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Tropical Storm Joyce Forecast Discussion Number 6
2018-09-14 04:38:22| National Hurricane Center (Atlantic)
Issued at 1100 PM AST Thu Sep 13 2018 466 WTNT45 KNHC 140238 TCDAT5 Tropical Storm Joyce Discussion Number 6 NWS National Hurricane Center Miami FL AL102018 1100 PM AST Thu Sep 13 2018 Beginning around 6 hours ago, convection redeveloped near the center of Joyce. Since then, the cyclone has become displaced from the upper-level low, and an ASCAT overpass around 2330 UTC showed that Joyce has a small radius of maximum winds of around 30 n mi. Based on these factors, it appears Joyce has become a tropical cyclone. The ASCAT pass showed maximum winds of just over 30 kt, but its possible the instrument slightly under-sampled the maximum winds of the small cyclone. In addition, convection near the center increased somewhat after the time of the ASCAT pass. The initial intensity has therefore been held at 35 kt, making Joyce a tropical storm. Joyce has accelerated a little toward the west-southwest, perhaps more than previously anticipated. As a result, the forecast has been shifted south at most forecast hours, but not quite as far as the consensus models would suggest. There is otherwise no change to the track forecast reasoning, and Joyce is still expected to move slowly generally southward while Helene passes to the east until accelerating toward the northeast ahead of a mid-latitude trough in a day or two. Despite the recent, and perhaps temporary, resurgence of convection, no change has been made to the intensity forecast. None of the guidance shows much intensification, and the NHC forecast continues to rely on a blend of the intensity consensus and the GFS and ECMWF, which only show gradual weakening throughout the forecast period. Considering that the cyclone has only gradually weakened to this point, this still seems like a reasonable forecast. FORECAST POSITIONS AND MAX WINDS INIT 14/0300Z 32.9N 44.4W 35 KT 40 MPH 12H 14/1200Z 32.2N 44.7W 35 KT 40 MPH 24H 15/0000Z 31.7N 44.2W 35 KT 40 MPH 36H 15/1200Z 32.2N 43.3W 35 KT 40 MPH 48H 16/0000Z 33.3N 42.1W 30 KT 35 MPH 72H 17/0000Z 36.0N 37.5W 30 KT 35 MPH 96H 18/0000Z...DISSIPATED $$ Forecaster Zelinsky
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