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Potential Tropical Cyclone Nine Intermediate Advisory Number 1A
NWS National Hurricane Center Miami FL AL092020
200 PM AST Tue Jul 28 2020
...AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT BEGINNING TO
INVESTIGATE THE DISTURBANCE...
...SYSTEM EXPECTED TO BRING HEAVY RAINFALL AND
TROPICAL-STORM-CONDITIONS TO THE LEEWARD ISLANDS...
SUMMARY OF 200 PM AST...1800 UTC...INFORMATION
ABOUT 510 MI...820 KM ESE OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 23 MPH...37 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The government of Barbados has issued a Tropical Storm Warning for
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. Maartin
A Tropical Storm Watch is in effect for...
* Dominican Republic from Cabo Engano to the northern border with
Interests elsewhere in the Leeward Islands and Hispaniola 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 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 PM AST (1800 UTC), the disturbance was centered near latitude
14.1 North, longitude 54.8 West. The system is moving toward the
west near 23 mph (37 km/h), and this general motion with some
reduction in forward speed is expected over the next few days. On
the forecast track, the system is forecast to move through the
Leeward Islands on Wednesday, near or over the Virgin Islands and
Puerto Rico Wednesday night, and near or over Hispaniola on
Maximum sustained winds are near 40 mph (65 km/h) with higher
gusts. Some strengthening is expected during the next 48 hours, and
the system is forecast to become a tropical storm tonight or
Environmental conditions are expected to be conducive for
additional development and a tropical storm is forecast to form
tonight or Wednesday. An Air Force Reserve reconnaissance aircraft
is currently investigating the system.
* 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)
primarily to the northeast of the center.
The estimated minimum central pressure is 1007 mb (29.74 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 on Wednesday and spread into the U.S. and British Virgin
Islands and Puerto Rico Wednesday afternoon through Thursday
morning. These conditions could begin reach portions of the north
coast of the Dominican Republic early Thursday.
RAINFALL: The potential tropical cyclone will produce total rain
accumulation of 3 to 6 inches with maximum amounts of 10 inches
across the northern Leeward Islands, British and U.S. Virgin
Islands and Puerto Rico. Rainfall accumulations of 2 to 4 inches
possible across the Windward Islands. This rainfall may produce
life threatening flash flooding and mudslides, as well as potential
Next complete advisory at 500 PM AST.