WTPA42 PHFO 262030
TCDCP2

HURRICANE IOKE DISCUSSION NUMBER  28
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP012006
1100 AM HST SAT AUG 26 2006

HURRICANE IOKE MAINTAINS ITS CATEGORY 5 STATUS...WITH SUBJECTIVE 
DVORAK ESTIMATES FOR 26/1730Z OF 7.0 FROM CPHC AND JTWC...AND 6.5 
FROM KGWC. THIS SPANS A MAXIMUM SUSTAINED WIND SPEED RANGE OF 127 
TO 140 KT. THERE IS LITTLE CHANGE IN SATELLITE PRESENTATION FROM SIX 
HOURS AGO...WITH ADT FEEDBACK SHOWING AN EYE TEMP OF +10.8C. THE EYE 
REMAINS WELL-DEFINED...WITH SURROUNDING EYEWALL TEMPS RANGING FROM 
-71 TO -78C. THE COLDEST CLOUD TOPS ARE WITHIN THE SOUTHEAST 
SEMICIRCLE. WE WILL KEEP THE INITIAL INTENSITY AT 140 KT.

THE BOUNDARY VALUE PROBLEM WITH UKMET APPEARS TO BE 
FIXED...RESULTING IN A LEFTWARD SHIFT OF ALL CONSENSUS MODEL 
TRACKS AND A MUCH TIGHTER TRACK CLUSTER OVERALL. TRACK CLUSTER 
GUIDANCE CONTINUES THE TAKE IOKE ALONG A WEST SOUTHWESTERLY COURSE 
THROUGH 36 HOURS AS THIS SYSTEM RESPONDS TO WEAK RIDGING TO ITS
NORTHWEST. GFS SHOWS THIS RIDGE WILL SPLIT ALONG IOKE/S PATH BEYOND 
36 HOURS...DRAWING IOKE WESTWARD BY 48 HOURS THEN NORTHWESTWARD 
THROUGH 72...96 AND 120 HOURS. WHILE TAU THREE MOTION IS 245 DEGREES 
AT 8 KT...INITIAL MOTION IS CLOSER TO 215 DEGREES. TO ACCOUNT FOR 
THIS RATHER SHARP MOTION TOWARDS THE SOUTHWEST OVER THE PAST SIX 
HOURS...THE FORECAST TRACK HAS BEEN SHIFTED SLIGHTLY TO THE LEFT OF 
THE PREVIOUS ONE THROUGH 36 HOURS. THIS IS STILL WITHIN THE RANGE OF 
CONSENSUS AND UKMET GUIDANCE. WITH THE ADDITION OF CREDIBLE UKMET 
AND CONSENSUS GUIDANCE THIS ROUND...THE TIGHTER GUIDANCE CLUSTER HAS 
PROMPTED A SLIGHT TRACK SHIFT TO THE RIGHT BEYOND 36 HOURS. THE 
OVERALL EFFECT THROUGH 120 HOURS IS A SLIGHTLY SHARPER TURN TO THE 
RIGHT AS THE RIDGE COLLAPSES. THIS TRACK WILL BRING IOKE CLOSEST TO 
WAKE ISLAND AROUND 96 HOURS...BUT THE RIGHTWARD TRACK SHIFT 
INDICATES IOKE WILL PASS FARTHER TO THE NORTHEAST.

IOKE WILL LIKELY GO THROUGH AN EYEWALL REPLACEMENT CYCLE WITHIN THE 
NEXT 12 TO 24 HOURS...RESULTING IN SHORT TERM STRENGTH FLUCTUATIONS. 
HOWEVER...MODEL GUIDANCE KEEPS IOKE AT OR NEAR ITS CURRENT STRENGTH 
THROUGH 120 HOURS. AS AN OUTLIER...GFDL WANTS TO STRENGTHEN IOKE TO 
168 KT AT 96 HOURS. SINCE OUR PREVIOUS FORECAST MAXIMUM SUSTAINED 
WINDS AT 96 AN 120 HOURS WERE NEAR THE LOW END OF THE GUIDANCE 
RANGE...WE BUMPED THESE UP BY 5 KT AT EACH OF THESE TIMES THIS 
ROUND. INCREASING SST AND LOW SHEAR ALONG THE FORECAST TRACK 
WILL...AT THE VERY LEAST...GREATLY SLOW IOKE/S DECAY AT HIGHER 
LATITUDES. IF THIS PANS OUT...IOKE COULD ENTER THE RECORD BOOKS FOR 
LONGEVITY AS A CATEGORY 4 OR GREATER STORM.   

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      26/2100Z 18.2N 178.2W   140 KT
 12HR VT     27/0600Z 17.7N 179.5W   135 KT
 24HR VT     27/1800Z 17.3N 178.6E   140 KT
 36HR VT     28/0600Z 17.2N 176.6E   140 KT
 48HR VT     28/1800Z 17.2N 174.7E   140 KT
 72HR VT     29/1800Z 18.0N 171.2E   140 KT
 96HR VT     30/1800Z 20.0N 168.1E   140 KT
120HR VT     31/1800Z 22.9N 165.3E   135 KT
 
$$
FORECASTER POWELL