1. Hurricane conditions and a dangerous storm surge are expected over portions of the Hurricane Warning area in the eastern Yucatan Peninsula of Mexico beginning late Wednesday night.

2. Heavy rainfall across Jamaica, the Cayman Islands, and the Yucatan Peninsula is likely to lead to flash and urban flooding. Mudslides are possible in Jamaica.

3. Tropical storm conditions are expected over portions of Jamaica for a few more hours, and over the Cayman Islands later tonight and Wednesday. Hurricane conditions are possible in the Cayman Islands by Wednesday morning. Tropical storm conditions are expected to spread westward from portions of the southern coast of Cuba in the warning area to, possibly, other portions of the southern coast of Cuba in the watch area tonight through Wednesday.

CHANGES WITH THIS ADVISORY: The government of Mexico has issued a Tropical Storm Warning along the north coast of the Yucatan Peninsula from Cabo Catoche westward to Dzilam. A Tropical Storm Watch has been issued for the north and west coasts of the Yucatan Peninsula from west of Dzilam to Campeche. The government of Cuba has discontinued the Tropical Storm Warning for the Cuban province of Santiago de Cuba. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Hurricane Warning is in effect for...
- Yucatan Peninsula of Mexico from Cancun to Punta Herrero, including Cozumel A Hurricane Watch is in effect for...
- Cayman Islands A Tropical Storm Warning is in effect for...
- Jamaica
- Southern coast of the Cuban provinces of Granma, Las Tunas, and Camaguey
- Cayman Islands
- Yucatan Peninsula of Mexico from north of Cancun to Dzilam
- Yucatan Peninsula of Mexico from south of Punta Herrero to Puerto Costa Maya A Tropical Storm Watch is in effect for...
- 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
- North and west coasts of the Yucatan Peninsula from west of Dzilam to Campeche A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. A warning is typically issued 36 hours before the anticipated first occurrence of tropical storm force winds, conditions that make outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion. A Hurricane Watch means that hurricane conditions are possible within the watch area. 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 the Yucatan Peninsula of Mexico should monitor the progress of Grace. Additional watches or warnings may be required early Wednesday. 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 expected to continue over portions of Jamaica for a few more hours. Tropical storm conditions are expected along a portion of the southern coast of Cuba within the warning area through tonight, and over the Cayman Islands beginning by early Wednesday. Hurricane conditions are possible in the Cayman Islands by early Wednesday. Tropical storm conditions are possible along the southern coast of Cuba within the watch area tonight and Wednesday. Hurricane conditions are expected within the warning area in the Yucatan Peninsula of Mexico on Wednesday night with tropical storm conditions beginning as early as Wednesday evening.

RAINFALL: The system is expected to produce the following rainfall amounts:

Over Jamaica, the Cayman Islands, and portions of the Yucatan Peninsula....3 to 6 inches of rain with isolated maximum totals of 10 inches are expected through Thursday. This heavy rainfall may lead to flash and urban flooding, and across Jamaica, mudslides will also be possible.

STORM SURGE: A storm surge could raise water levels as high as 1 to 3 ft above normal tide levels in portions of the Cayman Islands. A dangerous storm surge will raise water levels by as much as 3 to 5 ft above normal tide levels along the immediate coast near and to the north of where the center makes landfall in the northeastern Yucatan Peninsula late Wednesday or early Thursday. Near the coast, the surge will be accompanied by large and destructive waves.

SURF: Swells generated by Grace will spread westward from Jamaica to 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 1100 PM EDT (0300 UTC), the center of Tropical Storm Grace was located near latitude 18.4 North, longitude 79.2 West. Grace is moving toward the west near 14 mph (22 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 continue to move away from the western coast of Jamaica overnight. Grace is forecast to move near or over the Cayman Islands early Wednesday, and then approach the Yucatan peninsula of Mexico late Wednesday or early Thursday. Data from NOAA and Air Force Reserve reconnaissance aircraft indicate that maximum sustained winds are near 60 mph (95 km/h) with higher gusts. Grace is forecast to strengthen into a hurricane on Wednesday, with some additional strengthening possible prior to the center reaching the Yucatan Peninsula. Tropical storm force winds extend outward up to 115 miles (185 km) primarily to the east of the center. The latest minimum central pressure estimated from reconnaissance aircraft data is 1000 mb (29.53 inches).

NOAA and Air Force Hurricane Hunter aircraft that have been investigating Grace this evening have found that the center moved off the western tip of Jamaica shortly before 0000 UTC. Radar and conventional satellite imagery, as well as earlier microwave data, show that convective banding has increased with a band that wraps around the eastern and northern portions of the circulation. The Air Force reconnaissance aircraft measured a peak 850-mb flight-level wind of 64 kt, and both aircraft have measured believable SFMR winds of 50-52 kt. Based on those data the maximum winds were increased to 50 kt on the 0000 UTC intermediate advisory, and the initial intensity remains unchanged for this advisory.

Grace will be moving over the high ocean heat content waters of the northwestern Caribbean Sea during the next day or so. That, along with generally low to moderate vertical wind shear conditions, should allow for steady strengthening until Grace reaches the coast of the Yucatan Peninsula in just under 36 hours. The NHC intensity forecast call for Grace to become a hurricane on Wednesday, and the storm could peak near category 2 intensity before it reaches the coast of Mexico late Wednesday night or early Thursday. By the 36- hour forecast, some weakening is likely to have occurred as that point is now inland. Some weakening will likely occur while Grace moves over land, but restrengthening is predicted when the storm moves over the Bay of Campeche. The NHC intensity forecast is in best agreement with the HCCA and IVCN consensus aids.

Grace has been moving slightly north of due west, or 280/12 kt. A strong deep-layer ridge the extends from the western Atlantic across the eastern and central Gulf of Mexico should continue to steer the tropical storm westward to west-northwestward for the next several days. While the dynamical models agree on this overall forecast scenario, there remains some north-south spread with the HWRF, HMON, and GFS along the northern side of the guidance envelope, taking Grace near the northeastern portion of the Yucatan Peninsula. On the other hand, the UKMET and its ensemble mean depict a more westward track toward the southern portion of the Yucatan Peninsula of Mexico. The NHC forecast splits these differences and lies near the various consensus aids, which were just a tad farther south this cycle.