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Tropical Depression Rene Forecast Discussion Number 22
2020-09-12 16:58:46| National Hurricane Center (Atlantic)
Issued at 1100 AM AST Sat Sep 12 2020 000 WTNT43 KNHC 121458 TCDAT3 Tropical Depression Rene Discussion Number 22 NWS National Hurricane Center Miami FL AL182020 1100 AM AST Sat Sep 12 2020 The deep convection associated with Rene has gradually decreased over the past several hours, with only a few sporadic patches remaining. A recent ASCAT overpass showed peak winds of 28 kt in the northeastern quadrant, while the latest Dvorak intensity estimates from TAFB and SAB suggest the system is 30 kt. Therefore the initial intensity is being lowered to 30 kt. The depression is forecast to battle dry air for the next several days, with SHIPS guidance indicating that the mid-level relative humidity will decrease to under 40 percent in a few days. Also, it appears that there will be increasing subsidence over the system starting in a couple of days due to a ridge building to the northwest of the cyclone. Neither of these conditions bode well for maintaining organized deep convection. And, with it anticipated that the depression will struggle to maintain convection it is expected to slowly spin down over the next several days. The official forecast shows Rene degenerating into a remnant low in 5 days, but that timing is low confidence, as the system may generate just enough convection over warm waters to continue to be classified as a tropical cyclone longer than that. The alternative scenario is that the system could become a remnant low or open into a trough even sooner. The NHC intensity forecast is a little lower than the previous one mainly due to the decrease in initial intensity, and is in good agreement with the various intensity consensus values. Rene continues to move northwestward, now at 11 kt. A northwestward motion around the western periphery of a mid-level ridge over the eastern Atlantic should continue into tonight. On Sunday, Rene is forecast to slow down as the ridge builds to the northwest and north of the cyclone. By Tuesday, Rene is expected to turn westward and then west-southwestward to southwestward under the influence of the building ridge. The NHC track forecast is very little changed from the previous one, and is near the middle of the track guidance. FORECAST POSITIONS AND MAX WINDS INIT 12/1500Z 23.2N 44.4W 30 KT 35 MPH 12H 13/0000Z 24.5N 45.8W 30 KT 35 MPH 24H 13/1200Z 26.0N 47.0W 30 KT 35 MPH 36H 14/0000Z 27.0N 47.7W 30 KT 35 MPH 48H 14/1200Z 27.3N 48.2W 25 KT 30 MPH 60H 15/0000Z 27.0N 48.7W 25 KT 30 MPH 72H 15/1200Z 26.3N 49.8W 25 KT 30 MPH 96H 16/1200Z 25.0N 52.6W 25 KT 30 MPH 120H 17/1200Z 24.0N 56.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Latto
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