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Tropical Storm Isaias Advisory Number 11
NWS National Hurricane Center Miami FL AL092020
1100 PM EDT Thu Jul 30 2020
...ISAIAS NEARING THE SOUTHEASTERN BAHAMAS...
SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
ABOUT 95 MI...150 KM ESE OF GREAT INAGUA ISLAND
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Hurricane Warning is in effect for...
* Northwestern Bahamas including Andros Island, New Providence,
Eleuthera, Abacos Islands, Berry Islands, Grand Bahamas Island, and
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...
* East coast of Florida from Ocean Reef to Sebastian Inlet
* Lake Okeechobee
Interests elsewhere along the southeast coast of the United
States should monitor the progress of this system. Additional
watches or warnings may be required for a portion of the Florida
peninsula on Friday.
A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area. A warning is typically issued
36 hours before the anticipated first occurrence of
tropical-storm-force winds, conditions that make outside
preparations difficult or dangerous. Preparations to protect life
and property should be rushed to completion.
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 1100 PM EDT (0300 UTC), the center of Tropical Storm Isaias was
located near latitude 20.5 North, longitude 71.9 West. Isaias is
moving toward the northwest near 18 mph (30 km/h), and a
generally northwestward motion with some decrease in forward
speed is expected for the next couple of days followed by turn
toward the north-northwest. On the forecast track, the center of
Isaias will move near or over the Southeastern Bahamas by late
tonight. Isaias is forecast to be near the Central Bahamas Friday
night and move near or over the Northwestern Bahamas and near South
Florida on Saturday.
Maximum sustained winds are near 60 mph (95 km/h) with higher gusts.
Strengthening is forecast during the next day or so, and Isaias is
forecast to become a hurricane by Friday night.
Tropical-storm-force winds extend outward up to 240 miles (390 km)
from the center. An unofficial observing station on Big Ambergris
Cay in the Turks and Caicos Islands recently reported a sustained
wind of 43 mph (69 km/h) and had a gust to 54 mph (87 km/h) a few
The estimated minimum central pressure is 999 mb (29.50 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.
STORM SURGE: A dangerous storm surge will raise water levels by as
much as 3 to 5 feet above normal tide levels in areas of onshore
winds in the central and northwestern Bahamas. Storm surge will
raise water level by as much as 1 to 3 ft above normal tide levels
in the southeastern Bahamas.
WIND: Tropical storm conditions will continue to spread across
portions of the Dominican Republic, Haiti, the southeastern Bahamas
and Turks and Caicos tonight and early Friday. Tropical storm
conditions are expected to begin in the central Bahamas Friday
morning and spread into the northwestern Bahamas beginning late
Friday. Hurricane conditions are expected within portions of the
the northwestern Bahamas Friday night and Saturday.
Tropical storm conditions are possible in the watch area in Florida
RAINFALL: Isaias is expected to produce the following rain
accumulations through Friday night:
Dominican Republic and northern Haiti: 4 to 8 inches, with isolated
maximum totals of 12 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 and Hispaniola.
From Friday night through Monday:
South Florida into east-Central Florida: 2 to 4 inches, with
isolated maximum totals of 6 inches.
These rainfall amounts 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 will spread along the coast of Cuba and into
the central and northwestern Bahamas over the next day or two.
These swells are likely to cause life-threatening surf and rip
current conditions. Please consult products from your local
Next intermediate advisory at 200 AM EDT.
Next complete advisory at 500 AM EDT.