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| #1153006 (Received by flhurricane at: 10:54 PM 15.Sep.2023) TCDAT5 Tropical Depression Fifteen Discussion Number 3 NWS National Hurricane Center Miami FL AL152023 1100 PM AST Fri Sep 15 2023 Deep convection has increased over the northern portion of the depression`s broad circulation this evening, however it is still not particularly well organized. A recent ASCAT passed indicated that the circulation is still broad and that the center may be trying to reform farther north closer to the convection. The scatterometer data revealed peak winds of 25-30 kt, and the initial wind speed is maintained at 30 kt for this advisory. The initial motion is a still somewhat uncertain 320/12 kt. A deep-layer ridge over the central Atlantic should steer the depression northwestward through early next week. By late Tuesday, a mid-latitude trough moving westward over the western Atlantic is expected to cause the cyclone to turn north- northwestward and northward near the end of the forecast period. The track guidance is in relatively good agreement on this scenario, and the latest NHC track forecast lies near the middle of the guidance envelope. Given the current structure of the system, only gradual strengthening is likely overnight. Once an inner core become established a faster rate of strengthening seems likely as the system traverses warm waters and remains in a low vertical wind shear conditions. Steady to potentially rapid strengthening is predicted later this weekend, and the system is forecast to become a hurricane by late Sunday or Monday. The NHC intensity forecast is near the higher-end of the guidance, close to the HCCA model through 72 hours, and is then near the higher dynamical guidance at 96 h. By late in the period, increasing southwesterly vertical wind shear is likely to cause some gradual weakening. FORECAST POSITIONS AND MAX WINDS INIT 16/0300Z 16.3N 44.7W 30 KT 35 MPH 12H 16/1200Z 17.9N 45.8W 35 KT 40 MPH 24H 17/0000Z 20.1N 47.7W 45 KT 50 MPH 36H 17/1200Z 21.7N 49.4W 55 KT 65 MPH 48H 18/0000Z 23.3N 50.9W 70 KT 80 MPH 60H 18/1200Z 24.7N 52.6W 80 KT 90 MPH 72H 19/0000Z 26.0N 54.6W 90 KT 105 MPH 96H 20/0000Z 29.3N 57.9W 100 KT 115 MPH 120H 21/0000Z 34.1N 58.3W 90 KT 105 MPH $$ Forecaster Brown |
