Show Selection: |
#1152775 (Received by flhurricane at: 4:50 AM 14.Sep.2023) TCDAT4 Hurricane Margot Discussion Number 28 NWS National Hurricane Center Miami FL AL142023 900 AM GMT Thu Sep 14 2023 The satellite structure of Margot has continued to deteriorate. The low-level center has been partially exposed in GOES-16 proxy-visible satellite images, and recent AMSR2 microwave data show the inner core convection has eroded. These changes appear to be the result of some southwesterly shear over the system and dry air intrusions into the circulation. Presently, deep convection is limited to a couple of curved bands that wrap around the northern portion of the system. The objective and subjective satellite intensity estimates have markedly decreased, and the initial intensity is lowered to 65 kt, in best agreement with recent UW-CIMSS SATCON and TAFB Dvorak current intensity estimates. However, this could be generous given the rapidly degrading satellite presentation. Margot continues to slow down this morning, and it appears the center has recently turned north-northeastward (015/5 kt). The cyclone is likely to stall and meander over the next couple of days in response to a building ridge to its north and west. In general, the track models agree that Margot will make a gradual clockwise loop while it pivots around the ridge that is forecast to slowly slide eastward over the weekend. However, there is still large spread in the various model solutions while the steering currents remain weak. The updated NHC forecast tries to reflect the latest trends of the multi-model consensus aids and shows little movement between 12-60 h. By early next week, the ridge should become re-positioned to the east of Margot, allowing the system to turn northward and become caught up in the mid-latitude westerlies. In addition to the ongoing shear, several factors suggest Margot is likely to continue weakening during the next several days. The cyclone is over marginal SSTs, and the coupled atmosphere-ocean models indicate the slow-moving storm is likely to upwell even cooler waters while it meanders over the central Atlantic. Also, more bouts of dry air entrainment within a drier and more subsident environment will make it difficult for Margot to sustain convection near its center, as suggested by the GFS and ECMWF simulated satellite imagery. The NHC forecast shows continued weakening through early next week with Margot becoming extratropical in 120 h while accelerating into the mid-latitudes. Although not explicitly forecast, it is noted that the hostile conditions could render Margot devoid of deep convection even sooner. FORECAST POSITIONS AND MAX WINDS INIT 14/0900Z 35.9N 40.3W 65 KT 75 MPH 12H 14/1800Z 36.4N 39.8W 60 KT 70 MPH 24H 15/0600Z 36.6N 39.2W 55 KT 65 MPH 36H 15/1800Z 36.4N 39.0W 55 KT 65 MPH 48H 16/0600Z 35.9N 39.5W 50 KT 60 MPH 60H 16/1800Z 35.4N 40.6W 50 KT 60 MPH 72H 17/0600Z 35.2N 42.0W 45 KT 50 MPH 96H 18/0600Z 37.5N 43.3W 45 KT 50 MPH 120H 19/0600Z 40.5N 39.0W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Reinhart |