892 
 WTPZ45 KNHC 261438
 TCDEP5
 
 Hurricane Rosa Discussion Number   6
 NWS National Hurricane Center Miami FL       EP202018
 900 AM MDT Wed Sep 26 2018
 
 Rosa is undergoing rapid intensification.  Rosa's inner core has
 quickly consolidated, indicated by a 1134 UTC SSMI/S image that
 showed a solid mid-level ring with a strong well-developed banding
 feature in the south semicircle.  The lower frequency image from
 the pass indicated a small break in the north portion, probably due
 to the drier air and northeasterly shear that had been inhibiting
 the cyclone's cloud pattern last night.  Based on the conventional
 and microwave imagery presentation, the initial intensity is raised
 to 65 kt.
 
 Rosa should continue on this fast strengthening trend during the
 next 12 hours or so.  Afterward, further intensification, at a
 slower pace, is expected during the next couple of days.  Through
 the remaining portion of the forecast, gradual weakening is expected
 as a result of decreasing sea surface temperatures, increasing
 southwesterly vertical shear, and an invading stable, more drier,
 marine layer air mass.
 
 The initial motion is estimated to be west-northwestward, or 290/9
 kt, within the easterly mid-tropospheric flow produced by a
 ridge to the north of the hurricane.  Around mid-period, the
 large-scale models show a weakness developing the in the
 aforementioned ridge in response to a mid-latitude trough
 approaching the southwest U.S. and Baja California peninsula.  As a
 result of this synoptic pattern change, Rose should move
 northwestward Saturday and then north-northwestward Sunday.  The
 large along and cross-track spread recognized in the guidance 24
 hours ago has decreased significantly, increasing the forecast
 confidence some beyond 48 hours.  The NHC forecast is fairly close
 to the previous one, and is based primarily on the multi-model
 consensus.
 
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  26/1500Z 16.1N 111.4W   65 KT  75 MPH
  12H  27/0000Z 16.4N 112.7W   90 KT 105 MPH
  24H  27/1200Z 16.6N 114.6W  100 KT 115 MPH
  36H  28/0000Z 16.8N 116.2W  105 KT 120 MPH
  48H  28/1200Z 17.3N 117.5W  110 KT 125 MPH
  72H  29/1200Z 19.2N 119.5W  105 KT 120 MPH
  96H  30/1200Z 22.0N 120.2W   85 KT 100 MPH
 120H  01/1200Z 24.9N 119.0W   60 KT  70 MPH
 
 $$
 Forecaster Roberts