[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 080836
TCDAT4

Tropical Storm Margot Discussion Number   4
NWS National Hurricane Center Miami FL       AL142023
500 AM AST Fri Sep 08 2023

Deep convection has been gradually increasing near and to the north
of the center of Margot during the past few hours.  The satellite
intensity estimates range from 30 to 38 kt, and based on that data,
the initial wind speed is held at 35 kt.

Margot is moving to the west-northwest at about 14 kt on the
southwest side of a mid-level ridge.  The storm is expected to
gradually turn to the northwest and then the north as it moves
toward a weakness in the ridge induced by a mid- to upper-level low
over the central subtropical Atlantic.  The models are in fairly
good agreement, but there are some differences on where and when
Margot makes the northward turn.  The NHC track forecast is similar
to the previous one and near the middle of the guidance envelope.

Global models show Margot strengthening for unconventional reasons.
While there are sufficiently warm ocean water along the forecast
track, deep-layer vertical wind shear is expected to be strong to
moderate as the storm nears an upper-level low pressure.  Typically,
increased shear would lead to a weakening cyclone, but Margot could
be positioned beneath an area of diffluence leading to increased
convection and therefore, strengthening.  The NHC intensity forecast
is similar to the previous one and near the IVCN and HCCA consensus
models.

FORECAST POSITIONS AND MAX WINDS

INIT  08/0900Z 17.4N  30.8W   35 KT  40 MPH
 12H  08/1800Z 18.2N  33.1W   40 KT  45 MPH
 24H  09/0600Z 19.4N  35.7W   45 KT  50 MPH
 36H  09/1800Z 20.6N  37.8W   50 KT  60 MPH
 48H  10/0600Z 21.9N  39.5W   55 KT  65 MPH
 60H  10/1800Z 23.5N  40.5W   60 KT  70 MPH
 72H  11/0600Z 25.2N  41.4W   65 KT  75 MPH
 96H  12/0600Z 28.3N  42.5W   75 KT  85 MPH
120H  13/0600Z 31.4N  43.1W   80 KT  90 MPH

$$
Forecaster Bucci/Cangialosi
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