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#1048800 (Received by flhurricane at: 10:48 PM 14.Jun.2021) TCDAT2 Tropical Storm Bill Discussion Number 3 NWS National Hurricane Center Miami FL AL022021 1100 PM AST Mon Jun 14 2021 Deep convection has increased in a cluster to the northeast of the estimated center. Scatterometer measurements showed a couple of 40-41 kt vectors over the southeastern quadrant of the cyclone. On this basis, the estimated intensity is increased to 40 kt, which makes this the second tropical storm of the season, albeit a rather high-latitude one. The system is in an environment of fairly strong southwesterly shear, but the diffluent upper-level flow has apparently contributed to some strengthening in a seemingly hostile environment. Some additional short-term strengthening could occur but by 36 hours, the cyclone should merge with a baroclinic zone while approaching Newfoundland and become extratropical. This transition is also shown by the FSU cyclone phase analyses of the GFS model fields. Bill is moving fairly swiftly northeastward, or 055/20 kt. The track forecast appears to be straightforward. The flow ahead of a large mid-tropospheric trough near the United States east coast should accelerate the system northeastward for the next day or two, and until the system dissipates. The NHC track forecast is similar to the previous one and not far from the model consensus. FORECAST POSITIONS AND MAX WINDS INIT 15/0300Z 36.7N 69.8W 40 KT 45 MPH 12H 15/1200Z 38.9N 65.1W 45 KT 50 MPH 24H 16/0000Z 42.6N 59.6W 40 KT 45 MPH 36H 16/1200Z 46.5N 54.5W 35 KT 40 MPH...POST-TROP/EXTRATROP 48H 17/0000Z...DISSIPATED $$ Forecaster Pasch |