1. Potential Tropical Cyclone Nine will produce heavy rains and potentially life-threatening flash flooding and mudslides across the northern Leeward Islands, the Virgin Islands, Puerto Rico, and the Dominican Republic. 2. Tropical storm conditions are likely across portions of the Leeward Islands, the Virgin Islands, and Puerto Rico today and will spread westward to portions of the Dominican Republic, Haiti, and the southeastern Bahamas and Turks and Caicos on Thursday and Thursday night. Tropical Storm Warnings are in effect for these areas. Do not focus on the details of the track forecast, as rainfall and wind hazards will extend far from the center of the system. 3. The details of the long-range track and intensity forecasts remain more uncertain than usual since the system does not have a well-defined center and it is expected to move near or over portions of the Greater Antilles later this week. However, this system could bring some rainfall and wind impacts to portions of Cuba, the central and northwest Bahamas, and Florida later this week and this weekend. Interests there should monitor its progress and updates to the forecast over the next few days.

CHANGES WITH THIS ADVISORY:

The government of the Dominican Republic has issued a Tropical Storm Warning along the south coast of the Dominican Republic west of Cabo Caucedo to the border with Haiti. The government of Antigua has discontinued the Tropical Storm Warning for Antigua and Barbuda. The government of France has discontinued the Tropical Storm Warning for Martinique and Guadeloupe.

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
- Montserrat, St. Kitts, Nevis, and Anguilla
- St. Martin, and St. Barthelemy
- Saba and St. Eustatius
- St. Maarten
- 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

A Tropical Storm Watch is in effect for...
- Central Bahamas, including Cat Island, the Exumas, Long Island, Rum Cay, and San Salvador

Interests in the 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.

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 www.hurricanes.gov/text/MIATCDAT4.shtml.

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, and the southeastern Bahamas and Turks and Caicos Thursday afternoon. Tropical storm conditions are possible in the watch areas on Thursday and Friday.

RAINFALL: The disturbance 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 10 inches.

Across the Dominican Republic, northern Haiti, and 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 12 inches.

These rainfall amounts may lead to lifethreatening 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 and eastern Puerto Rico.

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, the Turks and Caicos Islands and the southeastern Bahamas tonight or Thursday. These swells are likely to cause lifethreatening surf and rip current conditions. Please consult products from your local weather office.

At 200 PM AST (1800 UTC), the disturbance was centered near latitude 16.2 North, longitude 64.7 West. The system is moving toward the westnorthwest near 23 mph (37 km/h), and this general motion with a reduction in forward speed is expected over the next few days. On the forecast track, the system will move near or just south of Puerto Rico later today and tonight, near or over Hispaniola on Thursday, and near or over eastern Cuba on Friday.

Maximum sustained winds are near 45 mph (75 km/h) with higher gusts. Some increase in strength is forecast through tonight, with weakening likely on Thursday due to land interaction. Some restrengthening is possible by this weekend. A wind gust of 44 mph (71 km/h) was recently reported at the Luis Munoz Marin International Airport in San Juan. A wind gust of 44 mph mph (71 km/h) was also reported at St. Thomas in the U.S. Virgin Islands within the past few hours. In St. Maarten, a wind gust to 51 mph (81 km/h) was observed late this morning.

Environmental conditions are expected to be conducive for additional development, and a tropical storm is forecast to form later today or tonight. * Formation chance through 48 hours...high ...90 percent * Formation chance through 5 days...high...90 percent Tropicalstormforce winds extend outward up to 275 miles (445 km) primarily to the north and northeast of the center.

The estimated minimum central pressure is 1006 mb (29.71 inches).

Surface observations from the Lesser Antilles show that the broader circulation of the disturbance has become slightly better defined but a recent Air Force Reserve reconnaissance aircraft was still unable to find a well-defined circulation. Therefore, the system has not yet become a tropical cyclone. The aircraft measured peak flight-level winds of 46 kt and several SFMR winds of around 35 kt, so the initial intensity remains 40 kt for this advisory.

The system continues moving briskly west-northwestward at 290/20 kt. The forecast reasoning remains unchanged as a ridge to the north of the system is expected to steer the disturbance west-northwestward during the next couple of days. This motion should bring the system near or over Hispaniola on Thursday and near eastern Cuba Thursday night and Friday. The ridge is forecast to weaken by the weekend which should cause a reduction in forward speed. It still must be stressed that since the system lacks a well-defined center and remains in its formative stage, uncertainty in the specifics of the track forecast remain high in both the short and longer range. The latest NHC track foreast has been nudged slightly south of the previous advisory and lies between the latest ECMWF solution and the various consensus aids. Deep convection has consolidated and there is some evidence of banding over the northern and western portions of the large circulation. As a result, the system is still expected to become a tropical storm later today or tonight. Some additional intensification is then possible before the system reaches Hispaniola on Thursday, but weakening is likely to occur while it interacts with land. After that time, the system's close proximity to eastern Cuba and an expected increase in southwesterly shear are likely to inhibit significant re-strengthening. The latest NHC wind speed forecast has been lowered from the previous advisory at 72-120 h. Given the expected land interaction and less than ideal upper-level environment it is best to remain conservative at this time.

Interests in Hispaniola, the Bahamas, Cuba, and Florida should continue to monitor forecasts as changes to both the track and intensity are likely.