871 
 WTNT42 KNHC 020237
 TCDAT2
 
 HURRICANE GASTON DISCUSSION NUMBER  42
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072016
 1100 PM AST THU SEP 01 2016
 
 The low-level center of Gaston is becoming exposed in infrared
 satellite imagery, with about 25 kt of westerly shear pushing the
 deep convection out ahead of the cyclone.  Dvorak CI numbers remain
 4.5/77 kt from TAFB and 4.0/65 kt from SAB, while the objective ADT
 has dropped well into tropical storm territory.  The initial winds
 are only lowered to 65 kt to allow for a gradual spin down of the
 circulation, but this estimate could be generous.  Due to
 progressively colder sea surface temperatures and persistent shear,
 continued weakening is forecast.  Gaston could lose its deep
 convection in about 36 hours after it has passed the Azores, and
 that's when it is expected to become post-tropical.  Dissipation is
 still forecast by day 3. The NHC intensity forecast is an update of
 the previous one and most closely follows the LGEM.
 
 Now that Gaston's center is exposed, there is more confidence in
 the initial motion (075/20 kt).  Gaston is expected to move
 eastward or east-northeastward at a slower forward speed near the
 western and central Azores during the next 36 hours.  After that
 time, the shallow remnant low should turn northeastward ahead of an
 approaching cold front.  The track guidance remains in good
 agreement, and the NHC forecast is close to the TVCN multi-model
 consensus.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  02/0300Z 38.3N  36.0W   65 KT  75 MPH
  12H  02/1200Z 38.8N  33.0W   55 KT  65 MPH
  24H  03/0000Z 39.4N  29.8W   45 KT  50 MPH
  36H  03/1200Z 40.6N  27.0W   35 KT  40 MPH...POST-TROPICAL
  48H  04/0000Z 42.7N  23.6W   30 KT  35 MPH...POST-TROP/REMNT LOW
  72H  05/0000Z...DISSIPATED
 
 $$
 Forecaster Berg