000 WTNT43 KNHC 090837 TCDAT3 Hurricane Leslie Discussion Number 28 NWS National Hurricane Center Miami FL AL132024 500 AM AST Wed Oct 09 2024 Conventional satellite imagery shows that Leslie's cloud pattern has changed little during the past few hours. Earlier SSMIS and AMSU-B microwaves overpasses, however, indicated that Leslie's structure has become vertically tilted southeast to northwest, indicative of the previously mentioned mid-level southerly shear component. A blend of the Dvorak satellite intensity estimates from TAFB and SAB and a 0610 UTC UW-CIMSS 72 kt SATCON analysis yield an initial intensity at 70 kt. Although the undercutting shear is expected to persist, slight intensity fluctuations are possible today and tonight while Leslie moves through a marginally conducive thermodynamic environment and over warm oceanic surface temperatures. Afterward, the global models show an upper-tropospheric anticyclone developing over the SW Atlantic, between Milton and Leslie. This feature is expected to spread moderate northerly shear over the central subtropical Atlantic inhibiting ventilation aloft over the north portion of the cyclone. Consequently, weakening is expected, and Leslie is forecast to quickly lose its associated convection and become a post-tropical cyclone in 3 days. Leslie's initial motion is estimated to be northwestward, 310/9 kt, and this general motion is expected to continue during the next couple of days. By mid-period, the cyclone is forecast to slow in forward speed and turn toward the north while rounding the southwestern periphery of a subtropical ridge to the northeast. Afterward, Leslie should accelerate and turn toward the northeast in response to a major shortwave trough approaching the cyclone from the northeast. The NHC forecast is close to the previous one and is based on a compromise of the TVCN and HCCA consensus models. Leslie's wind radii were adjusted based on 2354 UTC METOP-B and 0049 UTC METOP-C scatterometer passes. FORECAST POSITIONS AND MAX WINDS INIT 09/0900Z 21.2N 47.8W 70 KT 80 MPH 12H 09/1800Z 22.0N 48.6W 75 KT 85 MPH 24H 10/0600Z 23.0N 49.5W 75 KT 85 MPH 36H 10/1800Z 23.9N 50.0W 65 KT 75 MPH 48H 11/0600Z 25.4N 50.0W 55 KT 65 MPH 60H 11/1800Z 27.6N 48.8W 45 KT 50 MPH 72H 12/0600Z 30.0N 46.1W 40 KT 45 MPH...POST-TROPICAL 96H 13/0600Z 34.3N 36.8W 35 KT 40 MPH...POST-TROPICAL 120H 14/0600Z 35.4N 28.9W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ Forecaster Roberts
Hurricane Leslie Forecast Discussion
09
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