538 
 WTNT43 KNHC 120835
 TCDAT3
 
 Hurricane Helene Discussion Number  20
 NWS National Hurricane Center Miami FL       AL082018
 500 AM AST Wed Sep 12 2018
 
 Earlier this morning, Helene looked quite ragged in IR imagery. The
 eye became poorly defined and cloud tops were steadily warming.
 However, beginning around 0500 UTC, a new burst of convection began
 wrapping around the previously open western portion of Helene's
 inner core. Objective and subjective Dvorak current intensity
 estimates range from 77 to 91 kt, and the initial intensity is
 therefore set at 80 kt as a blend of all of these data.
 
 Despite the fact that Helene appears to be on the upswing at the
 moment, the cyclone is still passing over sub-26 deg C waters and
 all of the intensity guidance shows weakening for the next 24 h.
 Beyond that time, there is still some spread among the intensity
 models, though it has decreased since the last advisory. Helene will
 begin interacting with a mid-latitude trough over the north-central
 Atlantic, which will result in an increase in shear over the
 hurricane. However, Helene will also begin to move over warmer
 waters and could get some baroclinic support from the upper-level
 trough. Overall the intensity guidance is a little lower than
 before, and now the NHC intensity forecast is near the middle of the
 intensity guidance envelope.
 
 Once again, no meaningful change has been made to the NHC track
 forecast which continues to closely follow the HFIP Corrected
 Consensus. Helene is moving north-northwestward, and should
 gradually turn northward, and eventually northeastward, as the
 cyclone is steered between a mid-level ridge to the east and the
 aforementioned mid-latitude trough to northwest. The global models
 remain in fairly good agreement on the track of Helene, especially
 through 72-96 h, when Helene is forecast to pass near the Azores,
 and interests in those islands should closely monitor the progress
 of Helene over the next several days.
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  12/0900Z 19.2N  35.7W   80 KT  90 MPH
  12H  12/1800Z 20.7N  36.6W   75 KT  85 MPH
  24H  13/0600Z 22.9N  37.2W   65 KT  75 MPH
  36H  13/1800Z 25.5N  37.3W   55 KT  65 MPH
  48H  14/0600Z 28.9N  36.9W   55 KT  65 MPH
  72H  15/0600Z 36.0N  34.3W   50 KT  60 MPH
  96H  16/0600Z 41.0N  28.5W   50 KT  60 MPH
 120H  17/0600Z 45.5N  19.0W   50 KT  60 MPH
 
 $$
 Forecaster Zelinsky