Sunday, November 29, 2020

National Hurricane Center advisory on Tropical Storm Isaias

By on July 30, 2020

SAN JUAN — The National Hurricane Center issued the following:

Tropical Storm Isaias Intermediate Advisory Number 9A
NWS National Hurricane Center Miami FL AL092020
200 PM AST Thu Jul 30 2020

…ISAIAS BRINGING HEAVY RAINFALL AND TROPICAL-STORM-FORCE WINDS TO PORTIONS OF THE DOMINICAN REPUBLIC…

SUMMARY OF 200 PM AST…1800 UTC…INFORMATION
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LOCATION…18.9N 69.8W ABOUT 95 MI…150 KM WNW OF PUNTA CANA DOMINICAN REPUBLIC ABOUT 85 MI…140 KM SE OF PUERTO PLATA DOMINICAN REPUBLIC MAXIMUM SUSTAINED WINDS…60 MPH…95 KM/H PRESENT MOVEMENT…NW OR 310 DEGREES AT 20 MPH…31 KM/H MINIMUM CENTRAL PRESSURE…1003 MB…29.62 INCHES

WATCHES AND WARNINGS
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CHANGES WITH THIS ADVISORY:

The Tropical Storm Warning for Puerto Rico, Vieques, Culebra, and the U.S. Virgin Islands has been discontinued.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for… * Dominican Republic entire southern and northern coastlines * North coast of Haiti from Le Mole St Nicholas eastward to the northern border with the Dominican Republic * Turks and Caicos Islands * Southeastern Bahamas including the Acklins, Crooked Island, Long Cay, the Inaguas, Mayaguana, and the Ragged Islands * Central Bahamas, including Cat Island, the Exumas, Long Island, Rum Cay, and San Salvador

A Tropical Storm Watch is in effect for… * Northwestern Bahamas including Andros Island, New Providence, Eleuthera, Abacos Islands, Berry Islands, Grand Bahamas Island, and Bimini

Interests in Cuba and the Florida peninsula should monitor the progress of this system. Watches may be required for a portion of the Florida peninsula later today.

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, generally within 48 hours.

For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. For storm information specific to your area outside of the United States, please monitor products issued by your national meteorological service.

DISCUSSION AND OUTLOOK
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At 200 PM AST (1800 UTC), the center of Tropical Storm Isaias was located near latitude 18.9 North, longitude 69.8 West. Isaias is moving toward the northwest near 20 mph (31 km/h), and a west- northwestward to northwestward motion with some decrease in forward speed is expected over the next couple of days. On the forecast track, the center of Isaias will continue to move over Hispaniola through this evening, and be near the Southeastern Bahamas by late tonight or early Friday. Isaias is forecast to be near the Central Bahamas Friday night and move near or over the Northwest Bahamas or South Florida on Saturday.

Maximum sustained winds are near 60 mph (95 km/h) with higher gusts. Some slight weakening is possible as Isaias continues to move over Hispaniola today. Re-strengthening is forecast on Friday and Friday night.

Tropical-storm-force winds extend outward up to 310 miles (500 km) primarily to the north of the center. A weather station at Punta Cana near the eastern tip of the Dominican Republic reported sustained winds of 39 mph (63 km/h) with a gust to 52 mph (83 km/h) within the past couple of hours.

The estimated minimum central pressure is 1003 mb (29.62 inches).

HAZARDS AFFECTING LAND
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Key messages for Isaias can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT4, WMO header WTNT44 KNHC, and on the web at www.hurricanes.gov/text/MIATCDAT4.shtml.

WIND: Tropical storm conditions will continue to spread across portions of the Dominican Republic and Haiti within the warning area, and are expected to spread over the southeastern Bahamas and Turks and Caicos later today. Tropical storm conditions are expected in the Central Bahamas beginning Friday morning and are possible in the northwestern Bahamas beginning late Friday.

RAINFALL: Isaias is expected to produce the following rain accumulations:

Puerto Rico, Dominican Republic and northern Haiti: 4 to 8 inches, with isolated maximum totals of 10 inches.

Bahamas, Turks and Caicos: 4 to 8 inches.

Cuba: 1 to 2 inches, with isolated maximum totals of 4 inches.

These rainfall amounts will lead to life-threatening flash flooding and mudslides, as well as river flooding. Urban and small stream flooding is expected for the U.S. Virgin Islands, eastern and southwestern Puerto Rico, and Hispaniola.

Heavy rains associated with Isaias may begin to affect South Florida Saturday morning. This rain could result in isolated flash and urban flooding, especially in low-lying and poorly drained areas.

SURF: Swells generated by Isaias are affecting portions of the Leeward Islands, the Virgin Islands, Puerto Rico, the Dominican Republic, the Turks and Caicos Islands and the southeastern Bahamas. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office.

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