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