[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 231445
TCDAT5

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.


FORECAST POSITIONS AND MAX WINDS

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
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