WTPA45 PHFO 232100

TCDCP5



HURRICANE OLAF DISCUSSION NUMBER  36

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP192015

1100 AM HST FRI OCT 23 2015



THE SATELLITE PRESENTATION OF OLAF HAS CHANGED LITTLE SINCE THE

PREVIOUS ADVISORY...WITH THE CLOUD-FILLED EYE SURROUNDED BY A

BROKEN RING OF DEEP CONVECTION. RECENT MICROWAVE IMAGERY SHOWS THAT

THE STRUCTURE OF OLAF HAS IMPROVED SOMEWHAT SINCE THIS

TIME YESTERDAY...BUT ALSO HIGHLIGHTS THE BREAKS IN THE EYE WALL

THAT HAVE RECENTLY BEEN ROTATING AROUND THE CENTER. LATEST

SUBJECTIVE DVORAK INTENSITY ESTIMATES FROM PHFO/SAB/PGTW WERE

5.5/102 KT ACROSS THE BOARD...AND THE INITIAL INTENSITY ESTIMATE

FOR THIS ADVISORY HAS BEEN MAINTAINED AT 105 KT.



OLAF IS TRACKING DUE NORTH THIS MORNING...WITH AN INITIAL MOTION OF

360/09 KT. THE SYNOPTIC SETUP FEATURES A MID-LEVEL HIGH CENTERED

EAST OF OLAF...WITH ANOTHER MID-LEVEL HIGH CENTERED JUST WEST OF THE

DATE LINE. THE RIDGE ASSOCIATED WITH DATE LINE HIGH EXTENDS EASTWARD

OVER THE HAWAIIAN ISLANDS...WITH THE EASTERN TERMINUS OF THIS RIDGE

LOCATED JUST NORTHWEST OF OLAF. WATER VAPOR IMAGERY SHOWS A WELL-

DEFINED TROUGH ALOFT DIGGING SOUTHEASTWARD SEVERAL HUNDRED MILES

NORTHWEST OF OLAF. THUS A SOUTHERLY STEERING FLOW PREVAILS OVER

OLAF...PRIMARILY PROVIDED BY THE HIGH TO THE EAST...BUT ALSO

PROVIDED BY SHORTWAVE TROUGHS RIDING AROUND THE MID-LEVEL HIGH TO

THE DISTANT WEST. OVER TIME...THE HIGH TO THE EAST IS EXPECTED TO

SLIDE INTO A POSITION SOUTH OLAF...WHILE SHORTWAVE TROUGHS PASS FROM

WEST TO EAST WELL TO THE NORTH OF OLAF. THIS WILL INDUCE A MOTION

TOWARD THE NORTH-NORTHEAST...AND THEN TOWARD THE NORTHEAST. AT THE

VERY END OF THE FORECAST PERIOD..THE RIDGE CENTERED WEST OF THE DATE

LINE WILL SHIFT EASTWARD...EVENTUALLY BUILDING TO THE NORTH OF OLAF.

GLOBAL MODELS RESPOND BY SLOWING OLAF/S FORWARD MOTION...AND THE

UPDATED OFFICIAL FORECAST FOLLOWS SUIT. THE UPDATED FORECAST TRACK

LIES CLOSE TO THE TVCN AND GFEX...AND IS SLIGHTLY TO THE RIGHT OF

THE PREVIOUS THROUGH 36 HOURS...AND THEN LIES ALONG THE PREVIOUS BY

48 HOURS...BUT INDICATES A SLOWER FORWARD SPEED. THE 96 AND 120 HOUR

UPDATED TRACK FORECAST REPRESENTS A SLOWER FORWARD MOTION THAN

PREVIOUSLY INDICATED.



THE FORECAST TRACK TAKES OLAF OVER STEADILY DECREASING SSTS...WITH

VALUES EXPECTED TO DIMINISH FROM 28C CURRENTLY...TO NEAR 23C BY DAY

5. VERTICAL SHEAR IS FORECAST TO INCREASE OVER THE NEXT 24 HOURS...

PRIMARILY FROM THE SOUTHWEST...AND THEN REMAIN RELATIVELY STRONG /20

TO 30 KT/ THROUGH THE REMAINDER OF THE FORECAST PERIOD. THIS IS

EXPECTED TO LEAD TO STEADY WEAKENING THROUGH THE FORECAST PERIOD.

THE UPDATED INTENSITY FORECAST REPRESENTS A BLEND OF THE PREVIOUS

AND THE INTENSITY CONSENSUS IVCN...BUT REMAINS HIGHER THAN MOST OF

THE INTENSITY GUIDANCE...INCLUDING SHIPS...WHICH INDICATES

DISSIPATION AFTER 72 HOURS. IF GUIDANCE CONTINUES ON CURRENT

TRENDS...THEN THE NEXT FORECAST WILL LIKELY INDICATE A GREATER RATE

OF WEAKENING...ESPECIALLY LATE IN THE FORECAST.





FORECAST POSITIONS AND MAX WINDS



INIT  23/2100Z 17.1N 146.3W  105 KT 120 MPH

 12H  24/0600Z 18.2N 145.9W   95 KT 110 MPH

 24H  24/1800Z 19.4N 145.3W   85 KT 100 MPH

 36H  25/0600Z 20.4N 144.8W   80 KT  90 MPH

 48H  25/1800Z 21.6N 144.1W   70 KT  80 MPH

 72H  26/1800Z 23.7N 142.4W   55 KT  65 MPH

 96H  27/1800Z 25.6N 140.0W   45 KT  50 MPH

120H  28/1800Z 26.6N 139.0W   35 KT  40 MPH



$$

FORECASTER BIRCHARD