WTPA44 PHFO 200255 TCDCP4 TROPICAL DEPRESSION GUILLERMO DISCUSSION NUMBER 32 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP102009 500 PM HST WED AUG 19 2009 ISOLATED THUNDERSTORM CELLS HAVE BEEN DEVELOPING AND DISSIPATING ALONG THE NORTHERN SEMICIRCLE OF GUILLERMO/S WEAKENING CIRCULATION OVER THE PAST 12 TO 24 HOURS...BUT DEEP CONVECTION HAS NOT BEEN ABLE TO PERSIST NEAR THE CENTER...DUE TO VERTICAL WIND SHEAR. VISIBLE SATELLITE IMAGERY SHOWS THAT THE EXPOSED LOW LEVEL CIRCULATION CENTER IS BECOMING INCREASINGLY LESS DEFINED...AND DVORAK CURRENT INTENSITY ESTIMATES FROM PHFO AND PGTW ARE 1.5 WHILE SAB DEEMS THE SYSTEM TOO WEAK TO CLASSIFY. THE INITIAL MOTION IS SIMILAR TO THAT IN THE PREVIOUS ADVISORY... 315/13. WITH GUILLERMO BECOMING A SHALLOW SYSTEM...THE PRIMARY STEERING INFLUENCE IN THE SHORT TERM WILL BE A SURFACE HIGH CENTERED NORTHEAST OF THE SYSTEM THAT WILL MAINTAIN THE CURRENT NORTHWEST MOTION OVER THE NEXT 24 HOURS OR SO. AS THE HIGH WEAKENS AND SHIFTS SOUTHEAST IN 24 TO 48 HOURS...A TURN TO THE NORTH IS ANTICIPATED...ALTHOUGH A NEW HIGH BUILDING FAR NORTH OF THE SYSTEM MAY SLOW THE DEGENERATING SYSTEM/S FORWARD MOTION. THIS TRACK FORECAST FOLLOWS RECENT GUIDANCE TRENDS...IS TO THE RIGHT OF THE PREVIOUS ADVISORY...AND TAKES THE SYSTEM OVER COOLER SSTS. AN UPPER LOW IS CENTERED ABOUT 550 MILES SOUTHWEST OF GUILLERMO... AND IS PROVIDING SIGNIFICANT SOUTHERLY SHEAR OVER THE SYSTEM. WITH THE LOW NEARLY STATIONARY AND GUILLERMO TREKKING NORTHWESTWARD... THE SYSTEM WILL BE APPROACHING A COL IN THE FLOW ALOFT OVER THE NEXT 12 HOURS. A BRIEF RELAXATION OF THE SHEAR WILL LIKELY ALLOW GUILLERMO TO MAINTAIN THE SPORADIC SHORT-LIVED THUNDERSTORMS WITHIN IT/S NORTHERN SEMICIRCLE OVERNIGHT. THIS COL WILL BE BREAKING DOWN WITHIN 12 TO 24 HOURS HOWEVER...AS A SHARPENING MID-LATITUDE TROUGH ABOUT 650 MILES TO THE NORTHWEST DIGS SOUTHEASTWARD. THIS IS EXPECTED TO ONCE AGAIN BRING SIGNIFICANT SOUTHERLY SHEAR OVER THE SYSTEM...AND PRECLUDE ANY CHANCE OF REGENERATION...AND THIS WILL BE THE LAST ADVISORY FROM THE CENTRAL PACIFIC HURRICANE CENTER. FORECAST POSITIONS AND MAX WINDS INITIAL 20/0300Z 31.7N 157.0W 30 KT...DISSIPATING 12HR VT 20/1200Z 33.0N 158.3W 25 KT...REMNANT LOW 24HR VT 21/0000Z 34.7N 158.9W 25 KT...REMNANT LOW 36HR VT 21/1200Z 36.5N 159.1W 25 KT...REMNANT LOW 48HR VT 22/0000Z...DISSIPATED $$ FORECASTER BIRCHARD