1. Tropical storm conditions are expected over the Virgin Islands and Puerto Rico on Sunday. Tropical storm conditions are possible over eastern parts of the Dominican Republic Sunday night and Monday.

2. Heavy rainfall could lead to flash and urban flooding over the Leeward and Virgin Islands, Haiti and the Dominican Republic. Across Puerto Rico, heavy rainfall may lead to flash, urban and small stream flooding, along with the potential for mudslides.

3. There is a risk of wind and rainfall impacts across the rest of the Dominican Republic, Haiti, the Turks and Caicos Islands, the Bahamas, Cuba, and Florida next week, but forecast uncertainty remains higher than usual. Interests in those areas should monitor the progress of Grace and updates to the forecast.

CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
- Saba and Sint Eustatius
- Sint Maarten
- St. Martin and St. Barthelemy
- U.S. Virgin Islands
- Puerto Rico, including Vieques and Culebra
- Dominican Republic from Cabo Caucedo to Samana

A Tropical Storm Watch is in effect for...
- South coast of the Dominican Republic from the Haitian border to Cabo Caucedo
- North coast of the Dominican Republic from the Haitian border to Samana
- Entire coast of Haiti

A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area.

A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours.

Interests elsewhere in the Dominican Republic, Haiti, the Turks and Caicos Islands, the southeastern Bahamas, and Cuba should monitor the progress of Grace. Additional watches and warnings could be required for some of these areas later today.

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 Grace can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT2 and WMO header WTNT42 KNHC and on the web at www.hurricanes.gov/graphics_at2.shtml?key_messages.

WIND: Tropical storm conditions are expected within the warning area in the Leeward Islands this morning, in the Virgin Islands and Puerto Rico today, and in the Dominican Republic tonight. Tropical storm conditions are possible within the watch area in the Dominican Republic tonight and Monday, and in Haiti on Monday night.

RAINFALL: Grace is expected to produce the following rainfall amounts Saturday into Tuesday:

Over the northern Leeward Islands and Virgin Islands...3 to 6 inches. This rainfall may produce scattered areas of flash and urban flooding.

Over Puerto Rico...3 to 6 inches with isolated maximum totals of 8 inches. Heavy rainfall could lead to flash, urban and small stream flooding and possible mudslides.

Over Haiti and the Dominican Republic...4 to 7 inches with isolated maximum totals of 10 inches. Heavy rainfall could lead to flash and urban flooding and possible mudslides from Monday into Tuesday.

By mid to late next week heavy rainfall from this system could affect portions of Cuba, the Bahamas and Florida.

At 200 AM AST (0600 UTC), the center of Tropical Storm Grace was located near latitude 16.7 North, longitude 63.7 West. Grace is now moving toward the westnorthwest near 22 mph (35 km/h). A continued westnorthwestward motion with a gradual decrease in forward speed is expected during the next several days. On the forecast track, the center of Grace is expected to pass near the Virgin Islands and Puerto Rico today, near or over the Dominican Republic tonight and Monday, and then move near or over Haiti Monday night.

Maximum sustained winds remain near 40 mph (65 km/h) with higher gusts. Some strengthening is forecast during the next day or so. Grace is likely to weaken while it moves near and across the Greater Antilles Monday and Tuesday.

Tropicalstormforce winds extend outward up to 35 miles (55 km) from the center.

The estimated minimum central pressure is 1010 mb (29.83 inches).

Grace is a poorly organized tropical cyclone. Trying to pinpoint the center of the storm over the last 6-12 hours has been a challenge, even with the help of earlier NOAA aircraft, surface observations, and radar data from Guadalupe. Earlier data from the NOAA aircraft reconnaissance Twin Doppler Radar showed that the mid-level center was tilted significantly further southeast relative to the poorly-defined low-level circulation. Around 0000 UTC, multiple reporting stations in Guadalupe showed a wind shift to the west, and there were some skeletal bands seen on the nearby Guadalupe radar ahead of a convective squall propagating ahead, which is currently producing the coldest cloud tops with Grace. Given all of these data, the center of Grace is estimated to have passed by just north of Guadalupe over the last few hours. Despite the higher subjective and objective Dvorak estimates, the initial intensity was kept at 35 kt for this advisory given the lackluster wind data from the earlier NOAA aircraft reconnaissance mission.

Grace appears to have reformed a bit further North tonight, and also now appears to be on a somewhat slower west-northwest heading, at 285/17 kt. There remains a large amount of spread in the guidance, even in the short-term, which is likely related to the current disorganized nature of Grace. In general, Grace is expected to maintain a west-northwestward motion and gradually slow down over the next 24-36 hours. A strong low- to mid-level ridge poleward of Grace should then maintain this west-northwest heading through the remainder of the forecast. A lot of the track uncertainty in the latter part of the forecast appears to be related to the future intensity of the storm, and both the ECMWF and GFS ensembles show a large north-to-south spread with stronger members tracking further north and weaker members tracking further south. For now, the NHC track forecast has been shifted north of the previous track, mostly related to the further north initial position, and is in close agreement with the HFIP corrected-consensus approach (HCCA) model.

Grace appears to finally be slowing down a bit this evening, but will still need to slow down a bit more in order to allow the low- to mid-level centers to become better aligned. Because of this disjointed structure, only slow intensification is anticipated. The latest intensity guidance is a bit lower, and the NHC intensity guidance follows suit, with a peak intensity of 45-kt in 24 hours. Thereafter, it appears likely that Grace will have to deal with significant land interaction over Hispaniola and weakening is indicated by 48 hours. If Grace survives, it is possible some modest intensification could occur in the latter part of the forecast period. The intensity forecast remains closely tied to the track forecast, and any deviations to the north or south could allow Grace to stay stronger than indicated in this forecast. However, it also remains distinctly possible that Grace could dissipate before the end of this 5-day forecast due to the forecasted land interaction.

As previously mentioned, the exact track of the center and the intensity of the system will likely not be as important as the heavy rainfall that is forecast to fall across the Leeward Islands and the Greater Antilles during the next few days.