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 tonight.

2. Over the next few days, heavy rainfall across the Cayman Islands as well as portions of the Yucatan Peninsula and Vera Cruz State should lead to flash and urban flooding. Mudslides will be possible in Jamaica.

3. Tropical storm conditions are expected over the Cayman Islands through this morning. Hurricane conditions are possible in the Cayman Islands later this 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 today.

CHANGES WITH THIS ADVISORY: None. 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...
- 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 tropicalstorm 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 later this morning.

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, and hurricane conditions are possible, over the Cayman Islands through this morning. 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, with tropical storm conditions beginning as early as this evening.

RAINFALL: Grace is expected to produce the following rainfall amounts:

Over Jamaica, the Cayman Islands, portions of the Yucatan Peninsula and Vera Cruz state....4 to 8 inches of rain 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 Jamaica.

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 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 to the Cayman Islands, the southern coast of Cuba, and the Yucatan Peninsula of Mexico. These swells are likely to cause lifethreatening surf and rip current conditions. Please consult products from your local weather office.

At 800 AM EDT (1200 UTC), the center of Tropical Storm Grace was located by an Air Force Reserve Hurricane Hunter aircraft near latitude 18.8 North, longitude 80.9 West. Grace is moving toward the westnorthwest near 16 mph (26 km/h). A general westward to westnorthwestward motion is expected for the next several days. On the forecast track, the center of Grace will continue to move near or the Cayman Islands later this morning. Grace is expected to make landfall in the Yucatan peninsula of Mexico early Thursday, and move into the southwest Gulf of Mexico early Friday.

Maximum sustained winds are near 65 mph (100 km/h) with higher gusts. Grace is forecast to strengthen into a hurricane later today, with some additional strengthening possible prior to the center reaching the eastern Yucatan Peninsula.

Tropicalstormforce winds extend outward up to 115 miles (185 km) from the center. Wind gusts to hurricane force have been reported on Grand Cayman.

The minimum central pressure estimated from Air Force Hurricane Hunter observations is 993 mb (29.32 inches).

An Air Force Reserve reconnaissance aircraft investigating Grace earlier this morning observed a peak 850-mb flight-level wind of 61 kt in the northeastern quadrant along with reliable SFMR surface wind speeds of 50-52 kt. The aircraft measured a central pressure of about 1000 mb, a reading that had been steady for about 3 hours. Those data were the basis for maintaining the 0600 UTC intensity at 50 kt. Since the last recon mission, however, deep convection has increased markedly over the low-level center, with cloud tops exceeding -75 deg C. Although the center is just inside the western edge of convective cloud canopy due to modest west-northwesterly vertical wind shear, Dvorak satellite intensity estimates from TAFB and SAB are a consensus T3.5/55 kt. These intensity estimates, along with the increase in convection over the center is the justification for increasing the 0900 UTC advisory intensity to 55 kt.

Grace has been maintaining a steady course north of due west, or 280/14 kt for more than 18 hours. A strong deep-layer ridge to the north of the cyclone is expected to keep Grace moving in direction between west and west-northwest through the 96-hour forecast period. The latest NHC model guidance remain in strong agreement on Grace making landfall along the northeastern coast of the Yucatan Peninsula of Mexico shortly after the 24-hour forecast period, followed by a motion across the peninsula and emerging over the Bay of Campeche around 36 hours. Thereafter, the model guidance begins to diverge, with the HWRF, HMON, and COAMPS-TC regional models along the northern side of the guidance envelope, the GFS and UKMET global models down the middle, and the ECMWF model along the southern edge of the guidance suite. The new NHC forecast lies close to the previous advisory track and the consensus models TVCA and HCCA, which are a little south of the FSSE consensus model.

Although the upper-level wind environment isn't ideal for rapid strengthening, it is conducive enough for steady strengthening to occur due to the flow forecast to be strongly diffluent. Sea-surface temperatures are expected to be near 30 deg C and the water is also deep and warm, which should prevent any cold upwelling from occurring beneath the cyclone. As a result, a peak intensity of 75 kt just prior to landfall has been carried over from the previous advisory, which is a little above all of the 0600 UTC intensity guidance. Although Grace will weaken substantially after passing over the Yucatan peninsula, restrengthening is expected over the warm waters of thew Bay of Campeche in the 48-72- hour period where the upper-level flow regime is forecast to be more conducive for intensification. Dissipation is now expected over the mountains of central Mexico by 120 hours. The NHC intensity forecast is in best agreement with the HCCA and IVCN consensus aids at 36 hours and beyond.