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| #1152959 (Received by flhurricane at: 4:44 PM 15.Sep.2023) TCDAT5 Tropical Depression Fifteen Discussion Number 2 NWS National Hurricane Center Miami FL AL152023 500 PM AST Fri Sep 15 2023 The depression has lost some convective organization since this morning, but the low-level circulation appears to be better defined in recent visible satellite imagery. There are a couple of bursts of convection just north of the center, but there is a lack of overall banding at this time. The initial intensity is held at 30 kt, which is in agreement with the latest Dvorak Data T-number from TAFB. The center appears to have reformed to the north since this morning, which had lead to a rather uncertain initial motion estimate of 320/11 kt. The global model guidance suggests that there could be some additional center reformations during the next 12-24 hours until an inner-core becomes better established. The early portion of the track forecast was shifted northward, based on the farther north initial position. A deep-layer ridge over the central Atlantic is expected to steer the system northwestward during the next several days. By day 4, a mid-latitude trough moving over the western Atlantic should allow the cyclone to turn north-northwestward near the end of the period. The 12Z dynamical model guidance made a noticeable eastward shift, and the NHC forecast has been adjusted in that direction. The updated track forecast is close to the consensus aids through 72 hours, but is along the left side of the model envelope at days 4 and 5. The depression is likely to only gradually intensify during the next 12 hours or so as it is still in the formative stage and lacks inner-core structure. After that time, a faster rate of intensification is indicated in the official forecast while the system remains in an environment of low vertical wind shear and it traverses warm sea surface temperatures. The intensity guidance is somewhat lower this cycle, but the NHC forecast remains generally the same as before. This is near the upper-end of the latest guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 15/2100Z 15.4N 44.0W 30 KT 35 MPH 12H 16/0600Z 16.7N 45.0W 30 KT 35 MPH 24H 16/1800Z 18.5N 46.6W 40 KT 45 MPH 36H 17/0600Z 20.4N 48.4W 50 KT 60 MPH 48H 17/1800Z 22.0N 50.1W 60 KT 70 MPH 60H 18/0600Z 23.6N 51.7W 70 KT 80 MPH 72H 18/1800Z 25.1N 53.6W 85 KT 100 MPH 96H 19/1800Z 28.0N 57.3W 100 KT 115 MPH 120H 20/1800Z 32.0N 59.0W 100 KT 115 MPH $$ Forecaster Brown |
