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| #1152652 (Received by flhurricane at: 10:59 AM 13.Sep.2023) TCDAT4 Hurricane Margot Discussion Number 25 NWS National Hurricane Center Miami FL AL142023 Issued by the NWS Weather Prediction Center College Park MD 300 PM GMT Wed Sep 13 2023 Margot continues to exhibit a double eyewall structure based on a recent SAR pass over the storm, with a well-defined inner core. GOES-16 IR data shows the inner-eye feature occasionally obscured by clouds, but overall the organization of Margot has changed little over the last several hours. The latest microwave data in conjunction with the SAR pass suggests the initial intensity may be just a tad stronger compared to continuity, and so it will be set at 80 kt for this advisory. Margot is slowing down as it moves within the flow between a deep-layer ridge over the eastern Atlantic and a narrow upper trough to its west. A general north to north-northwest motion should continue over the next day or so before the track forecast becomes very challenging. Margot is expected to become caught in weak steering currents, with the global models showing a blocking ridge developing to the north of the cyclone by late week into the weekend. There are significant differences between the GFS and ECMWF with regards to the strength and position of this ridge, which has large implications in the longer-range track of Margot. The overall consensus of the guidance suggests that Margot could make a clockwise loop as the ridge builds, and the latest NHC forecast shows little net motion between 36-72 hrs as the cyclone meanders over the central Atlantic. At days 4-5, most models (except for the ECMWF) show the ridge sliding eastward, allowing for Margot to gain latitude, and the overall track forecast confidence remains low. The deep-layer shear is forecast to increase during the next 24 to 36 hrs, and this coupled with a likelihood of the upwelling of cooler waters should result in a weakening trend. Drier air surrounding the storm will also be a factor in causing a weakening cyclone going into the weekend. The NHC intensity forecast is close to the previous forecast and shows gradual decrease in strength through 72 hrs, and in good agreement with the consensus of the intensity aids. Although this forecast keeps Margot a tropical cyclone through day 5, simulated satellite imagery from the global models suggests these environmental factors could cause the system to lose organized convection and become post-tropical early next week as the storm lingers west of the Azores. FORECAST POSITIONS AND MAX WINDS INIT 13/1500Z 34.1N 40.4W 80 KT 90 MPH 12H 14/0000Z 35.0N 40.7W 75 KT 85 MPH 24H 14/1200Z 36.0N 40.2W 75 KT 85 MPH 36H 15/0000Z 36.8N 39.5W 70 KT 80 MPH 48H 15/1200Z 36.9N 39.4W 65 KT 75 MPH 60H 16/0000Z 36.5N 39.4W 60 KT 70 MPH 72H 16/1200Z 36.3N 40.2W 50 KT 60 MPH 96H 17/1200Z 36.0N 42.5W 45 KT 50 MPH 120H 18/1200Z 38.0N 42.5W 45 KT 50 MPH $$ Forecaster Orrison/Blake |
