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Tropical Storm Paulette Forecast Discussion Number 14
2020-09-10 10:37:35| National Hurricane Center (Atlantic)
Issued at 500 AM AST Thu Sep 10 2020 000 WTNT42 KNHC 100837 TCDAT2 Tropical Storm Paulette Discussion Number 14 NWS National Hurricane Center Miami FL AL172020 500 AM AST Thu Sep 10 2020 Although Paulette's center of circulation has separated farther south from the cloud mass during the past several hours, the cyclone is still producing an area of deep convection consisting of -79C cold cloud tops. Earlier scatterometer data indicated surface winds of 45-50 kt in this region of coldest cloud tops, so it's reasonable to think that those winds are still present. Therefore, the initial intensity is held at 50 kt for this advisory. Both the ECMWF and FV3 SHIPS intensity models show the shear magnitude increasing to 35-40 kt today. As a result, Paulette is expected to begin weakening by this evening. Over the weekend, however, the shear is forecast to decrease gradually and shift from the southeast and become a bit more diffluent, which should allow for reintensification. Several of the skilled intensity guidance, including the aforementioned SHIPS, and the consensus models, HCCA and IVCN, now show Paulette as a hurricane in 4 days, or sooner (COAMPS-TC). The official intensity forecast is once again adjusted upward, and lies between the HCCA (a little higher) and the Decay SHIPS intensity guidance. The initial motion is estimated to be west-northwestward, or 290/9 kt and Paulette should continue in this general motion through Friday as a mid-tropospheric ridge temporarily builds over the central Atlantic in response to a mid- to upper-level trough, extending southwestward from the Azores Islands, weakening and lifting northeastward. By Saturday morning, a break in the aforementioned ridge develops due to a combination of mid- to upper-level low situated to the northwest of the cyclone and a mid-latitude shortwave trough moving off of the northeast U.S. This change in the synoptic steering pattern should cause the tropical cyclone to turn toward the northwest with an increase in forward speed. The NHC track forecast is close to the previous advisory, but a little faster beyond 48 hours, and is shifted to the left, closer to the HCCA and TVCN consensus models at days 4 and 5. FORECAST POSITIONS AND MAX WINDS INIT 10/0900Z 20.9N 49.0W 50 KT 60 MPH 12H 10/1800Z 21.3N 50.4W 50 KT 60 MPH 24H 11/0600Z 21.8N 52.4W 45 KT 50 MPH 36H 11/1800Z 22.8N 54.2W 40 KT 45 MPH 48H 12/0600Z 24.1N 55.9W 40 KT 45 MPH 60H 12/1800Z 25.7N 57.5W 45 KT 50 MPH 72H 13/0600Z 27.1N 59.4W 50 KT 60 MPH 96H 14/0600Z 29.7N 63.7W 65 KT 75 MPH 120H 15/0600Z 32.0N 64.9W 75 KT 85 MPH $$ Forecaster Roberts
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