383 
 WTPA42 PHFO 142105
 TCDCP2
 
 HURRICANE FLOSSIE DISCUSSION NUMBER  25
 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP092007
 1100 AM HST TUE AUG 14 2007
 
 AT 1800 UTC...UW-CIMMS ESTIMATED HURRICANE FLOSSIE WAS UNDERGOING 
 ABOUT 25 KT OF SOUTHWEST SHEAR. GOOD OUTFLOW TO THE NORTH IS 
 COUNTERED BY HAMPERED OUTFLOW ELSEWHERE AS THIS SHEAR REALLY BEGINS 
 TO TAKE ITS TOLL. AIRCRAFT OBSERVATIONS SHOW FLOSSIE HAS AN OPEN 
 EYEWALL TO THE SOUTHEAST...WITH AN EXTRAPOLATED SURFACE WIND OF 90 
 KT AS OF 1600 UTC. AN 1800 UTC VORTEX MESSAGE LIMITS THIS SPEED TO 
 THE NORTHEAST EYEWALL...WITH WEAKER WINDS ELSEWHERE. CI VALUES OF 
 4.5 FROM CPHC AND SAB AS WELL AS 5.0 FROM JTWC...77 KT AND 90 
 KT...SHOW THIS SYSTEM HAS WEAKENED OVER THE PAST SIX HOURS. WE GIVE 
 FLOSSIE AN INITIAL STRENGTH OF 90 KT FOR THIS RUN. 
 
 TRACK GUIDANCE DIVERGES SHARPLY BEYOND 24 HOURS AS EACH MODEL 
 HANDLES THE DECLINE OF FLOSSIE DIFFERENTLY...BUT THE GUIDANCE MEAN 
 HAS CHANGED LITTLE. THE FORECAST TRACK CLOSELY FOLLOWS THE ARC OF 
 THE OLD TRACK...BUT AN INITIAL SLIGHT DEVIATION TO THE RIGHT WAS 
 NEEDED GIVEN RADAR-DERIVED INITIAL MOTION OF 299 DEGREES. THIS WILL 
 TAKE FLOSSIE A BIT CLOSER TO THE BIG ISLAND AT POINT OF CLOSEST 
 APPROACH...BUT CONTINUED WEAKENING WILL MITIGATE THE EFFECT THIS 
 CHANGE WILL HAVE ON THE BIG ISLAND. WE HAVE DECREASED THE TROPICAL 
 STORM WIND RADIUS TO 90 NM WITHIN THE NORTHWEST AND NORTHEAST 
 QUADRANTS BASED ON AIRCRAFT OBSERVATIONS AND SCATTEROMETER DATA. 
 THIS RADIUS IS STILL LARGE ENOUGH TO AFFECT THE BIG 
 ISLAND...PROMPTING CONTINUANCE OF THE TROPICAL STORM WARNING AND 
 HURRICANE WATCH FOR THAT ISLAND. WE DO NOT ANTICIPATE THE NEED FOR 
 WATCHES OR WARNINGS FOR THE SMALLER ISLANDS AT THIS TIME. RADAR 
 SHOWS FLOSSIE FORWARD SPEED HAS SLOWED TO 9 KT AND THIS IS REFLECTED 
 IN THE TRACK FORECAST AS WELL. HURRICANE FLOSSIE WILL PASS SOUTH OF 
 THE MAIN HAWAIIAN ISLANDS...WEAKENING BELOW HURRICANE STRENGTH 
 WITHIN 48 HOURS.  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INITIAL      14/2100Z 17.3N 154.9W    90 KT
  12HR VT     15/0600Z 18.0N 156.3W    80 KT
  24HR VT     15/1800Z 18.9N 158.2W    75 KT
  36HR VT     16/0600Z 19.8N 160.2W    65 KT
  48HR VT     16/1800Z 20.6N 162.4W    55 KT
  72HR VT     17/1800Z 22.0N 166.9W    40 KT
  96HR VT     18/1800Z 23.3N 171.2W    35 KT
 120HR VT     19/1800Z 24.4N 175.4W    25 KT
  
 $$
 FORECASTER POWELL