WTPA45 PHFO 220250

TCDCP5



HURRICANE OLAF DISCUSSION NUMBER  29

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP192015

500 PM HST WED OCT 21 2015



THE SATELLITE CLOUD PATTERN AROUND OLAF HAS WEAKENED SINCE THIS

MORNING. THE SURROUNDING TOPS HAVE WARMED AND THE EYE HAS COOLED...

BUT SOME OF THESE CHANGES HAVE OCCURRED SINCE THE 21/2330 UTC DVORAK

SUBJECTIVE ESTIMATES WERE DONE. THE ESTIMATES FROM HFO...JTWC AND

SAB WERE ALL UNCHANGED SINCE THIS MORNINGS WITH CURRENT INTENSITIES

OF 5.5/102 KT. THE UW-CIMSS OBJECTIVE ESTIMATE WAS 5.7/107.2 KT. I

HAVE KEPT THE INITIAL INTENSITY AT 105 KT.



THE INITIAL MOTION FOR THIS ADVISORY IS 315/08 KT WITH GOOD

CONFIDENCE IN RECENT CENTER POSITIONS. THERE IS NO CHANGE IN THE

REASONING FOR THE TRACK FORECAST SINCE THE PREVIOUS ADVISORY. OLAF

IS EXPECTED TO CONTINUE MOVING TOWARD A WEAKNESS IN THE SUBTROPICAL

RIDGE...TOWARD THE NORTHWEST OVER THE NEXT 24 HOURS...GRADUALLY

TURNING TOWARD THE NORTH IN 72 HOURS. A STRONG SHORT-WAVE TROUGH IS

FORECAST TO DROP SOUTH TOWARD THE WEAKNESS IN THE SUBTROPICAL RIDGE

STARTING ON SUNDAY.  AS THIS OCCURS...OLAF WILL MOVE NORTH OF THE

RIDGE AXIS AND ACCELERATE TOWARD THE NORTHEAST. THE CURRENT FORECAST

CLOSELY FOLLOWS OUR PREVIOUS FORECASTS AND REMAINS CLOSE TO THE

CONSENSUS OF THE TRUSTED MODELS.



THE SEA SURFACE TEMPERATURE...SST...ALONG THE FORECAST TRACK IS

EXPECTED TO GRADUALLY COOL FROM NEAR 29 DEGREES CELSIUS THIS AFTERNOON

TO 26 DEGREES 120 HOURS FROM NOW. THE INITIAL VERTICAL WIND SHEAR...

VWS...WAS RATHER LOW WITH SHIPS SHOWING 3 KT FROM THE SOUTHEAST

UW-CIMSS SHOWING 15 KT FROM THE SOUTHWEST. SHIPS SHOWS THE VWS

INCREASING STEADILY TO 28 KT SUNDAY NIGHT. SHIPS SHOWS SLIGHT

INTENSIFICATION OVER THE NEXT 24 HOURS...THEN STEADY WEAKENING. ICON

AND IVCN SHOW GRADUAL WEAKENING FROM THE START. I HAVE FOLLOWED THE

CONSENSUS MODELS WITH SLOW WEAKENING OVER THE NEXT 24 HOURS...THEN

FASTER WEAKENING DUE TO STRONGER VWS AND LOWER SST.





FORECAST POSITIONS AND MAX WINDS



INIT  22/0300Z 12.6N 145.6W  105 KT 120 MPH

 12H  22/1200Z 13.3N 146.2W  100 KT 115 MPH

 24H  23/0000Z 14.6N 146.9W  100 KT 115 MPH

 36H  23/1200Z 15.9N 147.1W   95 KT 110 MPH

 48H  24/0000Z 17.5N 147.0W   90 KT 105 MPH

 72H  25/0000Z 20.0N 146.2W   70 KT  80 MPH

 96H  26/0000Z 22.0N 144.5W   65 KT  75 MPH

120H  27/0000Z 25.5N 141.0W   50 KT  60 MPH



$$

FORECASTER DONALDSON