Official Discussion issued by the National Hurricane Center

Don (AL052023) DATA RELEASED: 7/21/2023 3:00:00 AM UTC

Copy of official data

Tropical Storm Don Discussion Number  28
NWS National Hurricane Center Miami FL       AL052023
300 AM GMT Fri Jul 21 2023

The band of convection noted on the eastern side of Don during the 
previous advisory has wrapped around to the western side of the 
tropical cyclone tonight. However, Don still is struggling to mix 
out the dry air that earlier disrupted its convective structure. 
ASCAT-C at 2339 UTC and ASCAT-B at 0026 UTC nicely captured Don's 
circulation, and both had a peak wind retrieval of 40 kt, a bit 
higher than earlier. However, there have been no changes to the 
subjective Dvorak CI numbers from TAFB and SAB this cycle and so the 
initial intensity remains 45 kt for this advisory. 

Don continues to move west-northwestward at 290/8 kt. The storm is 
being steered by a strong low- to mid-level ridge that should 
gradually first shift northeastward and then eastward of the cyclone 
as a short-wave trough currently over the Great Lakes ejects 
eastward into the Canadian Maritimes over the next few days. This 
synoptic pattern should result in Don turning to the northwest and 
then north over the next 36-48 hours. Afterwards, Don should 
complete recurvature northeast into the higher latitudes as it opens 
up into a trough. The track guidance consensus has stabilized not 
too far off from the prior forecast track, and very few adjustments 
were needed to the official NHC track for this forecast cycle. 

Don's structure appears quite healthy in the low-levels, per earlier 
37 GHz microwave imagery which showed evidence of a closed cyan 
ring. However, the combination of dry mid-level air and marginal 
(24-25 C) sea surface temperatures appear to be keeping deep 
convection (below -50C) in check while it attempts to wrap around 
the center. These factors are likely to limit intensification, and 
little change in strength is forecast over the next 36 h or so. 
Weakening is then forecast to begin by 48 h as Don approaches the 
north wall of the Gulf Stream and encounters a more hostile 
upper-level flow pattern. Most of the global and regional-hurricane 
model guidance show Don ceasing to produce organized convection by 
72 h, and the storm is forecast to become post-tropical at that 
time, followed by dissipation in 96 h. This forecast is in good 
agreement with the consensus aids. 


INIT  21/0300Z 34.8N  44.7W   45 KT  50 MPH
12H  21/1200Z 35.4N  46.1W   45 KT  50 MPH
24H  22/0000Z 36.9N  48.1W   45 KT  50 MPH
36H  22/1200Z 38.8N  49.9W   45 KT  50 MPH
48H  23/0000Z 41.1N  50.9W   40 KT  45 MPH
60H  23/1200Z 43.6N  51.1W   35 KT  40 MPH
72H  24/0000Z 46.2N  49.6W   30 KT  35 MPH...POST-TROPICAL
96H  25/0000Z...DISSIPATED

Forecaster Papin