ZCZC MIATCDAT3 ALL TTAA00 KNHC DDHHMM Tropical Storm Rina Discussion Number 1 NWS National Hurricane Center Miami FL AL182023 1100 AM AST Thu Sep 28 2023 Visible imagery early this morning indicates that a well-defined center has emerged to the northwest of persistent deep convective activity. A recent ASCAT pass and subjective Dvorak estimates from TAFB both indicate that the system has become a tropical cyclone. Thus, advisories have been initiated on Tropical Storm Rina. The recent partial ASCAT pass indicated winds in the 30-35 kt range but did not capture the most intense convection east of the center. Therefore, the current intensity for this advisory is set at 35 kt. Moderate deep-layer westerly shear is likely to limit intensification in the short term, and this shear is expected to increase this weekend and early next week. Persistent shear, in addition to the close proximity and uncertain interaction with Tropical Storm Philippe, should limit intensification during the forecast period. The NHC forecast is in the middle of the guidance envelope and very close to the HCCA solution. Rina is expected to remain a tropical storm throughout the forecast period, though some of the regional hurricane models do indicate a faster rate of intensification during the next several days compared to the NHC forecast. Rina is moving north-northwestward, with an initial forward speed near 9 kt. The tropical storm should begin to turn more westward today and continue this general motion for the next several days. Early next week, the system is expected to turn northward as a mid-level ridge builds to the west. The NHC forecast is a blend of the HCCA and TVCN consensus guidance throughout the forecast period. Confidence in the track forecast is lower than normal based on the model spread and uncertainty regarding the potential interaction with Tropical Storm Philippe during the next several days. FORECAST POSITIONS AND MAX WINDS INIT 28/1500Z 17.4N 45.0W 35 KT 40 MPH 12H 29/0000Z 18.5N 45.8W 35 KT 40 MPH 24H 29/1200Z 19.2N 46.8W 40 KT 45 MPH 36H 30/0000Z 19.6N 47.8W 45 KT 50 MPH 48H 30/1200Z 19.9N 49.0W 50 KT 60 MPH 60H 01/0000Z 20.4N 50.4W 50 KT 60 MPH 72H 01/1200Z 21.1N 52.2W 45 KT 50 MPH 96H 02/1200Z 23.9N 56.2W 40 KT 45 MPH 120H 03/1200Z 26.2N 58.2W 40 KT 45 MPH $$ Forecaster Hogsett/Cangialosi NNNN