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| #1144108 (Received by flhurricane at: 11:03 AM 17.Jul.2023) TCDAT5 Tropical Depression Don Discussion Number 14 NWS National Hurricane Center Miami FL AL052023 300 PM GMT Mon Jul 17 2023 Satellite images indicate that Don continues to produce a cluster of deep convection, displaced east of the center due to shear. Despite the cool waters, this deep convection has persisted overnight, and the cloud pattern most resembles a sheared tropical cyclone, although the circulation remains elongated. This structure is confirmed by the latest TAFB Dvorak estimate, which gave a tropical classification for the first time at 12 UTC. Thus, Don is changed to a tropical cyclone on this advisory, although it is still a 30-kt depression on the basis of a recent scatterometer pass at 1229 UTC that showed a small area of winds around 30 kt. Don is moving east-southeastward at about 12 kt, with a better estimate of motion available due to the aforementioned scatterometer pass. The depression is about a quarter of the way through making a large anticyclonic loop over the central Atlantic, forced by a blocking ridge to its north. The new forecast is shifted to the east during the next few days as guidance has trended faster with a more vertically intact cyclone structure noted. In the long range, the blocking ridge shifts eastward, allowing Don to turn northwestward and cross over its own path in about 5 days. While the ECMWF still remains east of most of the other guidance, the model consensus is close to the previous forecast, so the new track forecast is about the same as the last prediction. The depression is expected to move over warmer waters by midweek, though some increase in shear could reduce the chances for significant restrengthening (and the waters are only 25 degrees C or so). Still, basically all of the models now bring this to a tropical storm within a few days, and the new forecast continues to follow suit. At long range, the SSTs start to decrease again, and the system is forecast to cross its own path, resulting in less instability due to a presumed cool wake from the storm. I`ve elected to raise the forecast 5 kt in about 4 days, but it is still below most of the guidance, as the environment just doesn`t seem that conducive for a significant increase in winds. FORECAST POSITIONS AND MAX WINDS INIT 17/1500Z 38.6N 42.9W 30 KT 35 MPH 12H 18/0000Z 37.7N 41.1W 30 KT 35 MPH 24H 18/1200Z 36.0N 39.8W 30 KT 35 MPH 36H 19/0000Z 34.5N 39.3W 30 KT 35 MPH 48H 19/1200Z 33.8N 39.8W 35 KT 40 MPH 60H 20/0000Z 33.4N 40.8W 35 KT 40 MPH 72H 20/1200Z 33.7N 42.0W 40 KT 45 MPH 96H 21/1200Z 35.8N 45.5W 45 KT 50 MPH 120H 22/1200Z 39.5N 49.0W 40 KT 45 MPH $$ Forecaster Blake |
