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| #941632 (Received by flhurricane at: 4:42 AM 24.Sep.2018) TCDAT3 Subtropical Storm Leslie Discussion Number 4 NWS National Hurricane Center Miami FL AL132018 500 AM AST Mon Sep 24 2018 Leslie has changed little overnight. The large subtropical cyclone continues to produce patches of deep convection, mostly to the south and east of the center. The initial intensity is again held at 35 kt, which is near the upper end of the satellite intensity estimates. The subtropical storm is moving southward at 5 kt. The steering currents around Leslie are expected to collapse later today and little overall motion is forecast during the next 12-18 hours. After that time, a cold front is expected to approach the system, and that should cause Leslie to move eastward tonight and Tuesday. The front is expected to merge with Leslie by Tuesday night, causing it to become extratropical. While little change in intensity is expected during the next day or so, due to dry air and moderate shear, some strengthening as an extratropical low is likely due to baroclinic forcing. In fact, after becoming extratropical, the models show Leslie merging with another frontal low to its north, leading to the formation of a powerful slow-moving non-tropical low with gale- or storm-force winds over the central Atlantic later this week. FORECAST POSITIONS AND MAX WINDS INIT 24/0900Z 32.6N 48.6W 35 KT 40 MPH 12H 24/1800Z 32.6N 48.3W 35 KT 40 MPH 24H 25/0600Z 32.6N 46.9W 35 KT 40 MPH 36H 25/1800Z 32.5N 44.8W 35 KT 40 MPH 48H 26/0600Z 32.7N 42.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 72H 27/0600Z...MERGED WITH FRONTAL SYSTEM $$ Forecaster Cangialosi |