ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
 
Tropical Storm Gaston Discussion Number   6
NWS National Hurricane Center Miami FL       AL082022
Issued by the NWS Weather Prediction Center College Park MD
900 PM GMT Wed Sep 21 2022

There has been little change associated with Gaston during the past 
several hours.  The system continues to produce an area of deep 
convection near the center and exhibits well-defined outflow over 
the western semicircle.  However, drier air is entraining into 
the eastern portion of the circulation.  The Dvorak CI-numbers from 
TAFB and SAB continue to support an initial intensity of 55 kt. 
 
Gaston continues to track northeastward over the north-central
Atlantic, with the latest initial motion estimated to be 045/12 kt.
Although there is no significant change to the forecast reasoning,
there is a considerable amount of model spread in the details of the
future steering pattern.  An amplifying ridge associated with Fiona 
is expected to trap Gaston's circulation late this week and this 
weekend.  This could result in a clockwise loop and an eventual 
turn westward.  The new NHC track forecast is a little to the south 
and faster than the previous one, trending toward the latest 
consensus models. 
 
It appears that the opportunity for strengthening has ended.  A slow 
weakening trend should begin in the next day or so when Gaston moves 
over cooler waters and into a region of drier air and slightly 
stronger westerly vertical wind shear.  An approaching mid-level 
trough should aid in the system's transition to an extratropical 
cyclone in a couple of days or so.  The NHC intensity forecast 
remains near the middle of the guidance envelope.
 
Interests in the Azores should continue to monitor the forecast for
Gaston.  For additional information, see warnings and products
issued by the meteorological service in the Azores.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/2100Z 39.0N  40.0W   55 KT  65 MPH
 12H  22/0600Z 40.0N  37.4W   55 KT  65 MPH
 24H  22/1800Z 40.8N  33.9W   55 KT  65 MPH
 36H  23/0600Z 40.9N  31.2W   50 KT  60 MPH
 48H  23/1800Z 40.4N  30.0W   50 KT  60 MPH
 60H  24/0600Z 39.8N  30.1W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  24/1800Z 39.6N  31.1W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  25/1800Z 40.3N  34.7W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  26/1800Z 41.0N  37.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
 
$$
Forecaster Cangialosi/Wegman/Carbin
NNNN