WTPA43 PHFO 292118

TCDCP3



HURRICANE IGNACIO DISCUSSION NUMBER  20

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP122015

1100 AM HST SAT AUG 29 2015



IGNACIO HAS A VERY IMPRESSIVE SATELLITE PRESENTATION THIS MORNING

WITH A 20 NM WARM...CLEAR EYE. THE RECONNAISSANCE AIRCRAFT FOUND 133

KT FLIGHT LEVEL WINDS IN THE NORTHEAST QUADRANT OF IGNACIO...WITH

SFMR WINDS PEAKING AT 121 KT. BASED ON THIS INFORMATION THE ADVISORY

INTENSITY HAS BEEN SET TO 120 KT...THE SECOND CATEGORY FOUR

HURRICANE IN THE CENTRAL PACIFIC BASIN OF 2015...AND THE THIRD MAJOR

HURRICANE FOR THE YEAR. THE WIND RADII HAVE BEEN ADJUSTED ONCE AGAIN

TO FIT THE NEW AIRCRAFT DATA.



THE HURRICANE IS MOVING TOWARD THE NORTHWEST...315 DEGREES...AT 8

KNOTS. OUR FORECAST PHILOSOPHY HAS NOT CHANGED...AS IGNACIO

CONTINUES TO MOVE STEADILY NORTHWEST TOWARD A BREAK IN THE

MID-LEVEL RIDGE. THIS MOTION IS EXPECTED TO CONTINUE FOR THE NEXT

COUPLE OF DAYS AND THE TRACK GUIDANCE IS TIGHTLY CLUSTERED AROUND

THIS IDEA. LATER IN THE FORECAST PERIOD...BEYOND DAY 3...SOME OF

THE GUIDANCE SHOWS A SLIGHT BEND TOWARD THE WEST AS THE SYSTEM

BEGINS TO ENCOUNTER SHEAR FROM THE SUBTROPICAL JET AS WELL AS A

WEAK UPPER LEVEL TROUGH OVER THE MAIN HAWAIIAN ISLANDS. OUR

FORECAST IS SLIGHTLY TO THE RIGHT OF THE PREVIOUS FORECAST AND CLOSE

TO THE CONSENSUS GUIDANCE THROUGH 72 HOURS OWING TO THE INITIAL

MORE NORTHWARD MOTION...AND SLIGHTLY TO THE LEFT OF THE PREVIOUS

FORECAST AT DAYS 4 AND 5.



IGNACIO IS CURRENTLY AT THE NORTHERN EDGE OF AN AREA OF WEAK SHEAR

UNDERNEATH AN UPPER LEVEL RIDGE. SEA SURFACE TEMPERATURES ALONG

THE FORECAST TRACK FROM NASA-SPORT ARE 27-28C. THE HURRICANE HAS

A VERY SMALL WINDOW TO INTENSIFY FURTHER TODAY...BUT AS IT CONTINUES

NORTHWEST IT WILL BEGIN ENCOUNTERING UPPER LEVEL WESTERLIES THAT

WILL START TO INDUCE WEAKENING. OUR FORECAST STAYS CLOSE TO THE

SHIPS GUIDANCE THROUGH THE NEXT 24 HOURS...THEN SHOWS WEAKENING AT A

SLIGHTLY MORE GRADUAL TREND THAN SHIPS THROUGH THE REST OF THE

FORECAST PERIOD. IT IS POSSIBLE THAT IGNACIO COULD WEAKEN FASTER

BEYOND 48 HOURS IF THE STRONG SHEAR DEPICTED IN THE GLOBAL MODELS

MATERIALIZES.





FORECAST POSITIONS AND MAX WINDS



INIT  29/2100Z 16.4N 146.9W  120 KT 140 MPH

 12H  30/0600Z 17.3N 147.9W  125 KT 145 MPH

 24H  30/1800Z 18.6N 149.3W  115 KT 135 MPH

 36H  31/0600Z 19.6N 150.8W  105 KT 120 MPH

 48H  31/1800Z 20.6N 152.3W   95 KT 110 MPH

 72H  01/1800Z 22.5N 155.1W   80 KT  90 MPH

 96H  02/1800Z 24.5N 158.0W   70 KT  80 MPH

120H  03/1800Z 26.4N 161.2W   65 KT  75 MPH



$$

FORECASTER R BALLARD