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| #1152601 (Received by flhurricane at: 7:42 AM 13.Sep.2023) TCDAT4 Hurricane Margot Discussion Number 24 NWS National Hurricane Center Miami FL AL142023 900 AM GMT Wed Sep 13 2023 The eye of Margot has been obscured by clouds to varying degrees overnight, but has begun to warm in the latest infrared satellite images this morning. Recent AMSR2 microwave images reveal the hurricane has a compact inner core, with a concentric outer ring of convection that is broken to the northwest. Earlier scatterometer data indicated a secondary wind maximum exists within this outer band. The vortex is slightly tilted with height, as the mid-level 89-GHz eye lies to the southwest of the 37-GHz center. The intensity for this advisory remains 75 kt based on consensus T4.5 Dvorak classifications from TAFB and SAB. Margot has begun to slow down while moving northward (350/10 kt) within the flow between a deep-layer ridge over the eastern Atlantic and a narrow upper trough to its west. A general northward motion should continue over the next day or so before the track forecast becomes very challenging. Margot is forecast 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. Based on the overall shift in the guidance suite this cycle, the latest NHC forecast shows little net motion between 36-72 h as Margot meanders over the central Atlantic. This is a fairly large departure from the previous advisory, but better represents the latest consensus track solutions. At days 4-5, most models (except for the ECMWF) show the ridge sliding eastward, but overall track forecast confidence is very low and larger future adjustments could be necessary. It is possible that Margot is at or near its peak intensity. The deep-layer shear is forecast to increase during the next 24 h, and thereafter the coupled atmosphere-ocean models indicate the slow motion of the storm is likely to result in upwelling of cooler waters. In addition, the surrounding environment is expected to become drier and more subsident by this weekend. The NHC intensity forecast has been lowered from the previous one and shows steady weakening beyond 36 h, in good agreement with the latest HCCA and IVCN 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. FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 33.6N 40.0W 75 KT 85 MPH 12H 13/1800Z 34.5N 40.5W 75 KT 85 MPH 24H 14/0600Z 35.6N 40.5W 70 KT 80 MPH 36H 14/1800Z 36.5N 39.9W 70 KT 80 MPH 48H 15/0600Z 36.9N 39.5W 65 KT 75 MPH 60H 15/1800Z 36.7N 39.4W 60 KT 70 MPH 72H 16/0600Z 36.5N 39.7W 55 KT 65 MPH 96H 17/0600Z 36.5N 42.5W 45 KT 50 MPH 120H 18/0600Z 38.0N 43.0W 40 KT 45 MPH $$ Forecaster Reinhart |
