566 
 WTPA45 PHFO 252051
 TCDCP5
 
 TROPICAL STORM HILDA DISCUSSION NUMBER  14
 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP112009
 1100 AM HST TUE AUG 25 2009
 
 HILDA HAS BEEN STRUGGLING THIS MORNING AND THE MOST RECENT INFRARED
 IMAGES SHOW WARMING CLOUD TOPS OVER THE CENTER AND THE DEEPEST
 CONVECTION CONFINED TO THE SYSTEM/S SOUTHERN QUADRANT. HILDA/S
 PROBLEMS MAY BE DUE TO THE INGESTION OF DRIER AIR FROM THE
 SURROUNDING AIRMASS. THIS IS SUGGESTED BY WATER VAPOR
 IMAGES...SATELLITE SOUNDER PRECIPITABLE WATER DATA AND THE PRESENCE
 OF OUTFLOW BOUNDARIES IN THE EARLY MORNING VISIBLE IMAGES PUSHING
 OUT FROM BENEATH THE HIGH LEVEL CLOUDS. SSMI 37 GHZ DATA FROM 1632
 UTC SHOWED THE CENTER TO BE DISPLACED FARTHER SOUTH THAN PREVIOUS
 POSITIONS. THIS IS SUPPORTED BY LOW CLOUDS LINES IN THE VISIBLE
 IMAGES. AS A RESULT...THE INITIAL POSITION HAS BEEN ADJUSTED SOUTH.
 DVORAK INTENSITY ESTIMATES RANGED FROM 65 KT TO 45 KT. CIMSS 1600
 UTC SATCON CAME IN AT 35 KT. A QUIKSCAT PASS FROM AROUND 1600 UTC
 SHOWED 40 KT WINDS IN THE NORTHWEST QUADRANT. BASED ON A BLEND OF
 THE SUBJECTIVE AND OBJECTIVE ESTIMATES...WILL GO WITH AN INITIAL
 INTENSITY OF 45 KT THOUGH THIS MAY BE A BIT HIGH.
  
 HILDA HAS BEEN MOVING SOUTH OF THE SUBTROPICAL RIDGE.  THE
 ORIENTATION OF THE MID-LEVEL RIDGE HAS RESULTED IN A MORE NORTHERLY
 COMPONENT IN THE STEERING FLOW THUS THE MOTION HAS BEEN TOWARD
 THE WEST-SOUTHWEST. GLOBAL MODELS INDICATE THIS PATTERN SHOULD
 CONTINUE OVER THE NEXT 48 HOURS.  BEYOND 48 HOURS...A MID- AND
 UPPER LEVEL TROUGH IS EXPECTED TO DEVELOP NORTHWEST OF HILDA WHICH
 SHOULD RESULT IN A TURN TOWARD THE WEST-NORTHWEST. OBJECTIVE AIDS
 ARE IN BETTER AGREEMENT THAN YESTERDAY WITH MOST OF THE KEY
 DYNAMICAL MODELS CLUSTERED RELATIVELY TIGHT. NOGAPS IS THE NORTHERN
 OUTLIER BUT HAS A LESS DRASTIC NORTHWEST TURN THAN BEFORE AND KEEPS
 HILDA SOUTHWEST OF THE HAWAIIAN ISLANDS.  THE OFFICIAL FORECAST
 STAYS CLOSE TO THE DYNAMICAL CONSENSUS AND HAS BEEN SHIFTED SOUTH
 FROM THE PREVIOUS FORECAST...MAINLY DUE TO THE SHIFT IN INITIAL
 POSITION.
  
 THE INTENSITY FORECAST IS PROBLEMATIC. ASIDE FROM POSSIBLE DRY AIR
 IMPACTS...HILDA IS IN A MILD SHEAR ENVIRONMENT WITH MORE THAN
 ADEQUATE SST/S. IF THE DRY AIR INFLUENCE EASES...STRENGTHENING
 SHOULD OCCUR AT LEAST THROUGH 72 HOURS. BEYOND 72 HOURS...GLOBAL
 MODELS INDICATE AN INCREASE IN VERTICAL SHEAR WHICH SHOULD WEAKEN
 HILDA. SHIPS...HWRF AND GHMI ALL INDICATE ADDITIONAL STRENGTHENING.
 THUS...THE KEY UNCERTAINTIES INCLUDE THE CONTINUED INFLUENCE OF DRY
 AIR AND THE STRENGTH OF VERTICAL SHEAR BEYOND DAY 3.  FOR NOW...THE
 OFFICIAL FORECAST CALLS FOR SLIGHT WEAKENING OVER THE NEXT 24 HOURS
 FOLLOWED BY STRENGTHENING TO 72 HOURS. WEAKENING IS FORECAST BEYOND
 72 HOURS DUE TO SHEAR EFFECTS.  NEEDLESS TO SAY...THERE IS NOT A
 LOT OF CONFIDENCE IN THIS INTENSITY FORECAST. 
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      25/2100Z 14.1N 149.1W    45 KT
  12HR VT     26/0600Z 13.8N 150.3W    40 KT
  24HR VT     26/1800Z 13.3N 151.9W    40 KT
  36HR VT     27/0600Z 13.0N 153.5W    45 KT
  48HR VT     27/1800Z 13.0N 155.1W    50 KT
  72HR VT     28/1800Z 13.6N 158.8W    60 KT
  96HR VT     29/1800Z 14.5N 163.0W    60 KT
 120HR VT     30/1800Z 16.1N 167.3W    55 KT
  
 $$
 FORECASTER KODAMA