853 
 WTPZ43 KNHC 120833
 TCDEP3
  
 TROPICAL STORM HECTOR DISCUSSION NUMBER   4
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP082012
 200 AM PDT SUN AUG 12 2012
 
 THE CLOUD PATTERN OF THE STORM IS DOMINATED BY A MASS OF COLD-TOPPED
 CONVECTION NEAR AND TO THE WEST OF THE ESTIMATED CENTER...AND
 CONVECTIVE BANDING FEATURES HAVE BECOME ILL-DEFINED.  USING A BLEND
 OF DVORAK ESTIMATES FROM TAFB AND SAB...THE CURRENT INTENSITY IS
 SET AT 40 KT.  THE RATHER SHARP EASTERN EDGE OF THE CONVECTIVE MASS
 IS HIGHLY SUGGESTIVE OF EASTERLY SHEAR...AND IN FACT THE SHIPS
 MODEL DIAGNOSES THE VERTICAL SHEAR TO BE ON THE ORDER OF 20 KT FOR
 THE NEXT DAY OR SO.  IN 36 TO 48 HOURS THE GLOBAL MODELS SHOW THE
 UPPER-LEVEL ANTICYCLONE NORTH OF HECTOR WEAKENING...RESULTING IN A
 REDUCTION OF THE EASTERLY SHEAR.  THIS WOULD ALLOW FOR SOME
 STRENGTHENING UNTIL ABOUT 72 HOURS.  AFTER THAT TIME... HOWEVER...
 HECTOR SHOULD BE MOVING OVER PROGRESSIVELY COOLER WATERS WHICH
 SHOULD LEAD TO WEAKENING.  THE OFFICIAL INTENSITY FORECAST IS
 SIMILAR TO THE PREVIOUS ONE AND REMAINS A LITTLE HIGHER THAN MOST OF
 THE GUIDANCE.
 
 WITH INFRARED IMAGERY...IT IS DIFFICULT TO LOCATE THE CENTER VERY
 PRECISELY...AND THE INITIAL MOTION IS A RATHER UNCERTAIN 285/10. 
 MUCH OF THE DYNAMICAL GUIDANCE SHOWS A SLOWING OF THE FORWARD SPEED
 AND A TURN TOWARD THE LEFT AS HECTOR APPEARS TO BE INTERACTING WITH
 A BROADER CYCLONIC GYRE OR A TROUGH TO THE SOUTH.  LATER IN THE
 FORECAST PERIOD THIS INFLUENCE IS EXPECTED TO LESSEN...AND THE
 MOTION SHOULD TURN BACK TOWARD THE WEST-NORTHWEST OR NORTHWEST AS
 THE CYCLONE BECOMES STEERED BY THE FLOW TO THE SOUTHWEST OF A
 MID-TROPOSPHERIC HIGH NEAR THE SOUTHWESTERN UNITED STATES.  THE
 OFFICIAL TRACK FORECAST IS NOT MUCH DIFFERENT FROM THE PREVIOUS ONE
 AND ROUGHLY BETWEEN THE LATEST GFS AND ECMWF TRACKS.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  12/0900Z 18.6N 109.4W   40 KT  45 MPH
  12H  12/1800Z 18.7N 110.5W   40 KT  45 MPH
  24H  13/0600Z 18.5N 111.3W   45 KT  50 MPH
  36H  13/1800Z 18.4N 111.8W   45 KT  50 MPH
  48H  14/0600Z 18.5N 112.4W   50 KT  60 MPH
  72H  15/0600Z 19.4N 114.4W   55 KT  65 MPH
  96H  16/0600Z 20.5N 116.0W   50 KT  60 MPH
 120H  17/0600Z 21.5N 118.5W   40 KT  45 MPH
  
 $$
 FORECASTER PASCH