WTPA42 PHFO 140250 TCDCP2 HURRICANE FLOSSIE DISCUSSION NUMBER 22 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP092007 500 PM HST MON AUG 13 2007 IT APPEARS THAT HURRICANE FLOSSIE IS BEGINNING TO FEEL THE EFFECTS OF SLIGHTLY COOLER OCEAN TEMPERATURES AND INCREASING SOUTHERLY SHEAR. WHILE OUTFLOW REMAINS GOOD TO THE NORTH...OUTFLOW APPEARS TO BE HAMPERED TO THE SOUTH AND WE ARE BEGINNING TO SEE WEAKENING ALONG THE SOUTHERN FLANK OF THE EYEWALL. CONVECTIVE CLOUD TOPS HAVE WARMED OVER THE PAST SIX HOURS AND AIRCRAFT OBSERVATIONS SHOWED AN EXTRAPOLATED SURFACE WIND OF 106 KT AT 0115Z AS WELL AS AN OPEN EYEWALL ALONG THE SOUTHEAST FLANK. THIS IS IN LINE WITH CI VALUES OF 5.5...102 KT...FROM CPHC...JTWC AND SAB BETWEEN 2330Z AND 0000Z. WE WILL INITIALIZE FLOSSIE AT 105 KT FOR THIS RUN...KEEPING THIS SYSTEM AS A SAFFIR-SIMPSON CATEGORY 3 HURRICANE. CONSENSUS TRACK GUIDANCE REMAINS PACKED THROUGH 24 HOURS...BUT BEGINS TO DIVERGE SHARPLY AFTERWARDS...WITH CONB SIGNIFICANTLY RIGHT OF THE OLD TRACK BEYOND 48 HOURS. BAMD REMAINS THE RIGHT OUTLIER. THE NEW FORECAST TRACK...SITUATED ALONG THE NORTHERN EDGE OF THE CONSENSUS ENVELOPE THROUGH 24 HOURS...LIES ALONG THE OLD TRACK THROUGH 48 HOURS...THEN GRADUALLY DEVIATES TO THE RIGHT AT TAU 72...96 AND 120. THE RESULT IS AN ALMOST STRAIGHT LINE TRACK HEADING TOWARDS THE WEST NORTHWEST. THIS TRACK MODIFICATION DOES NOT BECOME SIGNIFICANT UNTIL FLOSSIE PASSES WEST OF 160W...BEYOND THE REALM OF THE MAIN HAWAIIAN ISLANDS. THIS TRACK DOES INCREASE THE RISK FOR THE NORTHWESTERN HAWAIIAN ISLANDS BEYOND KAUAI. WE FORECAST FLOSSIE WILL GRADUALLY WEAKEN THROUGH 120 HOURS WITH THE ACCUMULATING EFFECTS OF OCEAN COOLING AND INCREASING SHEAR...DROPPING BELOW HURRICANE STRENGTH AT 120 HOURS. SCATTEROMETER AND AIRCRAFT OBSERVATIONS SHOW THE 120 NM TROPICAL STORM STRENGTH WIND RADIUS REMAINS VALID WITHIN THE NORTHWEST AND NORTHEAST QUADRANTS. THIS RADIUS WILL REACH THE BIG ISLAND AS FLOSSIE PASSES TO THE SOUTH...SO A TROPICAL STORM WARNING REMAINS IN EFFECT FOR THE BIG ISLAND...AS WELL AS A HURRICANE WATCH. WITH THE CURRENT FORECAST TRACK...THE ISLANDS FROM MAUI COUNTY TO KAUAI COUNTY ARE NOT EXPECTED TO REQUIRE ANY TYPES OF WATCHES. HOWEVER...ANY SIGNIFICANT DEVIATION OF THE TRACK TOWARD THE NORTH MIGHT RESULT IN WATCHES OR WARNINGS FOR ADDITIONAL AREAS IN THE HAWAIIAN ISLANDS. FORECAST POSITIONS AND MAX WINDS INITIAL 14/0300Z 15.9N 152.0W 105 KT 12HR VT 14/1200Z 16.6N 153.8W 105 KT 24HR VT 15/0000Z 17.6N 156.2W 100 KT 36HR VT 15/1200Z 18.5N 158.5W 95 KT 48HR VT 16/0000Z 19.4N 160.9W 90 KT 72HR VT 17/0000Z 21.1N 165.2W 85 KT 96HR VT 18/0000Z 22.5N 169.0W 70 KT 120HR VT 19/0000Z 24.0N 172.9W 60 KT $$ FORECASTER POWELL