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BULLETIN
Tropical Storm Isaac Advisory Number  23
NWS National Hurricane Center Miami FL       AL092018
500 AM AST Thu Sep 13 2018

...TROPICAL-STORM-FORCE WINDS NEARING THE LEEWARD ISLANDS...
...GUSTY CONDITIONS EXPECTED THROUGHOUT THE DAY...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...15.4N 59.7W
ABOUT 105 MI...170 KM E OF DOMINICA
ABOUT 130 MI...205 KM ESE OF GUADELOUPE
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 17 MPH...28 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The government of Antigua has issued a Tropical Storm Watch for
Barbuda.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Martinique
* Dominica
* Guadeloupe

A Tropical Storm Watch is in effect for...
* Antigua
* Barbuda
* Montserrat
* St. Kitts and Nevis
* Saba and St. Eustatius
* St. Martin and St. Maarten

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area, in this case within the
next few hours.

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, in this case within the next few
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 15.4 North, longitude 59.7 West. Isaac is
moving toward the west near 17 mph (28 km/h).  This general motion
is forecast to continue for the next several days.  On the forecast
track, Isaac is forecast to move across the central Lesser Antilles
and into the eastern Caribbean Sea later today, and then move across
the eastern and central Caribbean Sea through the weekend.

Earlier data from a NOAA Hurricane Hunter aircraft indicate that
maximum sustained winds are near 45 mph (75 km/h) with higher gusts.
Little change in strength is expected over the next several hours as
Isaac moves through the Leeward Islands.  Gradual weakening is
forecast after that as Isaac moves through the eastern Caribbean.

Tropical-storm-force winds extend outward up to 160 miles (260 km)
from the center.

The estimated minimum central pressure is 1006 mb (29.71 inches).


HAZARDS AFFECTING LAND
----------------------
RAINFALL:  Tropical Storm Isaac is expected to produce total
rainfall accumulations of 2 to 4 inches with isolated amounts up to
6 inches across Martinique, Dominica, and Guadeloupe, especially
over elevated terrain.  Rainfall of 0.5 to 1.5 inches with isolated
amounts to 3 inches are forecast across Puerto Rico and the southern
United States Virgin Islands, with up to an inch anticipated across
the remaining Windward and Leeward Islands.  This rainfall may cause
dangerous flash flooding.

WIND:  Tropical storm conditions are expected within the tropical
storm warning area beginning within the next few hours through the
afternoon. Tropical storm conditions are possible within the
tropical storm watch area, also beginning later this morning.

STORM SURGE:  Some coastal flooding is possible in areas of onshore
winds.  Near the coast, the surge will be accompanied by large
waves.

SURF:  Swells generated by Isaac are affecting portions of the
Lesser Antilles.  These swells are likely to cause life-threatening
surf and rip current conditions.  Please consult products from your
local weather office.


NEXT ADVISORY
-------------
Next intermediate advisory at 800 AM AST.
Next complete advisory at 1100 AM AST.

$$
Forecaster Zelinsky

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