ZCZC MIATCPAT4 ALL
TTAA00 KNHC DDHHMM
Potential Tropical Cyclone Nine Intermediate Advisory Number 4A
NWS National Hurricane Center Miami FL AL092020
800 AM AST Wed Jul 29 2020
...HEAVY RAINFALL AND GUSTY WINDS SPREADING OVER THE LEEWARD
SUMMARY OF 800 AM AST...1200 UTC...INFORMATION
ABOUT 55 MI...90 KM WSW OF DOMINICA
ABOUT 350 MI...560 KM SE OF SAN JUAN PUERTO RICO
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 23 MPH...37 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The government of Barbados has discontinued the Tropical Storm
Warning for Dominica.
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
* North coast of Haiti from Le Mole St Nicholas eastward to the
northern border with the Dominican Republic
A Tropical Storm Watch is in effect for...
* Dominican Republic from the southern Haiti border eastward to
* Turks and Caicos Islands
* Southeastern Bahamas
Interests in the central and northwestern Bahamas and Cuba 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 disturbance was centered near latitude
15.1 North, longitude 62.1 West. The system is moving toward the
west-northwest 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 will move near or over Puerto Rico
tonight, near or over Hispaniola on Thursday, and near or over the
southeastern Bahamas on Friday.
Maximum sustained winds remain near 45 mph (75 km/h) with higher
gusts. Some increase in strength is forecast today, with weakening
likely on Thursday due to land interaction, and some restrengthening
possible late week.
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 275 miles (445 km)
primarily to the north and northeast of the center. A wind gust of
46 mph (74 km/h) was recently reported on St. Kitts.
The estimated minimum central pressure is 1005 mb (29.68 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 moving across portions of the
Leeward Islands and will 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 and Haiti within the warning area early
Thursday. Tropical storm conditions are possible in the watch areas
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, northern Haiti and the Turks and
Caicos: 3 to 6 inches, with isolated maximum totals of 8 inches.
Across the Inagua Islands: 4 to 8 inches, with isolated totals of
These rainfall amounts could lead to life threatening flash flooding
and mudslides, as well as potential riverine flooding.
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 swells 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 1100 AM AST.