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Tropical Storm Paulette Forecast Discussion Number 40
2020-09-22 04:35:24| National Hurricane Center (Atlantic)
Issued at 300 AM GMT Tue Sep 22 2020 000 WTNT41 KNHC 220235 TCDAT1 Tropical Storm Paulette Discussion Number 40 NWS National Hurricane Center Miami FL AL172020 300 AM GMT Tue Sep 22 2020 Deep convection associated with the post-tropical remnants of Paulette that moved southward to the southwest of the Azores over the past few days has become better organized over the past 6-12 hours. An ASCAT over pass from a few hours ago indicate that increase in convective organization has result in strengthening and the system is being classified as a tropical cyclone once again. The ASCAT revealed peak winds of just over 45 kt, and given that instruments typical undersampling, the initial intensity is set at 50 kt. The scatterometer data also indicated a small radius of maximum winds of about 30 n mi, therefore the system is being classified as a tropical cyclone rather than subtropical. Paulette is moving east-northeastward or 075/14 kt. The tropical storm should continue moving east-northeastward ahead of a mid-latitude trough dropping southeastward over the northeastern Atlantic, and the global models are in reasonably good agreement through 24-36 hours. After that time, there is significant bifurcation in the track guidance with the GFS, HWRF, and HMON all taking a stronger Paulette faster east-northeastward over the eastern Atlantic, while the UKMET and ECMWF show a weaker cyclone slowing down and turning west-southwestward in the low-level steering flow late in the forecast period. The NHC track forecast shows Paulette slowing down and turning southward, and then southwestward between 48-96 h, but it's not nearly as far west as the UKMET and ECMWF models. Given the large spread in the track guidance at that time period, the NHC forecast is near the HFIP corrected consensus. Paulette is already over marginal SSTs and cooler waters lie ahead along the forecast track. This, along with moderate vertical wind shear should result in gradual weakening beginning on Tuesday. The NHC intensity forecast calls for Paulette to weaken to a tropical depression in 48-60 h, and become a remnant low shortly thereafter. FORECAST POSITIONS AND MAX WINDS INIT 22/0300Z 33.9N 25.3W 50 KT 60 MPH 12H 22/1200Z 34.4N 22.8W 50 KT 60 MPH 24H 23/0000Z 34.7N 20.4W 45 KT 50 MPH 36H 23/1200Z 35.1N 18.2W 40 KT 45 MPH 48H 24/0000Z 35.3N 16.8W 35 KT 40 MPH 60H 24/1200Z 34.7N 16.3W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 25/0000Z 34.0N 16.3W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 26/0000Z 33.1N 18.4W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 27/0000Z...DISSIPATED $$ Forecaster Brown
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