[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 151454
TCDAT4

Tropical Storm Margot Discussion Number  33
NWS National Hurricane Center Miami FL       AL142023
300 PM GMT Fri Sep 15 2023

Margot continues to produce small bursts of convection near the
estimated low-level center location.  Microwave imagery from 0923
UTC showed some fragmented curved bands in the northeastern quadrant
of the storm.  Around 1200 UTC, satellite-derived surface winds
measured the eastern portion of the circulation and revealed peak
winds of 44 kt and a significant expansion of tropical-storm-force
winds to the north.  Based on these data, and subjective and
objective satellite estimates, the intensity is lowered to a
possibly generous 55 kt.

The tropical storm is drifting southeastward (135/4 kt) around a
building mid-level ridge over the northern Atlantic.  Margot is
expected to move in a clockwise loop around the ridge during the
next couple of days or so.  The latest NHC forecast shows a slightly
broader loop that lies between the previous forecast and the various
multi-model consensus aids.  By Monday, Margot should turn northward
and then eastward as it moves around the periphery of the ridge.
The model guidance at days 4 and 5 has a large spread in the
along-track position (the forward speed) of Margot and therefore,
the track forecast has greater-than-average uncertainty.  The
official prediction lies between the previous forecast and the
simple consensus aids at those times.

Margot is expected to continue to gradually weaken during the next
couple of days as the vertical wind shear increases and the cyclone
moves into an increasingly dry and stable airmass.  Simulated
satellite imagery from global models shows periodic bursts of
convection through day 4, and the storm is expected to become
extratropical by the end of the forecast period.  While the official
forecast shows Margot's intensity holding steady between 48-96 h,
some minor fluctuations are possible during this time.

FORECAST POSITIONS AND MAX WINDS

INIT  15/1500Z 36.3N  38.2W   55 KT  65 MPH
 12H  16/0000Z 35.8N  38.2W   50 KT  60 MPH
 24H  16/1200Z 35.1N  39.0W   50 KT  60 MPH
 36H  17/0000Z 34.6N  40.5W   45 KT  50 MPH
 48H  17/1200Z 34.8N  42.0W   40 KT  45 MPH
 60H  18/0000Z 35.6N  43.0W   40 KT  45 MPH
 72H  18/1200Z 37.0N  42.6W   40 KT  45 MPH
 96H  19/1200Z 39.5N  38.0W   40 KT  45 MPH
120H  20/1200Z 39.6N  32.0W   35 KT  40 MPH...POST-TROP/EXTRATROP

$$
Forecaster Bucci
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