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| #1140244 (Received by flhurricane at: 10:51 PM 20.Jun.2023) TCDAT3 Tropical Storm Bret Discussion Number 7 NWS National Hurricane Center Miami FL AL032023 1100 PM AST Tue Jun 20 2023 Bret has become a little better organized this evening, with increased convection near and north of the center and some outer bands developing in the eastern semicircle. This development has lead to satellite intensity estimates from TAFB and SAB increasing to 45 kt, and that will be the initial intensity for this advisory. Unfortunately, the ASCAT overpasses this evening again managed to miss Bret. Satellite imagery continues to suggest some vertical wind shear is undercutting Bret`s otherwise favorable looking outflow pattern and slowing the rate of intensification. This shear is expected to continue for the next 36 h or so, and the storm is forecast to continue to slowly strengthen during this time. The new intensity forecast calls for Bret to have a 55-kt intensity when it passes near or over the Lesser Antilles around the 48-h point. After that, stronger shear associated with an upper-level trough over the eastern Caribbean should stop intensification and cause Bret to weaken. Indeed, the global models continue to forecast the system to degenerate to a tropical wave by 96 h. The new intensity forecast will continue to have a 96 h point followed by dissipation before 120 h. However, it will show a faster weakening from 72-96 h than the previous forecast. The initial motion is westward or 280/15 kt. There is again little change to either the track forecast guidance or the track forecast since the last advisory, with low- to mid-level ridging north of Bret expected to steer the cyclone westward through dissipation. Users are reminded that NHC`s track forecasts have average errors of about 60 n mi at 48 hours, and it is too soon to know exactly where Bret`s center will move across the Lesser Antilles chain. KEY MESSAGES: 1. Bret is forecast to approach the Lesser Antilles through Thursday morning and then move across the islands Thursday afternoon and Thursday night as a tropical storm, bringing a risk of flooding from heavy rainfall, strong winds, and dangerous waves along the coast. 2. Given the uncertainty in the track and intensity forecasts, it is too early to specify the location and magnitude of where Bret`s associated hazards could occur. A Tropical Storm Watch has been issued for Barbados, Dominica, Martinique, and St. Lucia, and additional watches and warnings are likely for these and other islands in the Lesser Antilles on Wednesday. FORECAST POSITIONS AND MAX WINDS INIT 21/0300Z 12.5N 50.2W 45 KT 50 MPH 12H 21/1200Z 12.9N 52.3W 50 KT 60 MPH 24H 22/0000Z 13.3N 54.7W 55 KT 65 MPH 36H 22/1200Z 13.7N 57.5W 55 KT 65 MPH 48H 23/0000Z 14.0N 60.6W 55 KT 65 MPH 60H 23/1200Z 14.3N 63.9W 50 KT 60 MPH 72H 24/0000Z 14.6N 67.6W 45 KT 50 MPH 96H 25/0000Z 15.0N 75.0W 30 KT 35 MPH 120H 26/0000Z...DISSIPATED $$ Forecaster Beven |
