WTPA42 PHFO 231503 TCDCP2 HURRICANE IOKE DISCUSSION NUMBER 15 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP012006 500 AM HST WED AUG 23 2006 ALTHOUGH THERE HAS BEEN AN INTERMITTENT RAGGED EYE FEATURE APPARENT IN THE INFRARED IMAGERY OVER THE PAST FEW HOURS...FOR THE MOST PART THE EYE REMAINS CLOUD-FILLED. SUBJECTIVE DVORAK INTENSITY ESTIMATES HAVE REMAINED CONSTANT FROM ALL THE AGENCIES OVER THE PAST 12 HOURS...AND WE WILL MAINTAIN A CURRENT INTENSITY OF 90 KT. THE INITIAL MOTION IS 320/6. THERE IS LITTLE CHANGE TO THE FORECAST PHILOSOPHY. MODEL GUIDANCE REMAINS TIGHTLY CLUSTERED...ESPECIALLY IN THE NEAR TERM. THROUGH THE NEXT 36 TO 48 HOURS...IOKE WILL CONTINUE TO BE DRAWN SLOWLY NORTHWESTWARD ALONG THE PERIPHERY OF THE SUBTROPICAL RIDGE AND TOWARD A NEARLY STATIONARY EXTRATROPICAL LOW JUST WEST OF THE DATELINE NEAR 28N. AFTERWARD...THE EXTRATROPICAL LOW IS EXPECTED TO LIFT BACK INTO THE NORTH PACIFIC WESTERLIES...AND STRONG DEEP LAYER RIDGING BUILDS TO THE NORTH AND WEST OF IOKE WHICH WILL FORCE THE CYCLONE BACK TOWARD THE WEST- SOUTHWEST. THE MODEST WESTERLY SHEAR APPEARS TO BE RELAXING AS SATELLITE IMAGERY INDICATES IMPROVING OUTFLOW OVER IOKE. MODELS AGREE THAT THE SHEAR WILL CONTINUE TO RELAX THROUGH 36 HOURS AS IOKE MOVES UNDERNEATH AN UPPER LEVEL RIDGE AXIS. THE SSTS ARE WARM AND SO CONDITIONS APPEAR TO BE FAVORABLE FOR MODEST STRENGTHENING. IN THE LONGER TERM...THE UPPER RIDGE AXIS WILL SHIFT MORE QUICKLY WESTWARD AND IOKE WILL LIKELY BEGIN TO FEEL THE INFLUENCE OF A RATHER STRONG DIGGING TROUGH BETWEEN ABOUT 160W AND 170W...WITH INCREASING NORTHERLY SHEAR INDUCING WEAKENING. FORECAST POSITIONS AND MAX WINDS INITIAL 23/1500Z 17.6N 170.7W 90 KT 12HR VT 24/0000Z 18.3N 171.5W 90 KT 24HR VT 24/1200Z 19.0N 172.7W 95 KT 36HR VT 25/0000Z 19.7N 173.9W 95 KT 48HR VT 25/1200Z 20.3N 175.0W 90 KT 72HR VT 26/1200Z 20.5N 177.6W 85 KT 96HR VT 27/1200Z 19.5N 179.8W 75 KT 120HR VT 28/1200Z 18.5N 178.3E 65 KT $$ FORECASTER R BALLARD/HOUSTON