Official Discussion issued by the National Hurricane Center

Don (AL052023) DATA RELEASED: 7/17/2023 3:00:00 PM UTC

Copy of official data

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.  


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