WTPA45 PHFO 270240
TCDCP5

TROPICAL DEPRESSION HILDA DISCUSSION NUMBER  19
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP112009
500 PM HST WED AUG 26 2009

HILDA STRUGGLED TO MAINTAIN DEEP CONVECTION TODAY AND SINCE THE MID
MORNING FAILED TO KEEP PERSISTENT CONVECTION NEAR THE CENTER.  OVER
THE PAST 3 TO 4 HOURS...THE LOW LEVEL CIRCULATION CENTER BECAME
EXPOSED. ISOLATED THUNDERSTORMS CONTINUE TO FLARE UP AND DOWN NORTH
THROUGH WEST OF CENTER. AN ASCAT PASS AROUND NOON CAUGHT THE
WESTERN HALF OF HILDA AND SHOWED A SMALL AREA OF 25 TO 30 KT WINDS
IN THE NORTHWEST QUADRANT. SAB AND PHFO FIXES CAME IN AT 2.0. THE
JTWC FIX WAS CONSTRAINED TO 2.5.  WITH NO INDICATION OF 35 KT WINDS
AND THE LACK OF PERSISTENT DEEP CONVECTION...HAVE DOWNGRADED HILDA
INTO A DEPRESSION AT 30 KT.

THE INTENSITY FORECAST FOR HILDA HAS BEEN CHALLENGING THROUGHOUT. 
FIRST AND EARLY ON...HILDA MANAGED TO INTENSIFY IN THE FACE OF 15
KT SHEAR...AND THEN WEAKENED WITH LITTLE TO NO SHEAR IN THE PAST 36
HOURS. THE PRESUMED FACTOR IN WEAKENING REMAINS THE INGEST OF
DRY AIR FROM THE NORTH. WITH DRY AIRMASS TO THE NORTH REMAINING IN
PLACE AND SHEAR EXPECTED TO INCREASE OVER THE NEXT 48 HOURS...HAVE
MADE NOTABLE CHANGES TO THE INTENSITY FORECAST. HILDA IS NOW
EXPECTED TO CONTINUE WEAKENING AND BECOME A REMNANT LOW IN 24 TO 36
HOURS THEN DISSIPATE BY 48 HOURS. THE EXPOSED LOW LEVEL CENTER AND
MOVEMENT OF THE DEEP CONVECTION TOWARD THE WEST AS SHOWN IN VISIBLE
SATELLITE TODAY SHOWS SHEAR IS ALREADY TAKING ITS TOLL. WITH THE
EXCEPTION OF HWRF AND SHIPS...THE MAJORITY OF THE INTENSITY
GUIDANCE HAS JUST ABOUT FLAT LINED.
 
HILDA STUBBORNLY CONTINUES TO MOVE SOUTH OF THE FORECAST TRACK AND
IS NOW BELOW 13 DEGREES NORTH. HILDA ALSO APPEARS TO HAVE SLOWED
DOWN SLIGHTLY OVER THE PAST SIX HOURS. AS THE PREVIOUS FORECAST WAS
ALREADY ON THE SOUTHERN HALF OF THE GUIDANCE ENVELOPE...SAW NO
REASON TO MAKE MUCH ADJUSTMENTS. THE LATEST FORECAST HAS NEGLIGIBLE 
CHANGES THROUGH 36 HOURS AND POSITIONS BEYOND WERE REMOVED
DUE TO THE FORECAST DISSIPATION AT 48 HOURS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      27/0300Z 12.9N 151.7W    30 KT
 12HR VT     27/1200Z 12.8N 152.9W    30 KT...DISSIPATING
 24HR VT     28/0000Z 12.7N 154.2W    25 KT...REMNANT LOW
 36HR VT     28/1200Z 12.7N 156.3W    25 KT...REMNANT LOW
 48HR VT     29/0000Z...DISSIPATED
 
$$
FORECASTER TANABE