[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 150231
TCDAT4

Hurricane Margot Discussion Number  31
NWS National Hurricane Center Miami FL       AL142023
300 AM GMT Fri Sep 15 2023


The satellite depiction of Margot has become more ragged this
evening. After a brief increase in convection earlier today, recent
infrared imagery shows that the convective banding has become more
broken as dry air wraps into the system. The system has also crossed
over a tongue of cooler SSTs, which is limiting deep convection.
With what convection remains the cloud tops have been warming the
past few hours. Subjective Dvorak satellite estimates were CI
3.5/4.0 from SAB and TAFB, respectively. Given the satellite
depiction and the current intensity satellite estimates, the initial
intensity is lowered to 65 kt for this advisory.

Margot has started to make the forecasted clockwise loop in the
central Atlantic, with a current estimated motion of 070/3 kt. A
ridge over the north Atlantic is responsible for Margot slowing
down and then starting a clockwise loop which will last the next
few days. The aforementioned ridge will eventually shift eastward
and Margot should then begin to more northeastward towards the end
of the forecast period. While the overall track pattern has come
into better agreement, there remains along-track speed differences,
with the GFS being the fastest and further northeast. No big changes
to the track forecast were made from the previous one, with only
slight adjustments to trend towards the model consensus aids.

Margot is encountering a fairly hostile environment with low
mid-level relative humidity values and moderate wind shear. Margot
has also crossed a cold tongue of SSTs in the central Atlantic, and
given the slow motion it will also cross its own upwelled cooler
wake. Given the unfavorable conditions, the system should continue
to gradually weaken throughout the period, likely becoming a
tropical storm in the next 12-24 h. Margot should become a
post-tropical cyclone at some point early next week. However, model
simulated satellite still depicts bursts of convection from time to
time, and until there is better agreement, the official forecast
keeps the post-tropical extratropical transition at Day 5, although
this could occur sooner.


FORECAST POSITIONS AND MAX WINDS

INIT  15/0300Z 36.9N  38.9W   65 KT  75 MPH
 12H  15/1200Z 36.7N  38.7W   60 KT  70 MPH
 24H  16/0000Z 36.1N  38.8W   60 KT  70 MPH
 36H  16/1200Z 35.6N  39.5W   55 KT  65 MPH
 48H  17/0000Z 35.4N  41.1W   45 KT  50 MPH
 60H  17/1200Z 35.5N  42.5W   45 KT  50 MPH
 72H  18/0000Z 36.5N  43.3W   45 KT  50 MPH
 96H  19/0000Z 39.2N  41.0W   45 KT  50 MPH
120H  20/0000Z 40.1N  35.5W   40 KT  45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Kelly
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