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#939750 (Received by flhurricane at: 5:24 PM 12.Sep.2018) TCDAT5 Subtropical Storm Joyce Discussion Number 1 NWS National Hurricane Center Miami FL AL102018 500 PM AST Wed Sep 12 2018 The strong low pressure system which the NHC has been monitoring in the north Atlantic for a couple of days has developed a cyclonically curved band of deep convection near the center, and scatterometer data indicate that the winds are near 40 kt. Since the system is still vertically stacked with an upper-low, it is then classified as a subtropical cyclone at this time. However, the cyclone is gaining organization while it is acquiring tropical characteristics. The NHC forecast calls for Joyce to transform into a tropical system in about 12 to 24 hours. Since the ocean is warm, some slight strengthening is possible during the next 3 days. After that time, Joyce will be over cooler waters and should then be absorbed by a larger extratropical low. Joyce has been moving southwestward or 225 degrees at 5 kt, steered by the northerly flow around the subtropical high which has been steering Florence and to west of the mid-latitude trough which is forcing Helene to recurve. In a couple of days, global models indicate that the steering pattern will change as the trough amplifies, and Joyce should then turn toward the northeast with an increase in forward speed. FORECAST POSITIONS AND MAX WINDS INIT 12/2100Z 34.3N 41.9W 40 KT 45 MPH 12H 13/0600Z 33.7N 42.6W 40 KT 45 MPH...TROPICAL STORM 24H 13/1800Z 33.0N 43.5W 40 KT 45 MPH 36H 14/0600Z 32.5N 43.5W 45 KT 50 MPH 48H 14/1800Z 32.5N 43.5W 50 KT 60 MPH 72H 15/1800Z 34.0N 41.0W 50 KT 60 MPH 96H 16/1800Z 37.0N 35.0W 40 KT 45 MPH 120H 17/1800Z...ABSORBED $$ Forecaster Avila |