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#903357 (Received by flhurricane at: 4:41 PM 16.Sep.2017) TCDAT5 Tropical Storm Maria Discussion Number 2 NWS National Hurricane Center Miami FL AL152017 500 PM AST Sat Sep 16 2017 Satellite images indicate that the system located several hundred miles east of the Lesser Antilles has become much better organized throughout the day. The low-level center of circulation is now well defined, and banding features have become better established in all quadrants. The initial wind speed is increased to 45 kt, in agreement with a Dvorak classification from TAFB. This makes the system a tropical storm, Maria becomes the thirteenth named storm in the Atlantic basin this season. Maria is moving quickly westward at 17 kt on the south side of a mid-level ridge. This ridge is expected to remain in place but weaken some, which should cause Maria to move west-northwestward at a progressively slower pace through the forecast period. The models are in fair agreement, and the NHC official track forecast is closest to the HCCA model. This forecast takes the core of Maria near the Leeward Islands in 48 to 72 hours, and close to the Virgin Islands and Puerto Rico in about 4 days. The tropical storm is located within conducive environmental conditions of low wind shear, high amounts of moisture, and over warm 29 deg C SSTs. Since these conditions are not expected to change much, steady or even rapid strengthening is likely during the next 3 to 4 days. Slight weakening is predicted by the end of the forecast period due to some land interaction and a slight increase in wind shear. The NHC intensity forecast is raised significantly from the previous one to come into better agreement with the latest guidance. KEY MESSAGES: 1. Maria is expected to strengthen and affect portions of the Leeward Islands as a hurricane early next week, bringing dangerous wind, storm surge and rainfall hazards. Hurricane and tropical storm watches have been issued for portions of the Lesser Antilles, and additional watches will likely be issued tonight and Sunday. 2. Maria could also affect the British and U.S. Virgin Islands and Puerto Rico by mid week as a dangerous major hurricane, and hurricane watches could be issued for these islands as early as Sunday. Interests in these areas should monitor the progress of Maria and follow any advice given by local officials. FORECAST POSITIONS AND MAX WINDS INIT 16/2100Z 12.3N 52.6W 45 KT 50 MPH 12H 17/0600Z 13.0N 54.5W 55 KT 65 MPH 24H 17/1800Z 13.9N 56.6W 65 KT 75 MPH 36H 18/0600Z 14.6N 58.3W 70 KT 80 MPH 48H 18/1800Z 15.2N 59.8W 80 KT 90 MPH 72H 19/1800Z 16.5N 62.7W 95 KT 110 MPH 96H 20/1800Z 17.9N 65.5W 105 KT 120 MPH 120H 21/1800Z 19.5N 68.6W 95 KT 110 MPH $$ Forecaster Cangialosi |