NWS National Hurricane Center Miami
800 AM AST Thu Sep 13 2018
…TROPICAL-STORM-FORCE WINDS EXPECTED SOON IN THE LEEWARD ISLANDS…
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 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 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 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.
Source: The Daily Herald https://www.thedailyherald.sx/islands/80588-tropical-storm-isaac-intermediate-advisory-number-23a