|
Show Selection: |
| #1144562 (Received by flhurricane at: 4:36 PM 20.Jul.2023) TCDAT5 Tropical Storm Don Discussion Number 27 NWS National Hurricane Center Miami FL AL052023 900 PM GMT Thu Jul 20 2023 A band of deep convection has developed over the eastern portion of Don`s circulation since the previous advisory, however, there has been little overall change in the cyclone`s organization today. The latest subjective Dvorak CI numbers from SAB and TAFB were unchanged from this morning so the initial intensity remains 45 kt. Although that could be a little generous based on the earlier scatterometer data, it is best to hold the intensity steady until the next ASCAT overpass this evening. Recent satellite fixes indicate that Don continues to move west-northwestward (290 degrees) but at a slightly faster forward speed of 9 kt. A strong low- to mid-level ridge that is currently located to the north of Don is forecast to shift eastward during the next 2 to 3 days. This should cause Don to turn northwestward on Friday and then northward ahead of a broad mid-level trough over the western Atlantic later this weekend. After that time, the cyclone is forecast to turn northeastward in the low- to mid-level southwesterly flow ahead of the aforementioned trough. The dynamical model envelope has again shifted to the west and the NHC track forecast has been adjusted accordingly. Marginal sea surface temperatures, moderate shear, and nearby dry mid-level have prevented additional strengthening today. Those conditions are not forecast to change much during the next couple of days and therefore, little overall change in strength is expected during that period. Don is forecast to move north of the Gulf stream and over much cooler waters in 60 to 72 hours, and it is likely to become post-tropical shortly thereafter. The global models show the system becoming an open trough in 4 to 5 days and the official forecast calls for dissipation by that time. FORECAST POSITIONS AND MAX WINDS INIT 20/2100Z 34.7N 43.7W 45 KT 50 MPH 12H 21/0600Z 35.1N 45.1W 45 KT 50 MPH 24H 21/1800Z 36.2N 47.1W 45 KT 50 MPH 36H 22/0600Z 37.8N 49.0W 45 KT 50 MPH 48H 22/1800Z 39.7N 50.4W 45 KT 50 MPH 60H 23/0600Z 42.1N 51.2W 40 KT 45 MPH 72H 23/1800Z 44.6N 50.4W 35 KT 40 MPH 96H 24/1800Z 49.7N 42.4W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 25/1800Z...DISSIPATED $$ Forecaster Brown |
