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Tropical Storm Isaias Intermediate Advisory Number 8A
NWS National Hurricane Center Miami FL AL092020
800 AM AST Thu Jul 30 2020
...ISAIAS CAUSING LIFE-THREATENING FLASH FLOODING AND HIGH WINDS
OVER PUERTO RICO...
SUMMARY OF 800 AM AST...1200 UTC...INFORMATION
ABOUT 125 MI...205 KM W OF PONCE PUERTO RICO
ABOUT 105 MI...175 KM ESE OF SANTO DOMINGO DOMINICAN REPUBLIC
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 20 MPH...31 KM/H
MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Tropical Storm Warning is in effect for...
* Puerto Rico, Vieques, Culebra
* U.S. Virgin Islands
* British Virgin Islands
* 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
Interests in Cuba and the Florida peninsula should monitor the
progress of this system.
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
At 800 AM AST (1200 UTC), the center of Tropical Storm Isaias was
located near latitude 17.6 North, longitude 68.5 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 move over Hispaniola later
today and near the Southeastern Bahamas by tonight or early Friday.
Isaias is forecast to be near the Central Bahamas Friday night and
approach the Northwest Bahamas or southern Florida Friday night and
Maximum sustained winds are near 60 mph (95 km/h) with higher
gusts. Little change in strength is anticipated until landfall in
Dominican Republic later today, with re-strengthening forecast on
Friday and Saturday.
Tropical-storm-force winds extend outward up to 415 miles (665 km)
from the center. Tropical-storm-force winds are occuring along the
southern coast of Puerto Rico. A Weatherflow station in Yabucoa
Tanque de Agua reported sustained winds of 46 mph (74 km/h) with a
gust to 56 mph (91 km/h). A Weatherflow station at Las Mareas
reported sustained winds of 43 mph (69 km/h) with a gust to 54 mph
The estimated minimum central pressure is 1003 mb (29.62 inches).
HAZARDS AFFECTING LAND
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 across portions of
the U.S. and British Virgin Islands and Puerto Rico through this
morning or early afternoon. These conditions are forecast to reach
portions of the Dominican Republic and Haiti within the warning
area later this morning, and the southeastern Bahamas and Turks
and Caicos this afternoon. 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
British and U.S. Virgin Islands and Turks and Caicos: 3 to 6 inches.
Puerto Rico and northern Haiti: 3 to 6 inches, with isolated maximum
totals of 8 inches.
Dominican Republic: 4 to 8 inches, with isolated maximum totals of
Bahamas: 4 to 8 inches.
Cuba: 2 to 4 inches, with isolated maximum totals of 6 inches.
These rainfall amounts will lead to life-threatening flash flooding
and mudslides, as well as potential riverine flooding beginning
today. Urban and small stream flooding is expected for the U.S.
Virgin Islands, eastern Puerto Rico, and Hispaniola.
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.
Next complete advisory at 1100 AM AST.