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 540 
 WTPA45 PHFO 231444
 TCDCP5
 
 HURRICANE OLAF DISCUSSION NUMBER  35
 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP192015
 500 AM HST FRI OCT 23 2015
  
 A RAGGED 10 NM WIDE EYE EMBEDDED WITHIN AN ASYMMETRIC DEEP
 CONVECTIVE RING DESCRIBES THE CENTRAL FEATURE FOR OLAF. SOME
 ADDITIONAL BANDING WITHIN THE NORTH AND EAST QUADRANTS GIVES US THE
 IMPRESSION THAT OLAF ORGANIZATION HAS IMPROVED SLIGHTLY SINCE LAST
 EVENING. SUBJECTIVE DVORAK SATELLITE INTENSITY ESTIMATES ARE
 UNCHANGED FROM EARLIER...5.5...102 KT...FROM ALL THREE SATELLITE
 CENTERS. HOWEVER...UW-CIMSS ADT INCREASED DRAMATICALLY TO AN
 UNREPRESENTATIVE 6.7...132 KT. GIVEN THE SLIGHTLY BETTER OVERALL
 SATELLITE PRESENTATION...AND AS A NOD TO THE ADT TREND...WE WILL
 ASSIGN 105 KT AS THE INITIAL INTENSITY FOR THIS ADVISORY.
 
 INITIAL MOTION IS JUST EAST OF DUE NORTH...OR 005/08 KT...AS OLAF
 CONTINUES MOVING INTO A WEAKNESS IN THE SUBTROPICAL RIDGE FAR
 NORTHEAST OF THE MAIN HAWAIIAN ISLANDS. A LARGE NORTHWARD COMPONENT
 WILL CONTINUE THROUGH THE FORECAST PERIOD...WITH A PAIR OF TROUGHS
 PASSING EASTWARD TO THE NORTH OF OLAF NUDGING THIS SYSTEM EVER MORE
 INSISTENTLY TO THE EAST THROUGH DAY FOUR. TRACK GUIDANCE HAS CHANGE
 VERY LITTLE THROUGH 96 HOURS. HOWEVER...GFS JOINED ECMWF IN
 DEPICTING A SUDDEN SWING TO THE NORTHWEST BETWEEN 96 AND 120
 HOURS...DRAGGING CONSENSUS LEFTWARD LATE IN THE FORECAST PERIOD AS 
 WELL. THIS MAY BE DUE TO BOTH GLOBAL MODELS SEEING A DECAPITATED 
 OLAF SUDDENLY COMING UNDER THE INFLUENCE OF SHALLOW LOW LEVEL FLOW 
 ALONG THE SOUTH FLANK OF THE SUBTROPICAL RIDGE AT THAT POINT. 
 HOWEVER...BOTH GFS AND ECMWF KEEP OLAF RATHER STRONG ON DAYS FOUR 
 AND FIVE...SO PERHAPS RIDGE STRENGTHENING TO THE NORTH OF OLAF IS 
 SEEN. EITHER WAY...THE DAY FIVE FORECAST POINT WAS ADJUSTED TO THE 
 LEFT TO ACCOUNT FOR THIS EFFECT...LEAVING THE REMAINING FORECAST 
 POINTS PRETTY MUCH INTACT FROM LAST TIME.
 
 SHIPS AND UW-CIMSS CONTINUE TO DISAGREE ON THE AMOUNT OF SHEAR
 ACROSS OLAF...RANGING FROM 15 TO 25 KT...RESPECTIVELY. WE ASSUME
 THAT THE AMOUNT OF SHEAR PRESENT IS CLOSER TO THE LOWER VALUE SINCE
 THE INNER CORE OF OLAF APPEARS TO BE UNAFFECTED. INTENSITY GUIDANCE
 SHOWS WEAKENING ACROSS THE BOARD THROUGH THE NEXT FIVE DAYS AS SHEAR
 INCREASES AND SSTS DROP...WITH SHIPS DISSIPATING OLAF BY DAY FOUR.
 THE GLOBAL MODELS WEAKEN OLAF MUCH MORE SLOWLY...WITH GFS DEPICTING
 OLAF STILL AT TROPICAL STORM STRENGTH ON DAY FIVE. WE WILL KEEP THE
 SAME STEADY WEAKENING TREND FROM LAST TIME...EXCEPT FOR A BUMP UP TO
 95 KT AT 24 HOURS TO ACCOUNT FOR THE INITIAL INTENSITY INCREASE. WE
 FORECAST OLAF WILL REMAIN A MINIMAL HURRICANE AT 72 HOURS...THEN
 WEAKEN TO A TROPICAL STORM AT 96 AND 120 HOURS.
 
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  23/1500Z 15.9N 146.2W  105 KT 120 MPH
  12H  24/0000Z 16.9N 145.9W  100 KT 115 MPH
  24H  24/1200Z 18.3N 145.5W   95 KT 110 MPH
  36H  25/0000Z 19.5N 144.9W   90 KT 105 MPH
  48H  25/1200Z 20.7N 144.1W   85 KT 100 MPH
  72H  26/1200Z 23.3N 141.8W   65 KT  75 MPH
  96H  27/1200Z 25.8N 137.9W   60 KT  70 MPH
 120H  28/1200Z 30.3N 138.0W   45 KT  50 MPH
  
 $$
 FORECASTER POWELL
 
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