ZCZC MIATCDAT5 ALLTTAA00 KNHC DDHHMMPotential Tropical Cyclone Fifteen Discussion Number 1NWS National Hurricane Center Miami FL AL1520171100 AM AST Sat Sep 16 2017Satellite images indicate that the area of low pressure locatedseveral hundred miles east of the Lesser Antilles has become betterorganized with curved banding features now better established.Since there is still no indication of a well-defined center andbecause tropical storm watches have been issued for portions ofthe Leeward Islands, NHC has initiated advisories on this system asa potential tropical cyclone. The initial wind speed is estimatedto be 30 kt based on a blend of the Dvorak classifications from TAFBand SAB.FORECAST POSITIONS AND MAX WINDSINIT 16/1500Z 12.2N 50.5W 30 KT 35 MPH...POTENTIAL TROP CYCLONE 12H 17/0000Z 12.8N 52.8W 35 KT 40 MPH...TROPICAL STORM 24H 17/1200Z 13.6N 55.1W 40 KT 45 MPH 36H 18/0000Z 14.3N 56.9W 50 KT 60 MPH 48H 18/1200Z 15.0N 58.6W 60 KT 70 MPH 72H 19/1200Z 16.3N 61.3W 75 KT 85 MPH 96H 20/1200Z 17.6N 64.0W 80 KT 90 MPH120H 21/1200Z 18.7N 67.3W 80 KT 90 MPH$$Forecaster CangialosiNNNN
000WTNT45 KNHC 162038TCDAT5Tropical Storm Maria Discussion Number 2NWS National Hurricane Center Miami FL AL152017500 PM AST Sat Sep 16 2017Satellite images indicate that the system located several hundredmiles east of the Lesser Antilles has become much better organizedthroughout the day. The low-level center of circulation is nowwell defined, and banding features have become better established inall quadrants. The initial wind speed is increased to 45 kt, inagreement with a Dvorak classification from TAFB. This makes thesystem a tropical storm, Maria becomes the thirteenth named stormin the Atlantic basin this season.Maria is moving quickly westward at 17 kt on the south side of amid-level ridge. This ridge is expected to remain in place butweaken some, which should cause Maria to move west-northwestward ata progressively slower pace through the forecast period. Themodels are in fair agreement, and the NHC official track forecastis closest to the HCCA model. This forecast takes the core ofMaria near the Leeward Islands in 48 to 72 hours, and close to theVirgin Islands and Puerto Rico in about 4 days.The tropical storm is located within conducive environmentalconditions of low wind shear, high amounts of moisture, and overwarm 29 deg C SSTs. Since these conditions are not expected tochange much, steady or even rapid strengthening is likely during thenext 3 to 4 days. Slight weakening is predicted by the end of theforecast period due to some land interaction and a slight increasein wind shear. The NHC intensity forecast is raised significantlyfrom the previous one to come into better agreement with the latestguidance.KEY MESSAGES:1. Maria is expected to strengthen and affect portions of theLeeward Islands as a hurricane early next week, bringing dangerouswind, storm surge and rainfall hazards. Hurricane and tropicalstorm 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 andPuerto Rico by mid week as a dangerous major hurricane, andhurricane watches could be issued for these islands as early asSunday. Interests in these areas should monitor the progress ofMaria and follow any advice given by local officials.FORECAST POSITIONS AND MAX WINDSINIT 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 MPH120H 21/1800Z 19.5N 68.6W 95 KT 110 MPH$$Forecaster Cangialosi