769 
 WTPZ44 KNHC 070831
 TCDEP4
 TROPICAL STORM HERNAN DISCUSSION NUMBER   3
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP092008
 200 AM PDT THU AUG 07 2008
  
 HERNAN'S CLOUD PATTERN CONTINUES TO GRADUALLY INCREASE IN
 ORGANIZATION.  THE CENTER IS ESTIMATED TO BE NEAR THE NORTHEASTERN
 EDGE OF A NEAR-CENTRAL REGION OF VERY COLD-TOPPED CONVECTION...AND 
 THIS HAS BEEN CONFIRMED BY MICROWAVE IMAGERY.  UPPER-LEVEL OUTFLOW
 IS FAIRLY PRONOUNCED OVER THE WESTERN SEMICIRCLE OF THE STORM BUT
 IS IMPEDED ON THE EASTERN SIDE.  CURRENT INTENSITY IS SET AT 45 KT
 BASED ON THE LATEST DVORAK ESTIMATES FROM TAFB AND SAB.  EAST-
 NORTHEASTERLY VERTICAL SHEAR CONTINUES TO HAVE SOME IMPACT... 
 HOWEVER THE SHIPS MODEL INDICATES SOME RELAXATION OF THE SHEAR
 WITHIN THE NEXT DAY OR TWO.  THEREFORE THE ENVIRONMENT SHOULD BE
 AMENABLE FOR GRADUAL STRENGTHENING IN THE NEAR FUTURE.  THE
 OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ONE AND IS
 ON THE HIGH SIDE OF THE VARIOUS OBJECTIVE INTENSITY FORECAST
 TECHNIQUES.  AFTER ABOUT 48 HOURS...HERNAN SHOULD BEGIN TO PASS
 OVER COOLER WATERS SO A GRADUAL DECLINE IN STRENGTH IS FORECAST TO
 COMMENCE AT THAT TIME.
 
 INITIAL MOTION IS AROUND 295/12.  A MID-TROPOSPHERIC RIDGE TO THE
 NORTH AND NORTHEAST OF HERNAN SHOULD PERSIST OVER THE NEXT COUPLE
 OF DAYS.  LATER IN THE PERIOD...HERNAN IS LIKELY TO BE NEARING THE
 WESTERN PERIPHERY OF THE RIDGE.  HOWEVER BY THAT TIME...THE CYCLONE
 WILL BE WEAKENING AND BECOMING SHALLOWER...AND BEING MOVED MORE BY
 LOW-LEVEL EASTERLIES.  THEREFORE A MORE WESTWARD MOTION IS
 INDICATED IN 4 TO 5 DAYS.  THE OFFICIAL FORECAST TRACK IS SIMILAR
 TO BUT A LITTLE FASTER THAN THE PREVIOUS NHC TRACK.  THIS IS FAIRLY
 CLOSE TO THE DYNAMICAL MODEL CONSENSUS.  THE GFDL MODEL IS AN
 OUTLIER AS IT SHOWS A MORE NORTHWESTWARD TRACK THAN THE REST OF THE
 MODEL SUITE.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      07/0900Z 14.5N 114.0W    45 KT
  12HR VT     07/1800Z 15.1N 115.5W    50 KT
  24HR VT     08/0600Z 15.8N 117.5W    55 KT
  36HR VT     08/1800Z 16.5N 119.4W    65 KT
  48HR VT     09/0600Z 17.2N 121.4W    65 KT
  72HR VT     10/0600Z 18.5N 125.0W    55 KT
  96HR VT     11/0600Z 19.0N 128.0W    40 KT
 120HR VT     12/0600Z 19.5N 131.0W    25 KT...REMNANT LOW
  
 $$
 FORECASTER PASCH