1. Hurricane conditions and a dangerous storm surge are expected in portions of the Hurricane Warning area in the eastern Yucatan Peninsula of Mexico beginning late tonight or early Thursday. Preparations to protect life and property should be rushed to completion.

2. There is an increasing risk of hurricane conditions and dangerous storm surge in portions of eastern mainland Mexico beginning late Friday, and a Hurricane Watch will likely be issued for part of this area later today.

3. Over the next few days, heavy rainfall across the Cayman Islands as well as portions of the Yucatan Peninsula and Veracruz State should lead to flash and urban flooding, with mudslides possible in the Mexican state of Veracruz.

CHANGES WITH THIS ADVISORY: The Hurricane Watch is discontinued for the Cayman Islands. 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 Tropical Storm Warning is in effect for...
- Cayman Islands
- Yucatan Peninsula of Mexico from north of Cancun to Campeche
- Yucatan Peninsula of Mexico from south of Punta Herrero to Puerto Costa Maya A Tropical Storm Watch is in effect for...
- Southern coast Cuban province of Pinar del Rio, as well as Isla de la Juventud 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 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 eastern mainland Mexico should monitor the progress of Grace. 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 over portions of the Cayman Islands for the next few hours. Tropical storm conditions are possible along the southern coast of Cuba within the watch area through today. Hurricane conditions are expected within the warning area in the Yucatan Peninsula of Mexico late tonight or early Thursday, with tropical storm conditions beginning as early as this evening.

RAINFALL: Grace is expected to produce the following rainfall amounts: Over the Cayman Islands, portions of the Yucatan Peninsula and Veracruz State of Mexico....4 to 8 inches with isolated maximum totals of 12 inches are expected through Friday night. This heavy rainfall could lead to flash and urban flooding, with mudslides possible in Veracruz.

STORM SURGE: 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 tonight 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 and the Cayman Islands to 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 AM EDT (1500 UTC), the center of Hurricane Grace was located by Air Force Reserve and NOAA Hurricane Hunter aircraft near latitude 19.4 North, longitude 82.2 West. Grace is moving toward the west northwest near 15 mph (24 km/h). A general west northwestward to westward motion is expected for the next several days. On the forecast track, the center of Grace will continue to move away from Grand Cayman today. Grace is expected to make landfall in the Yucatan Peninsula Thursday morning, and move over the southwest Gulf of Mexico early Friday.

Aircraft data indicate that maximum sustained winds are near 75 mph (120 km/h) with higher gusts. Some additional strengthening is forecast before the center of Grace reaches the eastern Yucatan Peninsula. Weakening will occur while the center moves over the Yucatan Peninsula on Thursday, with restrengthening expected when Grace moves over the southwest Gulf of Mexico on Friday. Hurricane force winds extend outward up to 25 miles (35 km) from the center and tropical storm force winds extend outward up to 115 miles (185 km). The estimated minimum central pressure is 992 mb (29.30 inches).

Grace is becoming better organized on satellite images with a comma-shaped cloud pattern, and the upper-level outflow remains well defined. Wind gusts well into the hurricane-force range were measured on Grand Cayman earlier this morning, along with some damage on the island. Recent flight-level and SFMR observations from both the Air Force and NOAA Hurricane Hunter aircraft support sustained 65-kt surface winds, so the system is being upgraded to a hurricane on this advisory.

Although Grace is situated over waters of very high oceanic heat content, moderate northwesterly shear and only marginally moist mid-level air could slightly impede intensification. However, some additional strengthening is expected before landfall tonight or early Thursday. Weakening will occur due to Grace's passage over Yucatan, although that land mass has relatively low terrain. Reintensification is anticipated over the Bay of Campeche on Friday, and the system should regain hurricane strength before reaching the east coast of mainland Mexico. The official intensity forecast is similar to the numerical model consensus.

Grace has been moving west-northwestward near 13 kt. A prominent mid-tropospheric ridge is likely to remain in place to the north of the cyclone for the next several days. This pattern should keep steering Grace on a west-northwestward to westward track for 72-96 hours. The track guidance models are in excellent agreement and little change has been made to the NHC track forecast compared to the previous few packages.

A Hurricane Watch will likely be required for a portion of the coast of eastern mainland Mexico later today.