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Tropical Storm Isaac Advisory Number 19
NWS National Hurricane Center Miami FL AL092018
500 AM AST Wed Sep 12 2018
...ISAAC A LITTLE WEAKER AS IT MOVES TOWARD THE LESSER ANTILLES...
SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
ABOUT 500 MI...805 KM E OF MARTINIQUE
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Tropical Storm Warning is in effect for...
A Tropical Storm Watch is in effect for...
* St. Kitts and Nevis
* Saba and St. Eustatius
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, in this case within 36 to 48 hours.
Interests elsewhere in the Leeward Islands should monitor the
progress of Isaac.
For storm information specific to your area, please monitor
products issued by your national meteorological service.
DISCUSSION AND OUTLOOK
At 500 AM AST (0900 UTC), the center of Tropical Storm Isaac was
located near latitude 14.5 North, longitude 53.5 West. Isaac is
moving toward the west near 16 mph (26 km/h) and this general
motion is expected to continue through the weekend. On the forecast
track, Isaac's center is forecast to move across the central Lesser
Antilles and into the eastern Caribbean Sea on Thursday.
Maximum sustained winds have decreased to near 60 mph (95 km/h) with
higher gusts. Gradual weakening is forecast during the next few
Tropical-storm-force winds extend outward up to 105 miles (165 km)
from the center.
The estimated minimum central pressure is 1000 mb (29.53 inches).
A NOAA hurricane hunter aircraft is scheduled to investigate
Isaac later this morning and should provide a better assessment of
the intensity of the tropical storm and the extent of its winds.
HAZARDS AFFECTING LAND
RAINFALL: Isaac is expected to produce total rainfall accumulations
of 2 to 4 inches with isolated amounts up to 8 inches across
Martinique, Dominica, and Guadeloupe, with up to one inch
anticipated across the remaining Windward and Leeward Islands.
WIND: Tropical storm conditions are expected on Martinique,
Dominica, and Guadeloupe by tonight or early Thursday. Tropical
storm conditions are possible within the tropical storm watch area
STORM SURGE: Some coastal flooding is possible in areas of onshore
winds. Near the coast, the surge will be accompanied by large
SURF: Swells generated by Isaac will begin to affect portions
of the Lesser Antilles this afternoon. 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.