843 
 WTPZ43 KNHC 211432
 TCDEP3
 HURRICANE HILARY DISCUSSION NUMBER   9
 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
 8 AM PDT SUN AUG 21 2005
  
 TWO MICROWAVE PASSES...A TRMM PASS AT 0950Z AND AN AQUA PASS AT
 0907Z...SUGGEST THAT HILARY MAY NOT BE QUIRE AS WELL ORGANIZED AS
 IT WAS OVERNIGHT.  THE TRMM PASS IN PARTICULAR SHOWS AN EROSION OF
 THE BANDING OR EYEWALL-LOOKING FEATURE WITH A CENTER NORTH OF OUR
 PREVIOUS TRACK.  DVORAK CLASSIFICATIONS...WHICH ARE UNCHANGED FROM
 6 HOURS AGO...ARE UNCERTAIN DUE TO QUESTIONS ABOUR THE CENTER
 LOCATION. THE ADVISORY INTENSITY WILL REMAIN 70 KT PENDING VISIBLE
 IMAGERY...AND HOPEFULLY SOME MORE CLARITY ABOUT THE STRUCTURE OF
 THE CYCLONE. HILARY IS MAINTAINING VERY COLD CONVECTION AT THIS
 TIME AND HAS A LARGE ENVELOPE OF MOISTURE. BOTH THE SHIPS AND GFDL
 GUIDANCE SUGGEST ADDITIONAL STRENGTHENING IS LIKELY BEFORE HILARY
 REACHES COOLER WATERS IN ABOUT 48 HOURS. THE OFFICIAL FORECAST
 DIFFERS FROM THE PREVIOUS ADVISORY WITH A FASTER DECAY OVER THE
 COLD WATER...MORE IN LINE WITH THE GFDL GUIDANCE.
 
 THE MICROWAVE PASSES REQUIRE A NORTHWARD ADJUSTMENT IN THE PRIOR
 TRACK...WITH AN INITIAL MOTION ESTIMATE OF 295/11.  HILARY IS SOUTH
 OF A MINOR WEAKNESS IN THE SUBTROPICAL RIDGE...BUT WILL SHORTLY
 BYPASS THIS WEAKNESS.  MODEL GUIDANCE HAS BEEN TOO FAST WITH THE
 FORWARD SPEED OF HILARY AND STILL APPEARS TO BE INCONSISTENT WITH
 THE PRESENT ESTIMATE OF 11 KT.  A MORE SIGNIFICANT EROSION OF THE
 RIDGE IS EXPECTED WITHIN ABOUT 48 HOURS AS A MID-LEVEL TROUGH IS
 FORECAST TO BECOME ESTABLISHED OVER SOUTHERN CALIFORNIA IN ABOUT 48
 HOURS.  THIS PATTERN SHOULD ALLOW FOR A TEMPORARY INCREASE IN
 SPEED OVER THE NEXT 24 HOURS...FOLLOWED BY A SLOWING OF THE MOTION
 THEREAFTER.  THE OFFICIAL FORECAST REMAINS SLOWER THAN MOST OF THE
 DYNAMICAL GUIDANCE AND IS ALSO SOMEWHAT ON THE RIGHT SIDE OF A
 FAIRLY NARROW GUIDANCE ENVELOPE.  
  
 RAINBANDS PRODUCING OCCASIONAL GUSTY WINDS AND LOCALLY HEAVY
 RAINFALL ARE AFFECTING PORTIONS OF THE SOUTHWESTERN COAST OF MEXICO
 WEST OF ACAPULCO.  CONDITIONS THERE SHOULD GRADUALLY IMPROVE AS
 HILARY MOVES AWAY FROM THE COAST DURING THE NEXT DAY OR SO.
  
 FORECASTER FRANKLIN
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      21/1500Z 15.6N 106.1W    70 KT
  12HR VT     22/0000Z 16.4N 107.9W    80 KT
  24HR VT     22/1200Z 17.3N 110.4W    85 KT
  36HR VT     23/0000Z 18.1N 112.5W    90 KT
  48HR VT     23/1200Z 18.8N 114.2W    90 KT
  72HR VT     24/1200Z 20.0N 116.5W    75 KT
  96HR VT     25/1200Z 21.0N 118.5W    55 KT
 120HR VT     26/1200Z 22.5N 120.5W    40 KT
  
  
 $$