produce total rain accumulations
of 8 to 12 inches with isolated maximum amounts of 18 inches across
the northern Leeward Islands. Irma is expected to produce total
rain accumulations of 4 to 10 inches with isolated maximum amounts
of 15 inches across northeast Puerto Rico and the British and U.S.
Virgin Islands, and amounts of 2 to 4 inches over southwest Puerto
Rico, the southern Leeward Islands, and Saint Croix. This rainfall
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 intermediate advisory at 200 PM AST.
Next complete advisory at 500 PM AST.