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Potential Tropical Cyclone Nine Intermediate Advisory Number 3A
NWS National Hurricane Center Miami FL AL092020
200 AM AST Wed Jul 29 2020
...HEAVY RAINFALL AND GUSTY WINDS AFFECTING THE LESSER ANTILLES...
SUMMARY OF 200 AM AST...0600 UTC...INFORMATION
ABOUT 50 MI...80 KM ENE OF MARTINIQUE
ABOUT 450 MI...725 KM ESE OF SAN JUAN PUERTO RICO
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 25 MPH...41 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...
* Puerto Rico, Vieques, Culebra
* U.S. Virgin Islands
* British Virgin Islands
* Antigua, Barbuda, Montserrat, St. Kitts, Nevis, and Anguilla
* Guadeloupe, Martinique, St. Martin, and St. Barthelemy
* Saba and St. Eustatius
* St. Maarten
* Dominican Republic from Cabo Caucedo eastward to Cabo Engano and
then westward along the northern coast to the Dominican
A Tropical Storm Watch is in effect for...
* Dominican Republic from the southern Haiti border eastward to
* Turks and Caicos Islands
Interests elsewhere in the southeast and central Bahamas 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 200 AM AST (0600 UTC), the disturbance was centered near latitude
14.9 North, longitude 60.3 West. The system is moving toward the
west-northwest near 25 mph (41 km/h), and this general motion with
some slight reduction in forward speed is expected over the next few
days. On the forecast track, the center will move through the
southern Leeward Islands during the next few hours, near or over the
Virgin Islands and Puerto Rico Wednesday night, and near or over
Hispaniola on Thursday.
Maximum sustained winds are near 45 mph (75 km/h) with higher
gusts. Some strengthening is expected during the next 48 hours, and
the system is forecast to become a tropical storm today.
Environmental conditions are expected to be conducive for
additional development, and a tropical storm is forecast to form
* Formation chance through 48 hours...high...90 percent
* Formation chance through 5 days...high...90 percent
Tropical-storm-force winds extend outward up to 230 miles (370 km),
north of the center.
The estimated minimum central pressure based on Air Force Reserve
Hurricane data is 1006 mb (29.71 inches).
HAZARDS AFFECTING LAND
Key messages for Potential Tropical Cyclone Nine can be found in
the Tropical Cyclone Discussion under AWIPS header MIATCDAT4, WMO
header WTNT44 KNHC, and on the web at
WIND: Tropical storm conditions are expected to reach the Leeward
Islands during the next few hours, and spread across the U.S. and
British Virgin Islands and Puerto Rico this afternoon through
Thursday morning. These conditions are forecast to reach portions
of the Dominican Republic within the warning area early Thursday.
Tropical storm conditions are possible in the watch areas on
RAINFALL: The potential tropical cyclone is expected to produce the
following rain accumulations:
Across the northern Leeward Islands, British and U.S. Virgin
Islands: 3 to 6 inches.
Across Puerto Rico: 3 to 6 inches, with isolated maximum totals of
Across the Dominican Republic: 3 to 6 inches, with isolated maximum
totals of 8 inches.
These rainfall amounts could lead to life threatening flash flooding
and mudslides, as well as potential riverine flooding.
Rainfall is also expected in the following locations:
Across the Windward Islands: 1 to 3 inches.
SURF: Swells generated by Potential Tropical Cyclone Nine will be
affecting portions of the Leeward Islands, the Virgin Islands and
Puerto Rico during the next day or two. These dangerous conditions
are forecast to reach the north coast of the Dominican Republic and
the Turks and Caicos Islands and the southeastern Bahamas on
Thursday. 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 500 AM AST.