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| #1145051 (Received by flhurricane at: 4:42 PM 23.Jul.2023) TCDAT5 Tropical Storm Don Discussion Number 39 NWS National Hurricane Center Miami FL AL052023 500 PM AST Sun Jul 23 2023 Tropical Storm Don is moving northeastward this afternoon over the North Atlantic`s cooler sea surface temperatures, and deep convection is starting to wane. The convective band from earlier this morning has become more fragmented and not as well defined. Visible satellite and a microwave AMSR2 pass earlier however, still showed that Don has a compact low-level center, and a scatterometer ASCAT-B pass showed winds of 48-50 kt in the southeast quadrant. Subjective Dvorak estimates from TAFB and SAB have also started to trend downward with this advisory cycle. Given the ASCAT-B pass and the subjective satellite estimates, the initial intensity for this advisory is lowered to 50 kt. Don is starting to lose its overall convective pattern and should begin to rapidly weaken tonight and tomorrow. Available global model guidance suggest that Don should lose any remaining deep convection within the next 18 to 24 hours and become a post-tropical cyclone at that time. The intensity forecast remains similar to the previous forecast, with Don dissipating in about 48 hours. The system is moving to the northeast at 15 kt. Don will continue to move to the northeast, with a slight increase in forward speed the remainder of today, before turning to the east-northeast tomorrow due to the steering flow around the northern side of the subtropical ridge. Guidance remains tightly clustered, and there was very little change to the forecast this cycle. The storm is moving up the list of longest-lasting tropical cyclones on record for July (including subtropical stages). Preliminary, Don is tied for 10th, and the cyclone could make the top 5 longest-lasting for July if it lasts through early Monday. FORECAST POSITIONS AND MAX WINDS INIT 23/2100Z 45.2N 46.5W 50 KT 60 MPH 12H 24/0600Z 46.6N 44.1W 40 KT 45 MPH 24H 24/1800Z 47.9N 39.8W 30 KT 35 MPH...POST-TROPICAL 36H 25/0600Z 48.8N 34.7W 30 KT 35 MPH...POST-TROPICAL 48H 25/1800Z...DISSIPATED $$ Forecaster Kelly/Pasch |
