Tropical Storm Gaston Forecast Discussion Number 11

By | September 23, 2022

000
WTNT43 KNHC 230237
TCDAT3

Tropical Storm Gaston Discussion Number  11
NWS National Hurricane Center Miami FL       AL082022
300 AM GMT Fri Sep 23 2022

Gaston's cloud pattern is showing signs of disruption by westerly 
shear with the center located near the western edge of the main 
area of convection.  This was confirmed by a recent scatterometer 
overpass, which showed that the intensity was, somewhat 
surprisingly, still near 55 kt.  This intensity is also in 
agreement with a Dvorak classification from TAFB, and so the 
advisory's initial wind speed is held at that value.

The storm has continued to slow its forward speed, with the latest 
initial motion estimated to be eastward at around 10 kt.  
During the next day or so, Gaston is expected to move on a 
clockwise loop along the southern side of a blocking mid-level 
ridge.  The official track forecast follows the multi-model 
consensus prediction.  This is fairly close to the previous NHC 
forecast, except shifted a little northward in the latter part of 
the period.

Gaston is expected to remain in an environment of dry air, over 
relatively cool SSTs, and under the influence of strong westerly 
shear for the next couple of days.  These factors should lead to 
gradual weakening and loss of tropical characteristics in 48 hours 
or so.  The official intensity forecast is similar to the previous 
one and is close to the latest Decay-SHIPS prediction.


Key Messages:

1. Tropical storm conditions are occurring over portions of the 
western Azores, and will likely spread to the central Azores later 
today.

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


FORECAST POSITIONS AND MAX WINDS

INIT  23/0300Z 41.0N  31.0W   55 KT  65 MPH
 12H  23/1200Z 40.4N  29.4W   55 KT  65 MPH
 24H  24/0000Z 39.3N  29.3W   50 KT  60 MPH
 36H  24/1200Z 38.7N  30.4W   50 KT  60 MPH
 48H  25/0000Z 38.9N  32.3W   50 KT  60 MPH...POST-TROPICAL
 60H  25/1200Z 39.4N  34.4W   45 KT  50 MPH...POST-TROPICAL
 72H  26/0000Z 39.8N  36.4W   40 KT  45 MPH...POST-TROPICAL
 96H  27/0000Z 40.9N  38.0W   35 KT  40 MPH...POST-TROPICAL
120H  28/0000Z 41.5N  39.0W   35 KT  40 MPH...POST-TROPICAL

$$
Forecaster Pasch

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