WTPA45 PHFO 250250
TCDCP5

TROPICAL STORM HILDA DISCUSSION NUMBER  11
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP112009
500 PM HST MON AUG 24 2009

HILDA CONTINUES TO STRUGGLE UNDER THE INFLUENCE OF NORTHEASTERLY
SHEAR THIS AFTERNOON.  UPPER LEVEL OUTFLOW REMAINS GOOD TO THE
SOUTH BUT RESTRICTED TOWARD THE NORTH DUE TO THE SHEAR. RECENT
IMAGES SUGGEST THAT THE SHEAR MAY BE EASING DUE TO A SLIGHT
NORTHWARD SPREADING OF THE HIGH LEVEL CLOUDS.  MOST OF THE DEEP
CONVECTION REMAINS CONFINED TO A RAINBAND ALONG THE SOUTHERN
SEMICIRCLE WITH PULSING DEEP CONVECTION NEAR THE CENTER.
DVORAK INTENSITY VALUES CAME IN AT 55 KT FROM CPHC...JTWC AND SAB.
CIMSS SATCON AND ADT VALUES CAME IN AT 52 KT AND 39 KT
RESPECTIVELY.  BASED ON A BLEND OF THE SUBJECTIVE AND OBJECTIVE
ESTIMATES ALONG WITH THE OVERALL SATELLITE PRESENTATION...WILL DROP
THE INITIAL INTENSITY TO 50 KT FOR THIS FORECAST PACKAGE.
 
HILDA CONTINUES TO MOVE IN A GENERAL WESTWARD DIRECTION TO THE SOUTH
OF A SUBTROPICAL RIDGE.  THIS MOTION IS EXPECTED TO CONTINUE OVER
THE NEXT DAY THOUGH WITH A DECREASE IN FORWARD SPEED.  AFTER 24
HOURS...GLOBAL MODELS CONTINUE TO DEVELOP AN ANTICYCLONE NORTH OR
NORTHWEST OF THE HAWAIIAN ISLANDS AND A DEEP MID-LATITUDE TROUGH
FAR NORTH-NORTHEAST OF HILDA.  THIS PATTERN SHOULD PUT A
WEST-SOUTHWESTWARD STEERING CURRENT ON THE TROPICAL CYCLONE FROM 24
THROUGH 72 HOURS. BEYOND 72 HOURS...A MID- AND UPPER LEVEL TROUGH
SHOULD RESULT IN A WEST-NORTHWESTWARD TRACK. MOST OF THE DYNAMICAL
OBJECTIVE AIDS...INCLUDING HWRF...GFDL AND TCON ARE IN AGREEMENT
WITH THIS SOLUTION. THE OFFICIAL FORECAST IS IN CLOSE AGREEMENT
WITH THE MODEL CONSENSUS AND A BIT SLOWER THAN THE PREVIOUS
FORECAST TRACK. NOGAPS AND ECMWF CONTINUE TO PRESENT THE NORTHERN
OUTLIER TRACKS...PRESUMABLY DUE TO A SLOWER FORWARD MOTION WHICH
WOULD BUY TIME FOR THE PROJECTED MIDDLE AND UPPER LEVEL TROUGH TO
DEVELOP AND INDUCE A SHARPER NORTHWESTWARD MOTION.  WHILE THE BULK
OF THE OBJECTIVE AIDS AND THE OFFICIAL FORECAST DO NOT REFLECT THIS
SOLUTION...IT IS STILL TOO EARLY TO TELL WHAT WILL ACTUALLY OCCUR.
 
VERTICAL SHEAR HAS BEEN THE INHIBITING FACTOR FOR INTENSITY.
HOWEVER...THE SHEAR APPEARS TO BE RELAXING AND HILDA SHOULD RESUME
INTENSIFICATION. SST VALUES WILL REMAIN MORE THAN ADEQUATE AT 27C
TO 28C.  THE MAIN OBJECTIVE AIDS SHOW BETTER CONSISTENCY THIS TIME
WITH GHMI...HWRF AND SHIPS ALL INDICATING HURRICANE STRENGTH
BETWEEN 48 AND 72 HOURS.  THE FORECAST CALLS FOR HILDA TO REACH
HURRICANE INTENSITY AT AROUND 72 HOURS...AND 75 KT BY 120 HOURS. 
THIS IS CLOSE TO THE INTENSITY CONSENSUS. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      25/0300Z 14.9N 147.1W    50 KT
 12HR VT     25/1200Z 15.0N 148.2W    55 KT
 24HR VT     26/0000Z 14.9N 149.6W    55 KT
 36HR VT     26/1200Z 14.8N 151.0W    60 KT
 48HR VT     27/0000Z 14.5N 152.3W    60 KT
 72HR VT     28/0000Z 14.3N 154.7W    65 KT
 96HR VT     29/0000Z 15.1N 157.5W    70 KT
120HR VT     30/0000Z 16.6N 161.3W    75 KT
 
$$
FORECASTER KODAMA