[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT43 KNHC 240236
TCDAT3

Tropical Storm Gaston Discussion Number  15
NWS National Hurricane Center Miami FL       AL082022
300 AM GMT Sat Sep 24 2022

Gaston continues to decline. Its associated deep convection has been
stripped away by strong northwesterly vertical wind shear, and the
cyclone now consists of a swirl of mainly low-level clouds with
embedded squalls. The initial intensity has been lowered to 45 kt
based on the latest Dvorak CI value from TAFB.

The storm has made its anticipated turn to the southwest and is now
moving at 220/7 kt. A building ridge to the north of Gaston should
turn the cyclone westward later today, and this motion is expected
to continue until the system dissipates late in the forecast
period. The latest NHC forecast track is little changed from the
previous one. On this track, Gaston will move near or over the
central and western Azores today.

Dry air, relatively cool SSTs of 24-25 degrees C, and persistent
strong vertical wind shear should cause Gaston to struggle to
maintain persistent organized deep convection. Therefore, further
weakening is anticipated, and the cyclone is forecast to become
post-tropical by tonight, if not sooner. The latest NHC intensity
forecast was lowered slightly from the previous one and is close to
the various multi-model consensus intensities.

Key Messages:

1. Tropical storm conditions are expected over portions of the
western and central Azores today.

2. Gaston is expected to produce heavy rainfall over the western and
central Azores today. This rainfall may result in landslides and
areas of flooding.


FORECAST POSITIONS AND MAX WINDS

INIT  24/0300Z 38.9N  29.5W   50 KT  60 MPH
 12H  24/1200Z 38.4N  30.5W   45 KT  50 MPH
 24H  25/0000Z 38.5N  32.4W   40 KT  45 MPH...POST-TROPICAL
 36H  25/1200Z 38.7N  35.0W   35 KT  40 MPH...POST-TROPICAL
 48H  26/0000Z 38.7N  36.8W   35 KT  40 MPH...POST-TROPICAL
 60H  26/1200Z 38.6N  38.6W   35 KT  40 MPH...POST-TROPICAL
 72H  27/0000Z 38.3N  40.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  28/0000Z 37.4N  44.9W   30 KT  35 MPH...POST-TROP/REMNT LOW
120H  29/0000Z...DISSIPATED

$$
Forecaster Latto
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