WTPA42 PHFO 220316 CCA TCDCP2 HURRICANE NEKI DISCUSSION NUMBER 14 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI CP032009 500 PM HST WED OCT 21 2009 AFTER RAPID INTENSIFICATION EARLIER TODAY...THE RATE OF INTENSIFICATION OF NEKI HAS SLOWED. FIXES FROM PHFO AND JTWC CAME IN AT 5.5...SAB REPORTED 6.0...AND CIMSS ADT CALCULATED 6.2. THE INITIAL INTENSITY IS INCREASED TO 105 KT...AN AVERAGE OF THE FIX AGENCIES. UPPER LEVEL OUTFLOW REMAINS GOOD IN MOST QUADRANTS DUE TO AN UPPER LEVEL ANTICYCLONE PARKED JUST SOUTH OF THE MAIN HAWAIIAN ISLANDS. HOWEVER...OUTFLOW ALONG THE WESTERN QUADRANT APPEARS TO BE PARTIALLY RESTRICTED DUE TO AN UPPER LEVEL TROUGH MOVING DOWN FROM THE NORTH. THIS IS PRODUCING INCREASING WEST-SOUTHWESTERLY WIND SHEAR OF 16 KT ACCORDING TO THE 0000 UTC CIMSS VERTICAL WIND SHEAR ESTIMATE. THIS SHEAR DOES NOT APPEAR TO BE AFFECTING THE CORE YET...AND SINCE NEKI SITS OVER 28 CELSIUS WATER...SOME ADDITIONAL STRENGTHENING IS POSSIBLE TONIGHT. THE INITIAL MOTION IS NOW TO THE DUE NORTH AT 8 KT TOWARD A WEAKNESS IN THE SUBTROPICAL RIDGE TO THE NORTH. THE RIDGE IS BEING ERODED BY A FRONT MOVING OVER LISIANSKI AND ITS ASSOCIATED BROAD UPPER LEVEL TROUGH THAT HAS HAS EDGED SOUTHWARD TO 25N. NEKI IS EXPECTED TO CONTINUE MOVING TO THE NORTH TOWARD THE WEAKNESS IN THE RIDGE THEN GRADUALLY SHIFT TO THE NORTHEAST FRIDAY NIGHT AS IT INTERACTS WITH THE UPPER LEVEL TROUGH. THE TRACK HAS AGAIN BEEN NUDGED TO THE RIGHT AND NOW LIES ALONG THE RIGHT SIDE OF THE GUIDANCE ENVELOPE TO BE CLOSE TO THE WELL-PERFORMING HWRF AND GFDL MODELS THROUGH THE WEEKEND. AS NEKI CONTINUES MOVING NORTHWARD TOWARD THE NEARLY STATIONARY UPPER LEVEL TROUGH...IT WILL ENCOUNTER GREATER VERTICAL WIND SHEAR THAT WILL INDUCE WEAKENING. THE RATE OF WEAKENING IS IN THE MIDDLE OF THE GUIDANCE ENVELOPE. THIS BRINGS NEKI TO A TROPICAL STORM BY DAY FIVE...BUT THE FATE OF NEKI WILL HINGE UPON ITS INTERACTION WITH A FRONT APPROACHING FROM THE NORTHWEST. BY DAY FIVE...THESE MODELS SUGGEST THAT NEKI MAY BE RACING OFF TO THE NORTHEAST AS IT INTERACTS WITH THE APPROACHING FRONT. ON THE CURRENT TRACK...NEKI WILL BE APPROACHING THE PAPAHANAUMOKUAKEA NATIONAL MONUMENT NEAR FRENCH FRIGATE SHOALS ON FRIDAY...AND A HURRICANE WARNING REMAINS FOR THE MONUMENT FROM NIHOA ISLAND TO MARO REEF. THE HURRICANE WATCH FROM MARO REEF TO LISIANSKI WITHIN THE MONUMENT HAS BEEN CHANGED TO A TROPICAL STORM WATCH AS THE TRACK HAS SHIFTED EASTWARD. LARGE SWELLS FROM THE SOUTH WILL BUILD TONIGHT AND CONDITIONS WILL DETERIORATE ACROSS PORTIONS OF THE WARNING AREA THURSDAY...WITH SEAS GREATER THAN 20 FT AND SURF UP 25 FT EXPECTED. FORECAST POSITIONS AND MAX WINDS INITIAL 22/0300Z 18.7N 166.7W 105 KT 12HR VT 22/1200Z 19.9N 166.6W 110 KT 24HR VT 23/0000Z 21.4N 166.5W 105 KT 36HR VT 23/1200Z 23.1N 166.3W 90 KT 48HR VT 24/0000Z 24.8N 165.5W 80 KT 72HR VT 25/0000Z 27.4N 163.5W 70 KT 96HR VT 26/0000Z 29.9N 161.2W 65 KT 120HR VT 27/0000Z 34.0N 158.9W 55 KT $$ FORECASTER WROE