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| #938017 (Received by flhurricane at: 10:50 AM 01.Sep.2018) TCDAT1 Tropical Storm Florence Discussion Number 9 NWS National Hurricane Center Miami FL AL062018 1100 AM AST Sat Sep 01 2018 Satellite images indicate that Florence`s cloud pattern has improved in organization with the low-level center embedded within the convection, and a cyclonically curved band surrounding the system. A blend of subjective and objective Dvorak numbers from TAFB, SAB, and the UW-CIMMS yield an initial intensity of 40 kt. My predecessor wrote a very clear explanation of the reasoning of his track and intensity forecasts, and I do not think I can improve on it. The environment continues to be mixed with favorable and unfavorable conditions for Florence to strengthen. Currently, the shear is low and favors strengthening, but the ocean along the cyclone`s forecast path is cooler. The latter condition should inhibit significant intensification. After 3 days, the opposite is anticipated -- the ocean will be warmer, but the shear will likely be high. Only at the very long range could both factors become favorable. The best option at this time is to show only a gradual strengthening at the rate indicated by the intensity consensus aids. Florence is still moving toward the west-northwest or 295 degrees at 12 kt. No change in track is anticipated during the next 3 days while Florence is located to the south of the subtropical ridge. After that time, Florence will reach a break in the ridge causing the cyclone to turn toward the northwest with a decrease in forward speed. The confidence in the forecast is high during the next 3 days when the track guidance envelope is tightly packed. Thereafter, the confidence is not so high since the envelope widens and becomes bounded by the easternmost HWRF and the westernmost ECMWF models. Since the guidance envelope shifted a little bit westward, the NHC forecast was also adjusted slightly in that direction, primarily during the end of the forecast period. FORECAST POSITIONS AND MAX WINDS INIT 01/1500Z 14.8N 27.8W 40 KT 45 MPH 12H 02/0000Z 15.3N 29.7W 45 KT 50 MPH 24H 02/1200Z 16.1N 32.4W 50 KT 60 MPH 36H 03/0000Z 16.5N 35.0W 50 KT 60 MPH 48H 03/1200Z 17.0N 37.5W 55 KT 65 MPH 72H 04/1200Z 19.0N 42.5W 60 KT 70 MPH 96H 05/1200Z 21.0N 46.5W 60 KT 70 MPH 120H 06/1200Z 23.5N 50.0W 55 KT 65 MPH $$ Forecaster Avila |
