Official Discussion issued by the National Hurricane Center

Don (AL052023) DATA RELEASED: 7/23/2023 3:00:00 PM UTC

Copy of official data

Tropical Storm Don Discussion Number  38
NWS National Hurricane Center Miami FL       AL052023
1100 AM AST Sun Jul 23 2023

Tropical Storm Don continues to move north-northeast over cooling 
sea surface temperatures. Visible and infrared satellite imagery 
still show a well-defined center, with a convective band mainly 
concentrated on the northern and eastern side of the system. The  
subjective Dvorak satellite estimates for this advisory were steady 
from TAFB at T3.5/55 kt, with SAB coming in a little lower. Given 
that there is still a well-defined center, and the aforementioned 
convective band, the initial intensity for this advisory remains 
at 55 kt. 

Don should begin to rapidly weaken as it moves over very cool 
waters with increasing vertical wind shear. Simulated satellite 
imagery from both the GFS and ECMWF models suggest that it should 
lose any remaining deep convection within 24 hours and become a 
post-tropical cyclone.  The intensity forecast remains similar to 
the previous forecast, with Don dissipating in 48 hours.

The system is moving north-northeast, at 14 kt.  Don will 
begin to increase forward speed to the northeast later today and 
east-northeast tomorrow due to the steering flow around the 
northern side of the subtropical ridge.  Guidance remains tightly 
clustered around the previous forecast, and there were very little 
changes made this advisory.

The storm is moving up the list of longest-lasting tropical cyclones 
on record for July (including subtropical stages). Preliminarily, 
Don is tied for 10th, and the cyclone could make the top 5 
longest-lasting for July if it lasts through early Monday.


INIT  23/1500Z 43.9N  47.8W   55 KT  65 MPH
12H  24/0000Z 45.5N  45.8W   45 KT  50 MPH
24H  24/1200Z 47.1N  42.0W   35 KT  40 MPH...POST-TROPICAL
36H  25/0000Z 48.3N  37.5W   30 KT  35 MPH...POST-TROPICAL
48H  25/1200Z...DISSIPATED

Forecaster Kelly/Pasch