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Tropical Storm Leslie Forecast Discussion Number 52
2018-10-09 10:57:56| National Hurricane Center (Atlantic)
Issued at 500 AM AST Tue Oct 09 2018 000 WTNT43 KNHC 090857 TCDAT3 Tropical Storm Leslie Discussion Number 52 NWS National Hurricane Center Miami FL AL132018 500 AM AST Tue Oct 09 2018 Leslie has been steady state overnight. The low-level center is estimated to be on the southern side of a persistent area of deep convection. The satellite intensity estimates are largely unchanged, so the initial intensity is held at 55 kt for this advisory. The tropical storm is moving southeastward at 11 kt steered by the flow on the southwest side of a broad mid- to upper-level trough. This motion, but a slower pace, is expected during the next 24 to 36 hours as the trough pulls away. After that time, another trough is expected to dig southward over the north Atlantic, which should cause Leslie to accelerate east-northeastward. Although the models are in fair agreement for the next few days, they remain in in poor agreement on whether or not the trough will continue to carry Leslie eastward or leave the storm behind around day 5. The GFS and ECMWF have flip flopped, with the GFS now showing Leslie meandering over the east Atlantic by day 5 and the ECMWF moving the system eastward toward Morocco. The ensemble spread remains large in those two global models and there has not been much run-to-run consistency either. The NHC track forecast remains near the various consensus aids, which is usually a good place to be when there is considerable uncertainty like this. Leslie should slowly strengthen during the next few days while it moves over slightly warmer waters and into a more moist environment. These favorable conditions should allow Leslie to become a hurricane once again, likely within a day or two. Weakening is expected to commence this weekend when Leslie is forecast to move over cooler waters and into an atmosphere of stronger shear and drier air, and the system is forecast to become post-tropical by day 5. However, the long range intensity forecast is strongly linked to where Leslie will be, so since the track forecast is uncertain, the intensity prediction is likewise. FORECAST POSITIONS AND MAX WINDS INIT 09/0900Z 32.2N 43.9W 55 KT 65 MPH 12H 09/1800Z 30.8N 43.1W 55 KT 65 MPH 24H 10/0600Z 29.2N 42.5W 60 KT 70 MPH 36H 10/1800Z 28.1N 42.0W 65 KT 75 MPH 48H 11/0600Z 28.4N 40.5W 65 KT 75 MPH 72H 12/0600Z 31.2N 33.8W 75 KT 85 MPH 96H 13/0600Z 33.5N 23.0W 70 KT 80 MPH 120H 14/0600Z 34.0N 17.0W 55 KT 65 MPH...POST-TROPICAL $$ Forecaster Cangialosi
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