1. The system is forecast to become a tropical storm as it moves over the northeastern Caribbean Sea today. 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 and potential mudslides across the U.S. Virgin Islands and Puerto Rico. The greatest threat for flooding impacts will be across the eastern and southeastern 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 the remainder of the Bahamas and 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 the Bahamas has issued a Tropical Storm Watch for the Turks and Caicos Islands, and for the southeastern Bahamas, including the Acklins, Crooked Island, Long Cay, the Inaguas, Mayaguana, and the Ragged Islands. 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...
- Martinique and Guadeloupe
- Dominica
- 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. For storm information specific to your area, 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 and potential 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 across portions of Hispaniola on Wednesday, and they could cause life threatening surf and rip current conditions. Please consult products from your local weather office.

At 500 AM AST (0900 UTC), the disturbance was centered near latitude 15.7 North, longitude 62.2 West. The system is moving toward the west northwest near 17 mph (28 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 late today and tonight, and be near or over Hispaniola on Wednesday. Maximum sustained winds remain near 35 mph (55 km/h) with higher gusts. Gradual strengthening is forecast during the next day or so and the disturbance is expected to become a tropical storm later this morning. 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 1010 mb (29.83 inches).

The disturbance moved through the southern Leeward Islands a few hours ago. Based on surface observations from the islands, the system still does not have a well-defined circulation. Although the satellite appearance shows some increase in organization, the surface data suggest no significant strengthening has occurred thus far. The current intensity estimate is held at 30 kt in agreement with a Dvorak estimate from SAB. A NOAA Hurricane Hunter aircraft is scheduled to investigate the disturbance later this morning and should provide an updated intensity estimate, and also determine whether the system has become a tropical cyclone.

The disturbance continues moving west-northwestward, or about 295/15 kt. The flow on the south side of a strong subtropical ridge should maintain the west-northwestward track for the next 72 hours or so, with some slowing of forward speed by midweek. Beyond that time, a turn toward the northwest with further deceleration is likely while the system moves near the western periphery of the ridge. The official track forecast is very similar to the previous one and in good agreement with the latest simple and corrected multi-model consensus tracks. Users are reminded that the average track errors at days 4 and 5 are 175 miles and 200 miles, respectively.

Dynamical conditions appear to be conducive for intensification during the next 24 hours or so, with low vertical shear and pronounced upper-level outflow over the system. The main hindrance for strengthening today and tonight appears to be some dry mid-tropospheric air in the environment, as shown by the global models. Since the projected track takes the disturbance or cyclone over the mountainous land mass of Hispaniola, some weakening and disruption of the circulation is likely in 36 hours or so. Later in the forecast period, the dynamical guidance shows some increase in westerly shear which could also inhibit strengthening. The official intensity forecast closely follows the NOAA corrected consensus forecast technique, HCCA. There is significant uncertainty in 4-5 day intensity forecasts, however.