791 
 WTPA42 PHFO 230237
 TCDCP2
 
 HURRICANE NEKI DISCUSSION NUMBER  18
 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP032009
 500 PM HST THU OCT 22 2009
 
 HURRICANE NEKI IS SLOWLY WEAKENING AS STRONG SOUTHWESTERLY SHEAR
 CONTINUES TO IMPACT THE SYSTEM. FIXES FROM CPHC...JTWC...AND SAB
 ALL CAME IN WITH CI VALUES OF 4.5 TO 5.0. RECENT IR SATELLITE 
 IMAGERY SHOWS WARMING CLOUD TOPS SO THE INITIAL INTENSITY HAS BEEN 
 LOWERED TO 85 KT.
 
 MODELS ARE IN GOOD AGREEMENT WITH A CONTINUED NORTH-NORTHEAST MOTION 
 IN THE SHORT TERM THEN A TURN MORE TO THE NORTHEAST WITH GRADUAL
 ACCELERATION EXPECTED AS THE SYSTEM INTERACTS WITH AN ENCROACHING
 FRONT AND ITS ASSOCIATED UPPER LEVEL TROUGH. THE LATEST FORECAST
 TRACK IS PRETTY MUCH DOWN THE MIDDLE OF THE GUIDANCE AND ESSENTIALLY 
 UNCHANGED FROM THE PREVIOUS FORECAST.
 
 NEKI WILL REMAIN OVER 26 C OR WARMER WATER THROUGH ABOUT 36 
 HOURS...THEN MOVE ACROSS COOLER WATERS THROUGH THE REST OF ITS 
 FORECAST TRACK. THE LATEST UW-CIMSS VERTICAL WIND SHEAR PRODUCT 
 SHOWS SOUTHWEST SHEAR OF 26 KT. THIS STRONG SHEAR IS EXPECTED TO 
 CONTINUE FOR THE NEXT SEVERAL DAYS AND WILL BE THE PRIMARY KEY IN 
 THE WEAKENING PROCESS. MODELS ARE IN SOME DISAGREEMENT ON THE 
 SPEED OF THIS WEAKENING PROCESS WITH SHIPS SHOWING A REMNANT LOW IN 
 72 HOURS WHILE HWFI STILL SHOWING A STRONG TROPICAL STORM THROUGH 
 96 HOURS. THE GFDI KEEPS NEKI A HURRICANE THROUGH 84 HOURS WHICH 
 SEEMS UNREASONABLE DUE TO THE INCREASING SHEAR. NEKI IS FORECAST TO 
 WEAKEN TO A TROPICAL STORM BY 48 HOURS...THEN TO A DEPRESSION BY 120 
 HOURS WHEN THE SYSTEM WILL LIKELY BE CLASSIFIED AS EXTRATROPICAL.
 
 ON ITS CURRENT TRACK...NEKI IS LIKELY BEGINNING TO IMPACT THE 
 PAPAHANAUMOKUAKEA NATIONAL MONUMENT NEAR FRENCH FRIGATE SHOALS. 
 CONDITIONS IN THE PARTS OF THE WARNING AREA WILL CONTINUE TO 
 DETERIORATE TONIGHT AND EARLY FRIDAY...AND A HURRICANE WARNING 
 REMAINS IN EFFECT FOR THE MONUMENT FROM NIHOA ISLAND TO MARO REEF. 
 LARGE SWELLS FROM THE SOUTH WILL CONTINUE TO BUILD LATE TODAY AND 
 TONIGHT ACROSS THE WARNING AREA WITH SEAS GREATER THAN 20 FT AND 
 SURF UP 25 FT EXPECTED.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      23/0300Z 22.1N 166.0W    85 KT
  12HR VT     23/1200Z 23.7N 165.6W    80 KT
  24HR VT     24/0000Z 25.7N 164.7W    75 KT
  36HR VT     24/1200Z 27.8N 163.4W    65 KT
  48HR VT     25/0000Z 29.9N 161.9W    60 KT
  72HR VT     26/0000Z 33.9N 158.8W    45 KT
  96HR VT     27/0000Z 37.9N 155.4W    35 KT
 120HR VT     28/0000Z 42.3N 151.7W    30 KT...EXTRATROPICAL
  
 $$
 FORECASTER BURKE