130 
 WTNT43 KNHC 121433
 TCDAT3
 
 Hurricane Helene Discussion Number  21
 NWS National Hurricane Center Miami FL       AL082018
 1100 AM AST Wed Sep 12 2018
 
 The eye has become less distinct, but the overall convective pattern
 remains well organized and symmetric. Based on the latest Dvorak
 estimates, the initial intensity is kept at 80 kt. Most of the
 guidance show a significant increase in the shear in 24 hours,
 but the SSTs are not changing much for the next 2 days or so, thus
 gradual weakening is forecast.  After that time, both shear and SSTs
 will become belligerently unfavorable, resulting in additional
 weakening. By the end of the forecast period, Helene should have
 acquired extratropical characteristic.
 
 The hurricane is moving toward the north-northwest or 340 degrees
 at 12 kt, embedded in the southerly flow to the east of the digging
 trough over the central Atlantic.  Since the trough is forecast to
 amplify, Helene will be forced to turn to the north-northeast and
 northeast with an increase in forward speed. The global models
 remain in fairly good agreement on the current forecast track of
 Helene, and they all bring the cyclone near the Azores in 3 or 4
 days. Interests in those islands should closely monitor the progress
 of Helene over the next several days.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  12/1500Z 20.3N  36.5W   80 KT  90 MPH
  12H  13/0000Z 22.0N  37.2W   70 KT  80 MPH
  24H  13/1200Z 24.5N  37.5W   65 KT  75 MPH
  36H  14/0000Z 27.5N  37.2W   60 KT  70 MPH
  48H  14/1200Z 31.0N  36.5W   50 KT  60 MPH
  72H  15/1200Z 37.7N  33.2W   45 KT  50 MPH
  96H  16/1200Z 42.5N  26.0W   45 KT  50 MPH
 120H  17/1200Z 47.5N  17.5W   45 KT  50 MPH...POST-TROP/EXTRATROP
 
 $$
 Forecaster Avila