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TROPICAL STORM GASTON DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072016
1100 PM AST TUE AUG 23 2016

Gaston's cloud pattern has a figure-nine appearance, with an
apparent dry slot over the southwest quadrant, and lacks a
well-defined CDO at this time.  The intensity is held at 55 kt in
agreement with subjective and objective Dvorak estimates.  The
system has fairly well-defined upper-level outflow and is expected
to remain in a low-shear environment for the next day or so.
Therefore, the cyclone is likely to intensify into a hurricane in 12
to 24 hours.  In about 36 hours, however, Gaston should encounter
increasing southwesterly shear associated with an upper-tropospheric
trough near 50-55W.  This should at least temporarily halt the
intensification process, and probably cause a little weakening.
The global models indicate that Gaston will pass by the trough in 72
hours, and reintensification should commence around that time.  The
official intensity forecast is near the high end of the guidance
models through 72 hours, and close to the model consensus
thereafter.

The motion continues toward the west-northwest, or 290/15 kt.
Gaston should gradually turn toward the northwest in response to a
break in the subtropical ridge near 60W.  The official track
forecast, which is very similar to the previous one, follows the
latest dynamical model consensus, TVCN.

FORECAST POSITIONS AND MAX WINDS

INIT  24/0300Z 14.7N  37.1W   55 KT  65 MPH
 12H  24/1200Z 15.8N  39.2W   65 KT  75 MPH
 24H  25/0000Z 17.5N  41.7W   70 KT  80 MPH
 36H  25/1200Z 19.5N  44.1W   75 KT  85 MPH
 48H  26/0000Z 22.0N  46.2W   75 KT  85 MPH
 72H  27/0000Z 26.5N  51.0W   70 KT  80 MPH
 96H  28/0000Z 29.5N  54.5W   75 KT  85 MPH
120H  29/0000Z 31.5N  55.0W   85 KT 100 MPH

$$
Forecaster Pasch

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