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| #939974 (Received by flhurricane at: 4:57 PM 13.Sep.2018) TCDAT5 Subtropical Storm Joyce Discussion Number 5 NWS National Hurricane Center Miami FL AL102018 500 PM AST Thu Sep 13 2018 Joyce has an exposed center this afternoon with no substantial deep convection anywhere nearby. The initial intensity remains 35 kt, consistent with the Hebert-Poteat ST2.5 classification from TAFB as well as the appearance of the very tight low-level center as seen in the GOES-16 visible satellite imagery. As Joyce still remains embedded within an upper-level trough, the system retains the subtropical storm label. Joyce has now been devoid of deep convection for almost a day, due to the dry stable air combined with strong tropospheric vertical shear. As the system is not expected to undergo extratropical transition, without deep convection gradual weakening is anticipated until dissipation in about four days. The official intensity forecast is a blend of the IVCN intensity consensus scheme along with the GFS and ECMWF global model guidance. This new forecast indicates a reduction from the previous advisory, and in fact, Joyce could become a post-tropical cyclone soon if deep convection does not reappear shortly. Joyce is moving toward the southwest at about 5 kt, as it is situated slightly to the west of an upper-level low. In a couple days, a new short wave trough will dive equatorward west of Joyce and begin advecting Joyce toward the northeast. The new NHC track forecast is a bit to the left (southwest) of the previous advisory and is based upon a blend of the HWRF hurricane model and the GFS and ECMWF global models. FORECAST POSITIONS AND MAX WINDS INIT 13/2100Z 33.6N 44.2W 35 KT 40 MPH 12H 14/0600Z 33.1N 44.6W 35 KT 40 MPH 24H 14/1800Z 32.3N 44.7W 35 KT 40 MPH 36H 15/0600Z 32.4N 44.0W 35 KT 40 MPH 48H 15/1800Z 33.2N 43.1W 30 KT 35 MPH 72H 16/1800Z 36.0N 39.5W 25 KT 30 MPH 96H 17/1800Z...DISSIPATED $$ Forecaster Landsea |
