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| #1068229 (Received by flhurricane at: 10:42 AM 02.Nov.2021) TCDAT1 Tropical Storm Wanda Discussion Number 11 NWS National Hurricane Center Miami FL AL212021 300 PM GMT Tue Nov 02 2021 After the overnight burst of deep convection and associated improved organization, dry air has wrapped into the system from all quadrants and has temporarily eroded Wanda`s inner-core convection. Despite the recent convective degradation, visible satellite imagery indicates that the cyclone`s low-level circulation has improved, with well-defined, curved low-level cloud lines and shallow convection having become more evident. Based on improved low-level structure, the intensity estimate remains at 45 kt despite the overall loss of deep convection. During the past 6 h, Wanda has made the expected sharp left-hand turn and is now moving northward, or 010/08 kt. There are no significant changes to the previous forecast track or reasoning. Over the next couple of days, the latest model guidance is in excellent agreement that Wanda should remain embedded within a deep-layer trough, and gradually turn toward the north-northeast later today, followed by a northeastward motion tonight and Wednesday as the cyclone moves through the trough-to-ridge flow pattern. By 48-60 hours, the cyclone is forecast to move toward the east and east-southeast as a ridge builds to the northwest and west of Wanda. The new NHC official forecast track is very similar to the previous advisory track, and lies close to the middle of the simple- and corrected-consensus guidance envelope. The aforementioned improved low-level structure should act to force new convection later today and especially tonight during the nocturnal convective maximum period. Thus, Wanda has another 24-36 h to strengthen while the system remains over marginally warm sea-surface temperatures (SST) near 23 deg C and within a relatively low vertical wind shear environment. Thereafter, slow but steady weakening is likely due to an increase in southwesterly wind shear, a decrease in mid-tropospheric moisture, and a decrease in SSTs. However, baroclinic effects associated with an approaching mid-tropospheric trough from the west could partially offset the weakening process. Wanda is expected become a post-tropical cyclone around 72 h, but this could be delayed if the baroclinic forcing on day 3 ends up stronger than currently expected. The new official intensity forecast is essentially just an update of the previous intensity forecast, and is close to an average of the intensity consensus models IVCN, NOAA-HCCA, and FSSE. FORECAST POSITIONS AND MAX WINDS INIT 02/1500Z 35.6N 40.6W 45 KT 50 MPH 12H 03/0000Z 37.0N 40.0W 45 KT 50 MPH 24H 03/1200Z 38.8N 39.6W 50 KT 60 MPH 36H 04/0000Z 40.7N 39.5W 45 KT 50 MPH 48H 04/1200Z 42.1N 39.3W 45 KT 50 MPH 60H 05/0000Z 42.7N 38.1W 45 KT 50 MPH 72H 05/1200Z 42.5N 36.1W 45 KT 50 MPH...POST-TROPICAL 96H 06/1200Z 41.0N 33.0W 45 KT 50 MPH...POST-TROPICAL 120H 07/1200Z 42.5N 29.5W 40 KT 45 MPH...POST-TROPICAL $$ Forecaster Stewart |