WTPA42 PHFO 202049
TCDCP2

TROPICAL STORM IOKE DISCUSSION NUMBER   4
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   CP012006
1100 AM HST SUN AUG 20 2006

IOKE CONTINUES TO STEADILY DEVELOP THIS MORNING. LOOKING PRETTY 
DECENT ON SATELLITE IMAGERY WITH A WELL DEVELOPED CDO AROUND THE 
CENTER. DVORAK FIXES ARE PRETTY MUCH A T3.0 FROM ALL THE 
AGENCIES...WHICH CORRELATES TO ROUGHLY 45KT STORM. UNFORTUNATELY 
THERE IS A PROBLEM WITH QUIKSCAT DATA TRANSMISSION BUT AN SSMI PASS 
AROUND 1718Z DID INDICATE SOME WINDS NEAR 40KTS ON THE EDGE OF THE 
CDO. THAT SAME SSMI PASS ALSO INDICATED CORE OF CONVECTION WRAPPING 
AROUND THE WEST AND SOUTH SIDES CLOSE TO THE CENTER. COULD BE A 
POSSIBLE EYE WALL DEVELOPMENT. GIVEN ALL THIS...HAVE UPPED INITIAL 
INTENSITY TO 45 KTS.

NO BIG CHANGES IN THE FORECAST PHILOSPHY. SHEAR ANALYSIS FROM CIMSS 
STILL SHOW IOKE SITTING IN A NICE AREA OF LESS THAN 5KT SHEAR. SSTS 
ARE ALSO AROUND 28C SO IT HAS PLENTY OF FUEL FOR IT TO CONTINUE TO 
DEVELOP. GIVEN THE BUMP UP IN INTENSITY HAVE ALSO ADJUSTED INTENSITY 
UPWARD A BIT THRU 36HRS SO NOW HAVE IOKE REACHING HURRICANE STRENGTH 
IN ABOUT 24HRS. GIVEN THE PRIME CONDITIONS THIS COULD HAPPEN 
EARLIER. 

EXPECT IOKE TO CONTINUE MOVING ROUGHLY WNW OR 280 DEGREES THE NEXT 
24 HOURS OR SO THEN BEING MAKING A SLOW TURN MORE NORTHWEST AS IT 
STARTS FEELING SOME INFLUENCE FROM THE UPPER TROF LOCATED NEAR AND 
JUST WEST OF THE DATELINE. DESPITE THE TURN...THE FORWARD MOTION IS 
EXPECTED TO SLOW SOME IN 3 TO 4 DAYS AS IOKE SHOULD BE GETTING CLOSE 
TO A COL AREA BETWEEN THAT DATELINE TROF AND ANOTHER UPPER LEVEL 
LOW EXPECTED TO FORM NORTH OF HAWAII. ALTHOUGH GUIDANCE IS IN FAIR 
AGREEMENT WITH THIS SCENARIO...THERE IS A LITTLE MORE SPREAD OUT AT 
DAYS 4 AND 5 SO CONFIDENCE IS A BIT LOWER. GUIDANCE HAS ALSO 
CONTINUED THE TREND OF A SLIGHT SHIFT WEST AT THE LONGER TIME RANGE 
SO HAVE FOLLOWED IN LINE AND STAYED FAIRLY CLOSE TO CONU THEN. 
FORECAST IS TO THE RIGHT OR EAST OF GFS AND UKMET BY DAY 4.  OUTSIDE 
OF THE MINOR INTENSITY ADJUSTMENTS MENTIONED ABOVE...STICKING FAIRLY 
CLOSE TO PREVIOUS PACKAGE. SHIPS STILL WANTING TO WEAKEN IOKE BELOW 
HURRICANE STRENGTH TOWARD THE END OF THE FORECAST PERIOD...BUT ON 
THE OTHER SIDE OF THE COIN...12Z GFDL KEEPS IOKE STRENGTHENING ALL 5 
DAYS REACHING 105KT AT 120 HOURS. 

THIS PACKAGE PRETTY MUCH MAINTAINS PREVIOUS APPROACH DISTANCE AND 
TIMING TO JOHNSTON ATOLL...WITH IOKE PASSING ABOUT 125NM SOUTHWEST 
OF JOHNSTON EARLY TUESDAY. THIS WOULD PUT IT WITHIN THE RADIUS OF 
TROPICAL STORM /35KT AND HIGHER/ WINDS. HIGHER SURF IS ALSO A 
POTENTIAL IMPACT AS IOKE PASSES BY. INTERESTS IN JOHNSTON ATOLL AND 
THE WILDLIFE REFUGE SHOULD MONITOR LATER FORECASTS FROM CPHC.  
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      20/2100Z 11.3N 162.6W    45 KT
 12HR VT     21/0600Z 12.1N 164.9W    55 KT
 24HR VT     21/1800Z 13.3N 167.8W    65 KT
 36HR VT     22/0600Z 14.5N 170.0W    70 KT
 48HR VT     22/1800Z 15.9N 172.0W    75 KT
 72HR VT     23/1800Z 18.4N 174.9W    75 KT
 96HR VT     24/1800Z 20.8N 177.1W    70 KT
120HR VT     25/1800Z 22.7N 178.2W    65 KT
 
$$
FORECASTER NASH