[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT45 KNHC 181450
TCDAT5

Tropical Storm Don Discussion Number  18
NWS National Hurricane Center Miami FL       AL052023
300 PM GMT Tue Jul 18 2023

Don has struggled to produce deep convection today, despite the
storm moving over warmer waters, with only a few moderate bands on
the eastern side of the circulation.  A scatterometer pass near
1200 UTC showed maximum winds just above 30 kt, and it seems like
the system is vacillating between 30 and 35 kt as an initial wind
speed, based primarily on convective trends.  I don't really want
to be chasing every burst of convection, so the conservative thing
is to wait a little longer before downgrading it to a depression.

The system should not change much in intensity over the next day or
so while it encounters a slightly more conducive (but still
marginal) environment.  It also wouldn't be a surprise if Don became
a depression again in the short-term.  Modest intensification is
forecast later this week while the system encounters warmer SSTs,
higher mid-level moisture, and the shear remains light or moderate.
The new forecast is similar to the previous one, below the model
consensus given the overall mediocre environment for strengthening.

Don has turned south-southeastward at about 8 kt.  The storm is
about halfway through making a large anticyclonic loop over the
central Atlantic, bending around a blocking ridge in the
mid-latitudes.  Don should move more slowly southward overnight and
Wednesday as it sits beneath the ridge, then gradually accelerate
northwestward and northward as it moves around the ridge.  The track
guidance is coming into better agreement on this course,
conveniently converging somewhat on the last NHC track forecast, so
no significant changes were required.



FORECAST POSITIONS AND MAX WINDS

INIT  18/1500Z 35.6N  39.3W   35 KT  40 MPH
 12H  19/0000Z 34.6N  39.0W   35 KT  40 MPH
 24H  19/1200Z 33.9N  39.4W   35 KT  40 MPH
 36H  20/0000Z 33.7N  40.5W   40 KT  45 MPH
 48H  20/1200Z 34.0N  41.7W   40 KT  45 MPH
 60H  21/0000Z 34.7N  43.3W   45 KT  50 MPH
 72H  21/1200Z 35.7N  45.1W   45 KT  50 MPH
 96H  22/1200Z 39.0N  49.3W   45 KT  50 MPH
120H  23/1200Z 44.0N  49.5W   45 KT  50 MPH

$$
Forecaster Blake
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