[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT45 KNHC 222046
TCDAT5

Hurricane Don Discussion Number  35
NWS National Hurricane Center Miami FL       AL052023
500 PM AST Sat Jul 22 2023

Don's cloud pattern continued to become better organized after the
release of the previous advisory with convection wrapping around an
eye in infrared imagery.  Since that time, the cloud tops over the
western semicircle have warmed somewhat, but a 1648 UTC AMSR2
microwave pass showed a well-defined low- to mid-level eye with deep
convection surrounding it.  Subjective Dvorak estimates at 1800 UTC
ranged from T4.0 (65 kt) from TAFB and T3.5 (55 kt) from SAB, with
objective estimates in the 60 to 63 kt range.  Since subjective
estimates have yielded a T4.0 throughout much of the afternoon, the
initial intensity has been raised to 65 kt, making Don a hurricane.

Today's strengthening was the result of the storm passing over the
warmer waters of the Gulf Stream, however it will move north of
those warmer waters later this evening, and Don has likely peaked in
intensity.  Weakening should begin overnight, with a faster rate of
weakening expected Sunday through Monday as Don moves over even
colder waters and the vertical wind shear increases. The cyclone is
expected to become post-tropical by Sunday night, and dissipate by
Monday night or early Tuesday.

Don is moving northward or 005 degrees at 10 kt. The cyclone is
forecast to turn northeastward late tonight as it becomes embedded
within southwesterly flow between a ridge to its east and a broad
trough over eastern Canada.  A northeastward to east-northeastward
motion should then continue until the system dissipates in 2-3 days.
The track guidance is again tightly clustered and no significant
changes to the previous official forecast were required.


FORECAST POSITIONS AND MAX WINDS

INIT  22/2100Z 40.1N  50.0W   65 KT  75 MPH
 12H  23/0600Z 42.0N  49.6W   60 KT  70 MPH
 24H  23/1800Z 44.5N  47.6W   50 KT  60 MPH
 36H  24/0600Z 46.4N  44.5W   40 KT  45 MPH...POST-TROPICAL
 48H  24/1800Z 47.7N  40.4W   30 KT  35 MPH...POST-TROP/REMNT LOW
 60H  25/0600Z...DISSIPATED

$$
Forecaster Brown
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