ZCZC MIATCDEP3 ALL TTAA00 KNHC DDHHMM Hurricane Marie Discussion Number 18 NWS National Hurricane Center Miami FL EP182020 800 AM PDT Sat Oct 03 2020 Marie shows little signs of weakening this morning as its satellite presentation remains impressive. A closed ring of eyewall convection with cloud top temperatures colder than -65 degrees C surrounds a well-defined 20 nm eye. The initial intensity is maintained at 115 kt based on a T6.0 Dvorak classification from SAB, which is supported by the latest ADT estimates. Marie is approaching an environment of increasing deep-layer southwesterly shear and SSTs below 26 degrees Celsius, which should induce weakening beginning later today that will continue through early next week. The latest SHIPS guidance indicates the vertical wind shear will strengthen to 30 kt by Mon and continue increasing through the end of the 5-day forecast period. Therefore, Marie is forecast to weaken to a tropical storm by early Monday and a tropical depression by the middle of next week. The NHC intensity forecast is held a bit higher than the model consensus through the first 12-24 hours of the forecast, since Marie has yet to show signs of weakening. As the environmental conditions become increasingly hostile, the official forecast shows more rapid weakening in line with the consensus intensity guidance. By day 5, simulated satellite imagery suggests the system will be a remnant low devoid of deep convection. Marie's initial motion is 310/8 kt, and the system is expected to generally continue moving northwestward for the next several days along the southwest periphery of a mid-level ridge. A deep-layer trough is expected to dig north of Marie during the middle of next week, which should begin turning the system more northward toward the end of the 5-day forecast period. A larger spread in the guidance is noted at days 4-5, as it remains somewhat unclear how much the trough will influence the weakening system based on timing differences between the GFS and ECMWF models. Overall, the NHC track forecast remains fairly close to the previous one, with slight changes based on the consensus aids including TVCE and HCCA. FORECAST POSITIONS AND MAX WINDS INIT 03/1500Z 18.4N 126.9W 115 KT 130 MPH 12H 04/0000Z 19.1N 127.7W 105 KT 120 MPH 24H 04/1200Z 20.0N 128.7W 90 KT 105 MPH 36H 05/0000Z 20.6N 129.8W 70 KT 80 MPH 48H 05/1200Z 21.2N 131.2W 55 KT 65 MPH 60H 06/0000Z 21.9N 132.4W 45 KT 50 MPH 72H 06/1200Z 22.5N 133.7W 40 KT 45 MPH 96H 07/1200Z 23.5N 135.5W 30 KT 35 MPH 120H 08/1200Z 24.5N 136.5W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ Forecaster Reinhart/Berg NNNN