1. The system is forecast to become a tropical storm as it moves over the northeastern Caribbean Sea today or tonight Tropical storm conditions are expected in portions of the U.S. Virgin Islands and Puerto Rico beginning this afternoon, and in the Dominican Republic by Wednesday. Tropical storm conditions are possible in northern Haiti and the southeastern Bahamas by late Wednesday.

2. Heavy rainfall could lead to flash, urban, and small stream flooding, along with possible rapid river rises and the potential for mudslides across the U.S. Virgin Islands and Puerto Rico. The greatest threat for flooding impacts will be across the eastern and southern portions of Puerto Rico.

3. There is a risk of wind and rainfall impacts elsewhere in portions of Hispaniola, the Bahamas, and Cuba later this week, although the forecast is more uncertain than usual since the system is still in its formative stage. Interests in these areas should monitor the system's progress and updates to the forecast.

4. Interests in Florida should monitor updates to the forecast for this system, but it is too soon to determine what if any impacts could occur there by late this week or this weekend given the uncertainty in the long-range forecast.

CHANGES WITH THIS ADVISORY:

The Government of France has discontinued the Tropical Storm Watch for Martinique and Guadeloupe.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
- Puerto Rico, including Culebra and Vieques
- U.S. Virgin Islands
- Dominican Republic on the south coast from Punta Palenque eastward and on the north coast from Cabo Frances Viejo eastward A Tropical Storm Watch is in effect for...
- Saba and St. Eustatius
- Dominican Republic on the north coast from Cabo Frances Viejo to the Dominican Republic/Haiti border
- Haiti from the northern border with the Dominican Republic to Gonaives
- Turks and Caicos Islands
- Southeastern Bahamas 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. Interests elsewhere in Haiti and the Bahamas, as well as in eastern and central Cuba, should monitor the progress of this system. 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 Six can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT1, WMO header WTNT41 KNHC and on the web at www.hurricanes.gov/graphics_at1.shtml?key_messages.

RAINFALL: The potential tropical cyclone is expected to produce the following rainfall amounts: Over the Leeward Islands, Virgin Islands, and Puerto Rico...2 to 4 inches, with isolated amounts of 6 inches. Heavy rainfall could lead to flash, urban, and small stream flooding, along with possible rapid river rises and the potential for mudslides across the U.S. Virgin Islands and Puerto Rico. Over the northern Windward Islands...1 to 3 inches. Over the Dominican Republic...3 to 6 inches.

WIND: Tropical storm conditions are possible within the watch area in the Lesser Antilles for the next few hours. Tropical storm conditions are expected in the warning areas in the U.S. Virgin Islands and Puerto Rico later today, and in the Dominican Republic by early Wednesday. Tropical storm conditions are possible elsewhere along the northern coasts of the Dominican Republic, northern Haiti, the Turks and Caicos, and the southeastern Bahamas beginning late Wednesday.

SURF: Swells generated by the disturbance are affecting portions of the Leeward Islands. These swells are expected to spread across the U.S. Virgin Islands and Puerto Rico today and reach portions of Hispaniola on Wednesday, where they could cause life threatening surf and rip current conditions. Please consult products from your local weather office.

At 1100 AM AST (1500 UTC), the disturbance was centered near latitude 16.3 North, longitude 63.8 West. The system is moving toward the west northwest near 18 mph (30 km/h) and this general motion is expected to continue during the next few days. On the forecast track, the disturbance is expected to pass near or over the U.S. Virgin Islands and Puerto Rico later today and tonight, be near or over Hispaniola on Wednesday, and be near the southeastern Bahamas and the Turks and Caicos Islands Thursday. Reports from a NOAA Hurricane Hunter aircraft indicate that maximum sustained winds are near 35 mph (55 km/h) with higher gusts. However, the aircraft did not find a well defined closed circulation. Gradual strengthening is forecast during the next day or so and the disturbance is expected to become a tropical storm later today or tonight. Some weakening is likely while the system interacts with Hispaniola on Wednesday. * Formation chance through 48 hours...high...90 percent. * Formation chance through 5 days...high...90 percent. The estimated minimum central pressure is 1012 mb (29.89 inches).

Satellite imagery shows that the disturbance has become better organized since yesterday, and satellite intensity estimates from TAFB and SAB are at tropical storm strength. However, reports from a NOAA Hurricane Hunter aircraft and surface observations indicate that the system does not yet have a well-defined closed circulation, with the wind and pressure fields more resembling an open wave, The maximum flight-level winds at 925 mb were 35-40 kt, and reliable SFMR wind estimates were near 30 kt. Based on these data, the system remains at potential tropical cyclone status with an initial intensity of 30 kt.

The initial motion remains west-northwestward or 295/16 kt. A strong low- to mid-level ridge to the north should steer the system generally west-northwestward for the next 72 h with some decrease in forward speed after 24 h. Beyond that time, a turn toward the northwest with an further decrease in forward speed is likely while the system moves near the western periphery of the ridge. The track guidance has changed little since the previous advisory. So, the new NHC track also has little change, and it lies near the various consensus models. Users are reminded that the average track errors at days 4 and 5 are 175 miles and 200 miles, respectively.

Conditions continue to appear favorable for strengthening before the system reaches Hispaniola in about 24 h, although there may be dry air entraining into the system in the southeastern quadrant. The intensity forecast will follow the previous prediction in calling for the disturbance to become a tropical storm before landfall, followed by weakening to a depression. The remainder of the intensity forecast has lower confidence due to possible land interaction with Cuba and differences in the upper-level wind forecasts among the various global models. The new intensity forecast will call for slow intensification from 60 h onward, similar to the previous one.