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| #1067905 (Received by flhurricane at: 10:42 PM 30.Oct.2021) TCDAT1 Subtropical Storm Wanda Discussion Number 1 NWS National Hurricane Center Miami FL AL212021 1100 PM AST Sat Oct 30 2021 The non-tropical low that NHC has been monitoring for subtropical transition over the central Atlantic appears to have completed the process this evening. Satellite images indicate that there are no longer fronts attached to the low, and showers and thunderstorms have become concentrated near the center. The low has some tropical characteristics (small radius of maximum wind and concentrated convection) and some subtropical characteristics (co-located with an upper-level trough and nearby fronts). The system is designated as a subtropical storm for now since there appears to be more support for that status. The initial intensity is estimated to be 45 kt based on recent ASCAT data, which makes the cyclone Subtropical Storm Wanda. The storm has been moving east-southeastward at 18 kt. A slower east-southeast to southeast motion is expected during the next day or so as Wanda moves with the deep-layer trough that it is embedded within. After that time, the trough is expected to cut off, and Wanda will likely meander on Monday before turning sharply northward or northeastward by the middle of next week when the system moves in the flow between the low and a building ridge. Most of the models agree on the general evolution, but there are notable speed differences. The NHC track forecast lies near the various consensus aids. Wanda will likely maintain its strength during the next several days. Although the system will remain over relatively cool waters of about 23-24 C during the next couple of days, cold air aloft should aid in the continued development of deep convection and could allow the system to strengthen slightly during that time period. Beyond that time, Wanda should begin to move over cooler waters and that will likely end its opportunity to gain strength and lead to post-tropical transition by the end of the forecast period. The models are in good agreement on keeping Wanda steady state, and the NHC intensity forecast lies near the middle of the guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 31/0300Z 36.2N 45.4W 45 KT 50 MPH 12H 31/1200Z 35.8N 43.9W 45 KT 50 MPH 24H 01/0000Z 35.3N 43.6W 50 KT 60 MPH 36H 01/1200Z 34.3N 43.2W 50 KT 60 MPH 48H 02/0000Z 33.8N 42.1W 45 KT 50 MPH 60H 02/1200Z 34.5N 40.9W 45 KT 50 MPH 72H 03/0000Z 36.4N 39.9W 45 KT 50 MPH 96H 04/0000Z 41.4N 39.6W 45 KT 50 MPH 120H 05/0000Z 46.2N 35.4W 45 KT 50 MPH...POST-TROPICAL $$ Forecaster Cangialosi |