WTPA45 PHFO 221500

TCDCP5



HURRICANE OLAF DISCUSSION NUMBER  31

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP192015

500 AM HST THU OCT 22 2015



THE EYE OF OLAF WAS SURROUNDED BY AN IMPRESSIVE RING OF COLD

CUMULONIMBUS CLOUD TOPS IN INFRARED SATELLITE IMAGERY EARLY THIS

MORNING. THE OUTFLOW PATTERN ALSO REMAINS ROBUST THIS MORNING.

THE LATEST SUBJECTIVE DVORAK INTENSITY ESTIMATES FROM JTWC AND SAB

WERE 5.0/90 KT...WHILE PHFO WAS 5.5/102 KT. THE MOST RECENT UW-CIMSS

ADT ESTIMATE WAS ALSO 5.0/90 KT. DUE TO THE APPARENT WEAKENING OF

OLAF TONIGHT...WE HAVE LOWERED THE INITIAL INTENSITY TO 100 KT. NOTE

THAT A 0646Z ASCAT PASS WAS USED TO ADJUST THE INITIAL WIND RADII

FOR THIS ADVISORY.



THE INITIAL MOTION FOR THIS ADVISORY IS 320/06 KT. OLAF IS EXPECTED

TO CONTINUE MOVING SLOWLY NORTHWESTWARD...WITH A GRADUAL TURN

TOWARD THE NORTH-NORTHWEST INTO A WEAKNESS IN THE SUBTROPICAL

RIDGE DURING THE NEXT 24 HOURS. IT IS THEN EXPECTED TO MOVE TOWARD

THE NORTH DURING THE 24 TO 48 HOUR TIME PERIOD. THIS WILL BE

FOLLOWED BY A TURN TOWARD THE NORTH-NORTHEAST AND THEN THE NORTHEAST

DURING DAYS 3 AND 4 DUE TO A DEEP TROUGH DIGGING SOUTH TOWARD

THE SYSTEM LATER THIS WEEKEND. ONCE THIS OCCURS...OLAF IS FORECAST

TO ACCELERATE NORTHEASTWARD BY DAY 5. THE CURRENT FORECAST HAS BEEN

SHIFTED SLIGHTLY TO THE RIGHT OF THE PREVIOUS ONE. THIS FORECAST

TRACK IS CLOSE TO THE MOST RECENT TVCN AND GFEX CONSENSUS GUIDANCE...

AS WELL AS THE HWRF MODEL.



THE LATEST ESTIMATES OF ENVIRONMENTAL VERTICAL WIND SHEAR IN THE

VICINITY OF OLAF ARE 5 KT FROM THE SOUTH-SOUTHWEST ACCORDING TO

SHIPS...AND 17 KT FROM THE SOUTHWEST ACCORDING TO UW-CIMSS. THE

CIRA ANALYSIS OF OCEAN HEAT CONTENT /OHC/ ALONG THE FORECAST

TRACK OF OLAF CONTINUES TO SHOW IT WILL MOVE OVER MODEST VALUES OF

THIS PARAMETER DURING THE NEXT 2 TO 3 DAYS. HOWEVER...THE OHC

REMAINS SLIGHTLY LOWER COMPARED WITH THE OCEANIC AREAS TO THE EAST

AND WEST OF THE FORECAST TRACK. THIS IS LIKELY DUE TO THE LARGE

NUMBER OF TROPICAL CYCLONES THAT HAVE TRAVERSED THESE WATERS DURING

THE PAST COUPLE OF MONTHS CAUSING A LINGERING UPWELLING SIGNAL. THE

SEA SURFACE TEMPERATURES...SST...ALONG THE FORECAST TRACK ARE

EXPECTED TO GRADUALLY COOL FROM SLIGHTLY ABOVE 28C NOW TO AROUND 25C

5 DAYS FROM NOW. THE LATEST SHIPS GUIDANCE SHOWS A STEADY INCREASE

IN THE VERTICAL WIND SHEAR FROM THE SOUTHWEST DURING THE NEXT 24

HOURS. THIS IS FOLLOWED BY INCREASINGLY HOSTILE SOUTHWESTERLY SHEAR

VALUES BEYOND DAY 1...WITH VALUES OF AROUND 30 KT EXPECTED BY DAY

4. SHIPS SHOWS LITTLE CHANGE IN INTENSITY DURING THE NEXT 12

HOURS...FOLLOWED BY STEADY WEAKENING. NOTE THAT SHIPS NOW

DISSIPATES OLAF BY DAY 5...LIKELY DUE TO STRONG SHEAR AND COOLER

SST. THE LATEST IVCN CONSENSUS GUIDANCE SHOWS GRADUAL WEAKENING

DURING THE ENTIRE FORECAST PERIOD. OUR LATEST INTENSITY FORECAST

HAS BEEN ADJUSTED DOWNWARD STARTING IN 24 HOURS...WHICH FOLLOWED

THE MOST RECENT CONSENSUS GUIDANCE AND THE SHIPS OUTPUT.





FORECAST POSITIONS AND MAX WINDS



INIT  22/1500Z 13.5N 146.3W  100 KT 115 MPH

 12H  23/0000Z 14.3N 146.7W  100 KT 115 MPH

 24H  23/1200Z 15.7N 146.9W   95 KT 110 MPH

 36H  24/0000Z 17.4N 146.9W   90 KT 105 MPH

 48H  24/1200Z 18.8N 146.4W   85 KT 100 MPH

 72H  25/1200Z 20.7N 145.0W   65 KT  75 MPH

 96H  26/1200Z 22.5N 142.5W   55 KT  65 MPH

120H  27/1200Z 25.0N 139.0W   45 KT  50 MPH



$$

FORECASTER HOUSTON