ZCZC MIATCPAT4 ALL
TTAA00 KNHC DDHHMM
Tropical Storm Isaac Intermediate Advisory Number 23A
NWS National Hurricane Center Miami FL AL092018
800 AM AST Thu Sep 13 2018
...TROPICAL-STORM-FORCE WINDS EXPECTED SOON IN THE LEEWARD
SUMMARY OF 800 AM AST...1200 UTC...INFORMATION
ABOUT 25 MI...40 KM E OF DOMINICA
ABOUT 80 MI...130 KM SSE OF GUADELOUPE
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 21 MPH...33 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 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
* 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
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 800 AM AST (1200 UTC), the center of Tropical Storm Isaac was
located near latitude 15.2 North, longitude 60.9 West. Isaac is
moving faster toward the west near 21 mph (33 km/h). This general
motion is forecast to continue today with a decrease in forward
speed over the Caribbean Sea. On the forecast track, Isaac should
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.
Maximum sustained winds remain 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
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 complete advisory at 1100 AM AST.