255 
 WTPZ41 KNHC 020852
 TCDEP1
 
 Hurricane Sergio Discussion Number  12
 NWS National Hurricane Center Miami FL       EP212018
 300 AM MDT Tue Oct 02 2018
 
 Geostationary satellite imagery indicates that Sergio continues to
 strengthen.   The center is located within a fairly symmetric CDO
 with cloud tops of -70 to -80 degrees C.  Earlier microwave data
 showed a well-defined eye and inner core, but a more recent AMSU
 overpass suggests that there has been some slight erosion of the
 eastern portion of the eye, possibly due to some intrusion of dry
 mid-level air.  Dvorak intensity estimates ranged from 75 to 90 kt,
 and the initial intensity has been increased to a possibility
 conservative 75 kt for this advisory.
 
 The intensity forecast remains somewhat uncertain.  Although
 Sergio has developed an inner core and strengthened during the past
 12 hour or so, the dynamical models suggest northeasterly shear
 will increase over the hurricane today.  This is expected to temper
 the intensification somewhat over the next 12-24 hours, however,
 most of the guidance shows at least gradual strengthening during
 the next day or so.  The NHC intensity forecast calls for a gradual
 increase in wind speed over the next 36-48 hours, and is close to
 the IVCN model consensus.  After 72 h, cooler waters and the
 entrainment of drier air is expected to cause gradual weakening.
 
 Sergio is moving slightly south of due west or 265/12 kt.  The
 hurricane is currently located to the south of a mid-level ridge,
 and Sergio should continue westward today.  The global models show
 the western portion of the ridge weakening over the next several
 days, which should cause Sergio to turn west-northwestward, then
 northwestward on Wednesday. By late in the week, another ridge
 is predicted to build to the northwest of Sergio and the hurricane
 is forecast to turn back toward the west.  The overall guidance
 envelope has changed little this cycle, and the new NHC track is
 similar to the previous advisory and close to the various consensus
 aids.
 
 
 FORECAST POSITIONS AND MAX WINDS
 
 INIT  02/0900Z 10.7N 113.2W   75 KT  85 MPH
  12H  02/1800Z 10.9N 114.7W   85 KT 100 MPH
  24H  03/0600Z 11.7N 116.4W   90 KT 105 MPH
  36H  03/1800Z 12.7N 117.8W   95 KT 110 MPH
  48H  04/0600Z 13.8N 119.0W  100 KT 115 MPH
  72H  05/0600Z 15.6N 121.7W  100 KT 115 MPH
  96H  06/0600Z 16.5N 124.6W   90 KT 105 MPH
 120H  07/0600Z 16.7N 127.5W   80 KT  90 MPH
 
 $$
 Forecaster Brown