Official Discussion issued by the National Hurricane Center

(AL052023) DATA RELEASED: 7/24/2023 3:00:00 PM UTC

Copy of official data

Post-Tropical Cyclone Don Discussion Number  42
NWS National Hurricane Center Miami FL       AL052023
300 PM GMT Mon Jul 24 2023

Satellite imagery shows that Don lacks sufficient deep convection to 
classify the system as a tropical cyclone, and it is now post 
tropical.  The initial wind speed remains at 40 kt for this 
advisory, based on a recent ASCAT-B scatterometer pass.  Don should 
slowly weaken over the next day or so while moving over cold waters 
and within high vertical wind shear.

The system is moving east-northeastward at about 17 kt, and this
general motion will likely to continue until Don dissipates in
about a day.  Most of the global guidance has post-tropical Don
opening up into a trough and becoming absorbed by a larger
extratropical low over the north Atlantic tomorrow. Very few changes
were made to the previous NHC forecast.

Don has been a very long-lasting tropical cyclone (including
subtropical stages) for the month of July.  Preliminary data
indicate that the storm is the 5th longest-lasting system on record
for the month, just behind Emily of 2005.

This is the last advisory on Don.  Additional information on this
system can be found in High Seas Forecasts issued by the National
Weather Service...under AWIPS header NFDHSFAT1 and WMO header
FZNT01 KWBC, and online at


INIT  24/1500Z 47.6N  40.7W   40 KT  45 MPH...POST-TROPICAL
12H  25/0000Z 48.1N  36.9W   35 KT  40 MPH...POST-TROPICAL
24H  25/1200Z...DISSIPATED

Forecaster Kelly/Pasch