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| #1057566 (Received by flhurricane at: 4:54 PM 18.Aug.2021) TCDAT2 Hurricane Grace Discussion Number 22 NWS National Hurricane Center Miami FL AL072021 500 PM EDT Wed Aug 18 2021 A ragged eye appeared for a while on visible satellite imagery, but it has recently been obscured by cumulonimbus tops. The overall cloud pattern has been maintaining its organization with some convective banding features and very cold cloud tops, mainly over the eastern portion of the circulation. The current intensity estimate is set at 70 kt, which is a blend of Dvorak estimates from TAFB and SAB. Another Air Force Reserve Hurricane Hunter aircraft is scheduled to investigate the hurricane in a few hours to provide another intensity estimate. Grace will continue to move over waters of very high oceanic heat content prior to reaching the east coast of the Yucatan Peninsula, which of course favors intensification. Aside from moderate northwesterly shear, a possible impediment to strengthening is a northeast to southwest-oriented shear axis located just to the northwest of the hurricane. Nonetheless, some intensification is anticipated before landfall in Yucatan, with restrengthening over the Bay of Campeche. The official intensity forecast continues to be in general agreement with the multi-model consensus predictions, IVCN and HCCA. Grace is moving west-northwestward, or about 285/14 kt. There has been essentially no change to the track forecast philosophy. Grace should maintain a west-northwestward to westward motion, on the southern periphery of a strong subtropical ridge, for the next several days. The official track forecast is very similar to the previous one and about on top of the latest multi-model consensus, TVCA. A Hurricane Watch will likely be required for a portion of the coast of eastern mainland Mexico tonight. Key Messages: 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 tonight. 3. Through the weekend, heavy rainfall across the Cayman Islands as well as portions of the Yucatan Peninsula and Veracruz State should lead to flash and urban flooding. In addition, the heavy rainfall from Grace will be capable of producing mudslides in Veracruz. FORECAST POSITIONS AND MAX WINDS INIT 18/2100Z 19.7N 83.7W 70 KT 80 MPH 12H 19/0600Z 20.2N 86.1W 75 KT 85 MPH 24H 19/1800Z 20.7N 89.3W 55 KT 65 MPH...INLAND 36H 20/0600Z 20.9N 92.2W 60 KT 70 MPH...OVER WATER 48H 20/1800Z 20.8N 94.6W 70 KT 80 MPH...OVER WATER 60H 21/0600Z 20.4N 97.3W 75 KT 85 MPH...INLAND 72H 21/1800Z 20.0N 99.9W 30 KT 35 MPH...INLAND 96H 22/1800Z 19.5N 104.0W 20 KT 25 MPH...POST-TROP/INLAND 120H 23/1800Z...DISSIPATED $$ Forecaster Pasch |