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Tropical Storm Paulette Forecast Discussion Number 19
2020-09-11 16:44:59| National Hurricane Center (Atlantic)
Issued at 1100 AM AST Fri Sep 11 2020 000 WTNT42 KNHC 111444 TCDAT2 Tropical Storm Paulette Discussion Number 19 NWS National Hurricane Center Miami FL AL172020 1100 AM AST Fri Sep 11 2020 Despite what is being analyzed as roughly 40 kt of deep-layer southwesterly shear, Paulette's center is embedded beneath the cirrus canopy of a strong convective burst to the north. Recent microwave images do confirm, however, that the center remains displaced from the convection. We have not yet received new scatterometer data over Paulette, and since the structure has not degraded from overnight, the initial intensity remains 55 kt. This is in best agreement with the Dvorak estimate from TAFB. Paulette appears to have turned toward the northwest (305/9 kt) based on center fixes over the past 12 hours. A weakness in the subtropical ridge is beginning to develop to the north of Paulette, which should allow the cyclone to maintain a motion toward the northwest or west-northwest during the next 3 days. After that time, a longwave trough forecast to move across the northeastern United States is expected to erode the ridge eastward, causing Paulette to recurve sharply toward the north and northeast in the vicinity of Bermuda on days 4 and 5. Except for some minor speed differences, the track models agree on this general trajectory and have less east-to-west spread during the recurvature phase than they did yesterday. The GFS, ECMWF, HCCA, and Florida State Superensemble aids all lie along the western side of the guidance envelope at the time of recurvature, and as a result the new NHC track has been nudged a little west of the previous prediction during that period in deference to those normally reliable models. The shear affecting Paulette is forecast to abate over the next 48 hours while the storm also moves over warmer ocean waters and into a more unstable environment. Given the cyclone's hardiness in the face of the ongoing shear, Paulette is unlikely to have problems responding to the improving environment. Paulette is now forecast to become a hurricane in 36 hours, which is supported by the latest dynamical hurricane models, the superensemble aids, and the IVCN intensity consensus. Continued strengthening is anticipated after 36 hours, with Paulette likely to reach a peak intensity in 4-5 days. Key Messages: 1. Paulette is expected to approach Bermuda as a hurricane this weekend and make its closest approach to the island on Monday. While the exact details of Paulette's track and intensity near the island are not yet known, the risk of strong winds, storm surge, and heavy rainfall on Bermuda continues to increase. 2. Swells produced by Paulette are affecting portions of the Leeward Islands and will continue to spread westward to the Greater Antilles, the Bahamas, Bermuda, and the southeastern United States into the weekend. These swells could cause life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 11/1500Z 23.6N 52.2W 55 KT 65 MPH 12H 12/0000Z 24.6N 53.7W 55 KT 65 MPH 24H 12/1200Z 26.1N 55.5W 60 KT 70 MPH 36H 13/0000Z 27.6N 57.5W 65 KT 75 MPH 48H 13/1200Z 28.9N 59.9W 75 KT 85 MPH 60H 14/0000Z 30.2N 62.5W 80 KT 90 MPH 72H 14/1200Z 31.6N 64.3W 85 KT 100 MPH 96H 15/1200Z 34.5N 63.5W 90 KT 105 MPH 120H 16/1200Z 37.0N 58.0W 90 KT 105 MPH $$ Forecaster Berg
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