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| #1151778 (Received by flhurricane at: 10:56 PM 07.Sep.2023) TCDAT4 Tropical Storm Margot Discussion Number 3 NWS National Hurricane Center Miami FL AL142023 200 AM CVT Fri Sep 08 2023 The convective organization of Margot has changed little tonight. The storm is producing some sheared convection to the north of its center with modest signs of curvature. An earlier 37 GHz GMI microwave image of Margot suggested the low-level center was a bit south of previous estimates, and this is consistent with the now partially exposed center that has emerged in recent proxy-visible imagery. The satellite intensity estimates are unchanged from earlier today, and the intensity remains 35 kt for this advisory. The SSTs along Margot's track are plenty warm enough to support some intensification over the next few days. On the other hand, there is a good amount of dry air in the surrounding environment, and southwesterly deep-layer shear is forecast to increase over Margot during the next several days in association with an upper-level trough over the central Atlantic. Interestingly, the increased shear diagnosed from the SHIPS guidance occurs around the same time as increasing upper-level divergence over the cyclone. This seems to suggest that some of the intensification in the global models could be driven by positive interaction with the upper trough. Since most of the global and regional hurricane models show Margot becoming a hurricane during the next few days, the NHC forecast follows suit and shows slow strengthening throughout the period. This forecast lies between the latest HCCA and IVCN multi-model aids. Margot is moving west-northwestward at 295/14 kt around a ridge over the eastern Atlantic. This general motion should continue for the next couple of days, followed by a turn toward the northwest and north-northwest at a slightly slower forward speed at days 3-5 as a weakness develops in the subtropical ridge. The track model consensus this cycle has trended slower and to the left of the previous prediction. As a result, the updated NHC track forecast has been adjusted accordingly. FORECAST POSITIONS AND MAX WINDS INIT 08/0300Z 16.8N 29.3W 35 KT 40 MPH 12H 08/1200Z 17.5N 31.6W 40 KT 45 MPH 24H 09/0000Z 18.6N 34.4W 45 KT 50 MPH 36H 09/1200Z 19.9N 36.8W 50 KT 60 MPH 48H 10/0000Z 21.2N 38.7W 55 KT 65 MPH 60H 10/1200Z 22.7N 40.1W 60 KT 70 MPH 72H 11/0000Z 24.5N 41.0W 65 KT 75 MPH 96H 12/0000Z 28.0N 42.5W 75 KT 85 MPH 120H 13/0000Z 31.0N 43.0W 80 KT 90 MPH $$ Forecaster Reinhart |
