1. The system is forecast to become a tropical storm as it moves through the Leeward Islands tonight, and tropical storm conditions are possible there. Tropical storm conditions are expected in portions of the U.S. Virgin Islands and Puerto Rico beginning Tuesday afternoon, and in the Dominican Republic by Wednesday. Tropical storm conditions are possible in northern Haiti 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 Turks and Caicos, the southeastern 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.

ISSUED... SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION LOCATION...15.1N 60.8W ABOUT 40 MI...65 KM ESE OF DOMINICA ABOUT 90 MI...150 KM SSE OF GUADELOUPE MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H PRESENT MOVEMENT...WNW OR 295 DEGREES AT 16 MPH...26 KM/H MINIMUM CENTRAL PRESSURE...1010 MB...29.83 INCHES WATCHES AND WARNINGS CHANGES WITH THIS ADVISORY: The Tropical Storm Watch for the U.S. Virgin Islands, Puerto Rico, Culebra, and Vieques has been upgraded to a Tropical Storm Warning. The government of the Dominican Republic has issued a Tropical Storm Warning on the south coast from Punta Palenque eastward and on the north coast from Cabo Frances Viejo eastward. A Tropical Storm Watch has been issued for northern Haiti from the border with the Dominican Republic to Gonaives. 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 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. This 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 overnight. Tropical storm conditions are expected in the warning areas in the U.S. Virgin Islands and Puerto Rico on Tuesday, and in the Dominican Republic by early Wednesday. Tropical storm conditions are possible elsewhere along the northern coasts of the Dominican Republic and northern Haiti 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 on Tuesday 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 1100 PM AST (0300 UTC), the disturbance was centered near latitude 15.1 North, longitude 60.8 West. The system is moving toward the west northwest near 16 mph (26 km/h) and this general motion is expected to continue during the next few days. On the forecast track, the disturbance is expected to move across the southern Leeward Islands during the next few hours, pass near or over the U.S. Virgin Islands and Puerto Rico late Tuesday and Tuesday night, 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 two and the disturbance is expected to become a tropical storm overnight. * Formation chance through 48 hours...high...90 percent. * Formation chance through 5 days...high...90 percent. The estimated minimum central pressure based on surface observations is 1010 mb (29.83 inches).

The disturbance is now very near the Leeward Islands and it is expected to produce gusty winds and heavy rains across portions of those islands during the next several hours. Satellite and radar data indicate that deep convection continues to gradually organize in curved bands across the northern half of the circulation, but the system still seems to lack a well-defined center. Therefore, the disturbance remains a potential tropical cyclone for now. The initial intensity is held at 30 kt based on Dvorak estimates from TAFB and SAB.

The system is moving west-northwestward at about 14 kt. The main steering feature for the system will continue to be the subtropical ridge that is situated to its north across the central and western Atlantic. The flow on the south side of the ridge should keep the depression moving relatively briskly to the west-northwest during the next couple of days, taking it across the Leeward Islands overnight, near or over the U.S. Virgin Islands and Puerto Rico Tuesday and Tuesday night, and then near or over Hispaniola on Wednesday. Beyond that time, the storm is forecast to gradually slow down, when it nears the southwestern portion of the ridge, as it moves near Cuba and the Bahamas late this week. By the weekend, most of the models show the depression reaching a weakness in the ridge, which will likely cause a gradual turn to the right near the Florida Keys or southern Florida. The models are in quite good agreement, especially during the next 3 or 4 days, and the NHC track forecast 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.

The disturbance is currently in conducive conditions for intensification with the cyclone currently over fairly warm 28 C waters and in low wind shear conditions. The only negative factor for the storm is some dry air in its vicinity. Overall, these environmental factors, and the model guidance, support strengthening during the next 24 hours or so, but the potential land interaction with Puerto Rico could limit the amount of intensification. By Wednesday, the potential land interaction with the mountainous island of Hispaniola and an increase in westerly shear should cause some weakening. However, the environmental conditions could become more favorable for strengthening again by the end of the week, which is the reason why the forecast shows slightly higher wind speeds at those time periods. The NHC intensity forecast generally follows the IVCN and HCCA models, which are typically the most skillful aids. It should be noted that the intensity forecast is of low confidence since the cyclone's future strength will be quite dependent on the exact track and the degree of land interaction.