609 
 WTPA45 PHFO 250859
 TCDCP5
 
 HURRICANE OLAF DISCUSSION NUMBER  42
 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP192015
 1100 PM HST SAT OCT 24 2015
  
 OLAF REMAINS RATHER WELL-ORGANIZED THIS EVENING...WITH INFRARED
 SATELLITE IMAGERY REVEALING A RAGGED BUT CLOUD-FREE EYE DURING THE
 PAST FEW HOURS. 0327Z WINDSAT AND 0423Z SSMS MICROWAVE PASSES ALSO
 DEPICTED A WELL-DEFINED EYE. HOWEVER...DEEP CONVECTION AROUND THE
 EYE HAS WEAKENED INTERMITTENTLY DURING THE EVENING...AND THE EYE HAS
 BEEN OPEN TO THE SOUTH AT TIMES. SUBJECTIVE DVORAK CURRENT INTENSITY 
 ESTIMATES CAME IN AT 4.5/77 KT FROM ALL THREE AGENCIES...WHILE THE 
 UW-CIMSS ADT CURRENT INTENSITY ESTIMATE REMAINS SIGNIFICANTLY 
 STRONGER AT 5.3/97 KT. THE INITIAL INTENSITY FOR THIS ADVISORY HAS 
 BEEN LOWERED TO 80 KT.
 
 OLAF APPEARS TO HAVE SLOWED DOWN AND TURNED SLIGHTLY TO THE RIGHT
 DURING THE EVENING...AND HAVE USED A LONGER-TERM 12 HOUR MOTION OF
 035/07 KT FOR THIS ADVISORY. THE CYCLONE LIES BETWEEN A NORTHEAST
 TO SOUTHWEST ORIENTED DEEP-LAYER RIDGE TO THE SOUTHEAST...AND AN
 EAST TO WEST ORIENTED RIDGE CENTERED WELL TO THE WEST...NEAR
 THE INTERNATIONAL DATE LINE. WATER VAPOR IMAGERY SHOWS A POTENT
 MID-LATITUDE TROUGH MOVING QUICKLY EASTWARD TO THE NORTH OF
 HAWAII...AND THIS TROUGH IS EXPECTED TO EXERT AN INCREASING
 INFLUENCE ON OLAF THROUGH AT LEAST THE NEXT 48 HOURS...WITH THE 
 CYCLONE MOVING MORE QUICKLY TOWARD THE NORTHEAST. GUIDANCE DIVERGES
 SIGNIFICANTLY AT 72 HOURS AND BEYOND...WITH THE GFS AND GFDL 
 CONTINUING TO ACCELERATE OLAF OFF TO THE NORTHEAST AS IT BECOMES 
 FULLY ENTRAINED IN THE MID-LATITUDE TROUGH...WHILE MOST OF THE OTHER 
 MODELS INCLUDING THE ECMWF TURN THE WEAKENING CYCLONE BACK TOWARD 
 THE SOUTHWEST...TO THE SOUTH OF A BUILDING DEEP-LAYER RIDGE OVER THE 
 NORTHEAST PACIFIC. THE GUIDANCE ENVELOPE DID SHIFT SIGNIFICANTLY 
 EASTWARD WITH THIS CYCLE. THE NEW OFFICIAL FORECAST REPRESENTS A 
 BLEND BETWEEN THE PREVIOUS TRACK AND THE TVCN MODEL CONSENSUS 
 THROUGH 48 HOURS...THEN IS MOST SIMILAR TO THE ECMWF AT 72 HOURS AND 
 BEYOND.
 
 SATELLITE IMAGERY INDICATES THAT WEST/SOUTHWEST VERTICAL WIND SHEAR
 CONTINUES TO IMPACT OLAF...WITH OUTFLOW RESTRICTED IN THOSE 
 QUADRANTS. UW-CIMSS AND SHIPS SHEAR MAGNITUDE ESTIMATES RANGE FROM 
 21 TO 27 KT...AND THE SHEAR SHOULD REMAIN ROUGHLY THE SAME OR 
 INCREASE SOMEWHAT DURING THE NEXT 48 HOURS AS THE MID-LATITUDE 
 TROUGH MOVES CLOSER TO THE CYCLONE. OLAF WILL ALSO BE MOVING OVER 
 COOLER SEA SURFACE TEMPERATURES AND DECREASING OCEAN HEAT CONTENT 
 VALUES DURING THE NEXT FEW DAYS. STEADY WEAKENING IS FORECAST. THE 
 OFFICIAL INTENSITY FORECAST IS CLOSE TO THE IVCN CONSENSUS...AND 
 REPRESENTS A COMPROMISE BETWEEN THE FASTER WEAKENING RATES DEPICTED 
 BY THE SHIPS AND LGEM...AND THE SLOWER RATES SHOWN BY MOST OF THE 
 DYNAMICAL MODELS. WE CONTINUE TO SHOW OLAF AS A POST-TROPICAL 
 REMNANT LOW AT DAYS 4 AND 5. 
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  25/0900Z 21.2N 143.8W   80 KT  90 MPH
  12H  25/1800Z 22.1N 143.2W   70 KT  80 MPH
  24H  26/0600Z 23.6N 141.9W   60 KT  70 MPH
  36H  26/1800Z 25.0N 140.0W   50 KT  60 MPH
  48H  27/0600Z 26.7N 137.5W   40 KT  45 MPH
  72H  28/0600Z 28.0N 134.0W   30 KT  35 MPH
  96H  29/0600Z 26.5N 133.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
 120H  30/0600Z 24.5N 140.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
  
 $$
 FORECASTER JACOBSON