[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT45 KNHC 200838
TCDAT5

Tropical Storm Don Discussion Number  25
NWS National Hurricane Center Miami FL       AL052023
900 AM GMT Thu Jul 20 2023

Deep convection associated with Don has become a little better
organized since the last advisory, with a curved convective band
currently developing near and to the north of the center.  However,
the various subjective and objective satellite intensity estimates
have not changed significantly, and thus the initial intensity
remains 45 kt.

Conditions appear favorable for some strengthening during the next
18-24 h, and the intensity forecast follows the previous forecast
in bringing the winds up to 50 kt during this time.  After 24 h,
the cyclone will be moving over cooler sea surface temperatures,
and after 72 h the cyclone should move north of the Gulf Stream
into an area where the water temperatures are below 20C.  Based on
this and forecast dry air entrainment, the new intensity forecast
follows the previous forecast in showing Don starting to weaken
around 48 h, then it shows a faster rate of weakening after 72 h.
The cyclone is forecast to degenerate to a post-tropical low with
no convection by 96 h.

The initial motion is now 285/6 kt.  A low to mid-level ridge is
forecast to build north and east of Don during the next 72 h, which
should steer the cyclone west-northwestward, northwestward, and
eventually northward during the next 72 h.  The guidance has
shifted a little more westward after 48 h, and thus the 60 and 72 h
forecast are a bit to the west of the previous track,  However these
points lie to the east of the various consensus models, and some
additional adjustments may be needed on subsequent advisories.
After 72 h, Don is forecast to recurve northeastward along the
southern edge of the mid-latitude westerlies.


FORECAST POSITIONS AND MAX WINDS

INIT  20/0900Z 34.1N  41.6W   45 KT  50 MPH
 12H  20/1800Z 34.4N  42.7W   50 KT  60 MPH
 24H  21/0600Z 35.0N  44.4W   50 KT  60 MPH
 36H  21/1800Z 36.1N  46.3W   50 KT  60 MPH
 48H  22/0600Z 37.7N  48.0W   50 KT  60 MPH
 60H  22/1800Z 39.3N  49.2W   45 KT  50 MPH
 72H  23/0600Z 41.3N  49.7W   45 KT  50 MPH
 96H  24/0600Z 45.0N  47.0W   35 KT  40 MPH...POST-TROPICAL
120H  25/0600Z 47.0N  40.0W   30 KT  35 MPH...POST-TROPICAL

$$
Forecaster Beven
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