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| #1139996 (Received by flhurricane at: 4:51 PM 19.Jun.2023) TCDAT3 Tropical Storm Bret Discussion Number 2 NWS National Hurricane Center Miami FL AL032023 500 PM AST Mon Jun 19 2023 Satellite imagery continues to show that the system is becoming better organized. GOES 1-min data shows convective banding and a dense central overcast, with the low-level center embedded on the northwest side of the overcast. Given the satellite trends and latest Dvorak estimates from SAB and TAFB, the initial intensity is set to 35 kt, and the depression is named Tropical Storm Bret. Environmental conditions appear conducive for further strengthening over the next few days, with much warmer than normal SSTs along with plentiful mid-level moisture and light shear. The NHC forecast continues to show a gradual increase in wind speed, similar to the model consensus. However, vertical wind shear is forecast to increase by most of the model guidance on day 3 in response to an upper-level trough, along with more dry air nearby. Thus, the NHC forecast shows a slow weakening after that point while Bret is over the eastern Caribbean. There continues to be larger than usual uncertainty, due to the wide spread between the stronger regional hurricane models and weaker global guidance. The initial motion estimate is 280/18 kt. A large ridge of high pressure over the central Atlantic Ocean is forecast to cause Bret to move westward over the next several days. As the system nears the Lesser Antilles late this week, the ridge should weaken, causing the storm to move more toward the west-northwest. The main source of track uncertainty continues to be tied to how strong Bret becomes, with the models farthest to the right (HWRF, HAFS) being stronger than the consensus, while the left-leaning models (ECMWF, UKMET) showing significant weakening at long range. Given the large track and intensity spread, the NHC forecast remains near the model consensus, only a bit faster than the previous cycle. The latest forecast remains a low confidence prediction. KEY MESSAGES: 1. Bret is forecast to strengthen and move across the Lesser Antilles as a hurricane on Thursday and Friday, bringing a risk of flooding from heavy rainfall, hurricane-force winds, and dangerous storm surge and waves. 2. Given the larger than usual uncertainty in the track forecast, it is too early to specify the location and magnitude of where these hazards could occur. However, everyone in the Lesser Antilles, Puerto Rico, and the Virgin Islands should closely monitor updates to the forecast for Bret and have their hurricane plan in place. FORECAST POSITIONS AND MAX WINDS INIT 19/2100Z 11.3N 42.2W 35 KT 40 MPH 12H 20/0600Z 11.7N 44.8W 40 KT 45 MPH 24H 20/1800Z 12.2N 47.7W 50 KT 60 MPH 36H 21/0600Z 12.7N 50.3W 60 KT 70 MPH 48H 21/1800Z 13.2N 52.9W 65 KT 75 MPH 60H 22/0600Z 13.7N 55.5W 70 KT 80 MPH 72H 22/1800Z 14.3N 58.3W 70 KT 80 MPH 96H 23/1800Z 15.5N 63.6W 65 KT 75 MPH 120H 24/1800Z 17.0N 68.5W 60 KT 70 MPH $$ Forecaster Blake/Kelly |
