082 
 WTNT43 KNHC 130848
 TCDAT3
 
 Hurricane Helene Discussion Number  24
 NWS National Hurricane Center Miami FL       AL082018
 500 AM AST Thu Sep 13 2018
 
 Helene's surface circulation has become fully exposed this morning
 with the center decoupled about 110 miles south of edge of the
 remaining deep convection.  Subjective and objective satellite
 intensity estimates have decreased and support lowering the initial
 intensity to 65 kt.
 
 Statistical and global model guidance show the southwesterly shear
 increasing significantly in 12 hours or so, however, the 26 to
 27C sea surface temperatures should govern the weakening trend a
 little.  In 3 days, Helene is forecast to move over much cooler
 waters while the cyclone becomes embedded in the hostile
 mid-latitude upper-level westerlies.  Subsequently, further
 weakening is expected at a faster pace.  By day 4, the large-scale
 models all show Helene acquiring extratropical cyclone
 characteristics as it moves toward Ireland and the United
 Kingdom.  The NHC intensity forecast is similar to the previous
 advisory, and is based primarily on the NOAA-HCCA and the IVCN
 consensus models.
 
 Helene is still moving northward, or 355/12 kt, within the
 deep-layer southerly flow produced by an amplifying mid-Atlantic
 trough to the west of the cyclone.  In 48 hours, Helene is forecast
 to turn north-northeastward followed by a turn toward the northeast
 with an increase in forward motion at the 72 hour period.  The
 guidance suite remains tightly clustered through day 4, with some
 slight spread at day 5, and indicates that Helene will pass near the
 Azores in about 3 days.  Interests in those islands should closely
 monitor the progress of Helene over the next few days.  The official
 forecast is basically an update of the previous one, and lies close
 to the TVCN multi-model consensus through the entire forecast
 period.
 
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  13/0900Z 23.5N  37.3W   65 KT  75 MPH
  12H  13/1800Z 25.7N  37.4W   60 KT  70 MPH
  24H  14/0600Z 29.1N  36.9W   55 KT  65 MPH
  36H  14/1800Z 32.5N  36.2W   55 KT  65 MPH
  48H  15/0600Z 35.8N  34.7W   55 KT  65 MPH
  72H  16/0600Z 40.7N  28.2W   50 KT  60 MPH
  96H  17/0600Z 44.6N  19.5W   50 KT  60 MPH...POST-TROP/EXTRATROP
 120H  18/0600Z 51.1N  10.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 
 $$
 Forecaster Roberts