Monday, September 24, 2018

Isaac to weaken but could leave up to 4 inches of isolated rainfall in Puerto Rico

By on September 12, 2018

SAN JUAN – The National Hurricane Center (NHC) said Tropical Storm Isaac is expected to produce total rainfall accumulations of 1 to 2 inches with isolated amounts to 4 inches across Puerto Rico and the southern U.S. Virgin Islands, with up to an inch anticipated across the remaining Windward and Leeward Islands, although the system will experience a gradual weakening in the next few 72 hours.

Although Puerto Rico remains outside the forecast cone, the rainfall may cause life-threatening flash flooding.

At 2 p.m., “the center of Tropical Storm Isaac was located by a NOAA Hurricane Hunter aircraft and satellite near latitude 15.1 North, longitude 55.7 West. Isaac is moving faster toward the west near 21 mph (33 km/h), and this general motion with a decrease in forward is expected to continue through the weekend. On the forecast track, Isaac is forecast to move across the central Lesser Antilles and into the eastern Caribbean Sea on Thursday, and then move across the eastern and central Caribbean Sea through
Saturday.

“Aircraft data indicate that maximum sustained winds remain near 60 mph (95 km/h) with higher gusts. Gradual weakening is forecast during the next 72 hours.

“Tropical-storm-force winds extend outward up to 175 miles (280 km), primarily to the north of the center.

“The estimated minimum central pressure based on the aircraft data is 1002 mb (29.59 inches),” the National Weather Service’s public advisory reads.

A tropical storm warning was issued for Martinique, Dominica and Guadeloupe. A tropical storm watch is in effect for Antigua, Montserrat, St. Kitts and Nevis, Saba and St. Eustatius, and St. Martin and St. Maarten.

Tropical storm conditions are expected on Martinique, Dominica, and Guadeloupe early Thursday. Tropical storm conditions are possible within the tropical storm watch area on Thursday.

Isaac is expected to produce total rainfall accumulations of 2 to 4 inches with isolated amounts up 8 inches across Martinique, Dominica, and Guadeloupe. In relation to the winds, tropical storm conditions are expected in Martinique, Dominica and Guadeloupe early on Thursday. Tropical storm conditions are possible within the tropical storm monitoring area on Thursday.

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

“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,” the NHC warned.

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