WTPA45 PHFO 251449
TCDCP5

TROPICAL STORM HILDA DISCUSSION NUMBER  13
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP112009
500 AM HST TUE AUG 25 2009

THE SHEAR ACROSS HILDA HAS DIMINISHED TO LESS THAN 10 KT AND OUTFLOW
OF HIGH CLOUDS LOOKS PRETTY GOOD IN ALL QUADRANTS. ALSO WITH THE
SHEAR ALMOST GONE...DEEP CONVECTION IS NO LONGER RELEGATED TO THE
SOUTHWEST SEMICIRCLE BUT RATHER APPEARS TO BE OVER THE ESTIMATED
LOW LEVEL CENTER. SAB AND JTWC AGAIN HAD A CI NUMBER OF 3.5 WHILE
PHFO STAYED AT 4.0. THE INITIAL INTENSITY OF 50 KT IS BASED ON THE
FIRST TWO AND AN ADT CI OF 3.6.

HILDA WILL CONTINUE TO MOVE TO THE WEST OVER THE NEXT 24 HOURS AS IT
REMAINS IN DEEP LAYER EASTERLIES LOCATED SOUTH OF THE SUBTROPICAL
RIDGE. FROM 24 TO ABOUT 72 HOURS...A MID AND UPPER LEVEL RIDGE IS
FORECAST TO BUILD NORTHWEST AND WEST OF THE MAIN HAWAIIAN ISLANDS
WHICH SHOULD STEER HILDA ON A WEST-SOUTHWEST COURSE. BEYOND 72
HOURS...THE GLOBAL MODELS DIFFER IN SOLUTIONS BUT IN GENERAL DIG AN
UPPER LEVEL TROUGH SOUTHWARD CLOSE TO THE HAWAIIAN ISLANDS. THE
TROUGH SHOULD WEAKEN THE SURFACE RIDGE NORTHWEST OF HILDA...
ALLOWING THE SYSTEM TO ASSUME A WEST-NORTHWEST COURSE. THE FORECAST
TRACK FOLLOWS THIS SCENARIO AND IS JUST NORTH OF A TIGHTLY BUNCHED
GUNA TCON AND TVCN THROUGH 120 HOURS. THE TRACK IS SOUTH OF AND
SLIGHTLY FASTER THAN THE PREVIOUS TRACK.
 
WITH WEAK SHEAR AND SSTS FROM 27C TO 28C...HILDA IS FORECAST TO
GRADUALLY INTENSIFY. THE INTENSITY FORECAST IN FACT STRENGTHENS
HILDA TO A HURRICANE AFTER 48 HOURS AND IS IN CLOSE AGREEMENT WITH
ICON AND IVCN.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      25/1500Z 14.7N 148.9W    50 KT
 12HR VT     26/0000Z 14.5N 150.2W    50 KT
 24HR VT     26/1200Z 14.3N 151.9W    55 KT
 36HR VT     27/0000Z 14.1N 153.3W    55 KT
 48HR VT     27/1200Z 14.0N 154.9W    60 KT
 72HR VT     28/1200Z 14.2N 158.0W    65 KT
 96HR VT     29/1200Z 15.0N 162.0W    70 KT
120HR VT     30/1200Z 16.8N 166.3W    70 KT
 
$$
FORECASTER CRAIG