1. Heavy rainfall across the Dominican Republic, Haiti, Cuba, Jamaica, the Cayman Islands, and the northern Yucatan Peninsula may lead to flash, urban, and small stream flooding, with the potential for mudslides highest in Haiti and the Dominican Republic.

2. Tropical storm conditions are possible over portions of Hispaniola and over Jamaica on today. Tropical storm conditions are expected over portions of the southern coast of Cuba today, spreading westward to the Cayman Islands and possibly other portions of the southern coast of Cuba this evening through Wednesday morning.

3. There is a increasing risk of wind, rainfall, and storm surge impacts on the Yucatan Peninsula of Mexico Wednesday night and Thursday. Interests there areas should monitor the progress of Grace and updates to the forecast.

CHANGES WITH THIS ADVISORY: The government of Mexico has issued a Hurricane Watch for portions of the Yucatan Peninsula from Cabo Catoche southward to Punta Allen. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Hurricane Watch is in effect for...
- Yucatan Peninsula of Mexico from Cabo Catoche to Punta Allen A Tropical Storm Warning is in effect for...
- Southern coast of the Cuban provinces of Santiago de Cuba, Granma, Las Tunas, and Camaguey
- Cayman Islands A Tropical Storm Watch is in effect for...
- Entire coast of Haiti
- Jamaica
- Southern coast of the Cuban provinces of Ciego de Avila, Sancti Spiritus, Cienfuegos, Matanzas, and Pinar del Rio, as well as Isla de la Juventud. A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical storm force winds, conditions that make outside preparations difficult or dangerous. 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. Interests elsewhere in the Yucatan Peninsula of Mexico should monitor the progress of Grace. Additional watches or warnings may be required for portions of the Yucatan coast later today. For storm information specific to your area, 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, WMO header WTNT42 KNHC and on the web at www.hurricanes.gov/graphics_at2.shtml?key_messages.

WIND: Tropical storm conditions are possible in Haiti early this morning, and in Jamaica this afternoon. Tropical storm conditions are expected along the southern coast of Cuba within the warning area this afternoon and evening, and over the Cayman Islands beginning tonight into early Wednesday. Tropical storm conditions are possible along the southern coast of Cuba within the watch area tonight and Wednesday.

RAINFALL: Grace is expected to produce the following rainfall amounts: Over Haiti...5 to 10 inches of rain with isolated maximum totals of 15 inches are expected across the southern terrain areas today. This heavy rainfall should lead to flash and urban flooding, and possible mudslides. Over far southern Cuba, Jamaica, the Cayman Islands, and portions of the Yucatan Peninsula....3 to 6 inches of rain with isolated maximum totals of 9 inches are expected through Thursday. This heavy rainfall may lead to flash and urban flooding.

SURF: Swells generated by Grace will continue to affect portions of Hispaniola over the next day or so, and will spread westward to Jamaica, the Cayman Islands, the southern coast of Cuba, and the Yucatan Peninsula of Mexico. These swells are likely to cause life threatening surf and rip current conditions. Please consult products from your local weather office.

At 500 AM EDT (0900 UTC), the center of Tropical Storm Grace was located near latitude 18.2 North, longitude 75.4 West. Grace is moving toward the west near 16 mph (26 km/h). A general westward to west northwestward motion is expected for the next several days. On the forecast track, the center of Grace will move near the northern coast of Jamaica this afternoon. Grace is forecast to move near the Cayman Islands tonight, and then approach the Yucatan peninsula of Mexico late Wednesday or early Thursday. Maximum sustained winds recently reported by an Air Force Reserve reconnaissance aircraft were near 40 mph (65 km/h) with higher gusts. Gradual strengthening is forecast during the next couple of days, and Grace could be near hurricane strength when it approaches the Yucatan coast of Mexico late Wednesday and early Thursday Tropical storm force winds extend outward up to 45 miles (75 km) from the center. The estimated minimum central pressure is 1005 mb (29.68 inches).

An Air Force Reserve reconnaissance aircraft had difficulty locating the center of Grace early this morning. The last few visible satellite images along with 0200Z ASCAT wind data indicated that a lee-side surface low had formed south of the western tip of Haiti. That feature has gradually been pulling northward closer to the deep convection that has developed near the well-defined mid-level circulation center. The initial position is the midpoint between the recon position in the latest vortex message and the mid-level circulation noted in passive microwave imagery. The aircraft also found some patches of 925-mb flight-level winds of 48-51 kt, which equates to surface winds of 36-38 kt. Reliable SFMR surface winds obtained by the aircraft were also in the 36-38-kt range. Based on these data, Grace was upgraded back to a 35-kt tropical storm at 0600 UTC. Regardless of Grace's exact intensity right now, the immediate threat is still torrential rainfall across western Hispaniola today and over Jamaica this afternoon and tonight, which will likely cause severe flooding in some locations.

The initial motion estimate is an uncertain 280/14 kt. A strong mid-level ridge is forecast to build westward across Florida and the Gulf of Mexico during the next several days, which should keep Grace on a westward or west-northwestward track through the 120-h forecast period. Only a very sight southward shift in the previous forecast track was made, which was due primarily to the new estimated southerly initial position, and the new NHC forecast track lies along the northern edge of model guidance envelope.

Once Grace passes Jamaica in 12-18 hours, the cyclone will be passing over water temperatures near 30 deg C and into a more divergent upper-level wind flow pattern. These two favorable conditions should allow for Grace to slowly intensify and possibly be near hurricane strength by the time the cyclone reaches the Yucatan peninsula in about 48 hours. Thereafter, Grace will weaken as it pass over Yucatan, and then re-strengthen some over the Bay of Campeche before reaching mainland Mexico in about 96 hours. The NHC intensity forecast is close to a blend of the HCCA and IVCN consensus models.