000 WTNT45 KNHC 211448 TCDAT5 Hurricane Maria Discussion Number 22 NWS National Hurricane Center Miami FL AL152017 1100 AM AST Thu Sep 21 2017 Maria is maintaining a large, 40 nm wide eye, and overall, the hurricane's satellite presentation has not changed since the previous advisory. An Air Force Reserve Hurricane Hunter aircraft investigating the system has not measured flight-level winds as high as last evening's mission, and the central pressure has remained relatively steady. Although there were higher SFMR winds measured, especially to the northeast of the center, the flight meteorologist reported that the instrument appears to be running 5-10 kt too high. Therefore, the initial intensity is held at 100 kt. Maria appears to be moving over the remnant cold wake leftover from Hurricane Irma, but it should begin to move over an area of higher oceanic heat content during the next 24 hours or so. Therefore, some strengthening is still forecast, although it is not especially aggressive given what the latest intensity guidance is showing. Gradual weakening is likely from 48 hours onward due to some increase in southwesterly shear, as well as lower oceanic heat content over the western Atlantic. Still, Maria is expected to remain a hurricane for the next 5 days. The initial motion is northwestward, or 310/8 kt. Maria will be moving between a mid-level high centered south of Bermuda and a broad trough extending from Tropical Storm Jose southwestward into the northern Gulf of Mexico. As a result, Maria is expected to turn gradually north-northwestward to north-northeastward by the end of the forecast period, keeping it over the waters of the western Atlantic after moving by the Turks and Caicos Islands and the southeastern Bahamas. The track models continue to be tightly clustered, and the updated NHC track forecast lies right along the previous forecast, down the middle of the guidance envelope. KEY MESSAGES: 1. Flash flood emergencies continue in portions of Puerto Rico due to persistent heavy rainfall from Maria's trailing rainbands. Catastrophic flooding is occurring on the island, especially in areas of mountainous terrain, and everyone in Puerto Rico should continue to follow advice from local officials to avoid these life-threatening flooding conditions. 2. A Hurricane Warning is in effect for the northern coast of the Dominican Republic, the Turks and Caicos Islands, and the southeastern Bahamas, where Maria is expected to bring dangerous wind, storm surge, and heavy rainfall. FORECAST POSITIONS AND MAX WINDS INIT 21/1500Z 20.2N 69.1W 100 KT 115 MPH 12H 22/0000Z 21.0N 69.9W 105 KT 120 MPH 24H 22/1200Z 22.2N 70.7W 105 KT 120 MPH 36H 23/0000Z 23.6N 71.4W 100 KT 115 MPH 48H 23/1200Z 25.1N 71.9W 95 KT 110 MPH 72H 24/1200Z 28.2N 72.3W 95 KT 110 MPH 96H 25/1200Z 30.5N 71.5W 85 KT 100 MPH 120H 26/1200Z 33.0N 70.0W 75 KT 85 MPH $$ Forecaster Berg