WTPA43 PHFO 010311

TCDCP3



HURRICANE IGNACIO DISCUSSION NUMBER  29

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP122015

500 PM HST MON AUG 31 2015



THE FINAL U.S. AIR FORCE RESERVE RECONNAISSANCE MISSION FOR IGNACIO

FOUND MAXIMUM FLIGHT LEVEL WINDS OF 100 KNOTS...AS WELL AS A MAXIMUM

SFMR WIND OF 83 KNOTS IN THE CONVECTIVELY ACTIVE NORTHWEST QUADRANT.

THE SURFACE PRESSURE HAD RISEN SEVERAL MILLIBARS FROM EARLY THIS

MORNING...UP TO 973 MB. BASED ON THESE DATA...HAVE LOWERED THE

ADVISORY INTENSITY SLIGHTLY TO 85 KT. THE HURRICANE IS TRAVERSING A

ZONE OF NEARLY 30 KNOTS OF SHEAR AS CALCULATED FROM THE LIHUE AND

HILO SOUNDINGS AND IN AGREEMENT WITH THE UW-CIMSS ANALYSIS. DESPITE

THIS...IGNACIO IS DOING ITS BEST TO FIGHT OFF THE EFFECTS OF THIS

SHEAR...AS THE AIRCRAFT STILL FOUND AN ELLIPTICAL 30 NM WIDE EYE ON

THE LONG AXIS. THE EYE WAS STILL FAINTLY DISCERNIBLE IN VISIBLE

IMAGERY LATE THIS AFTERNOON.



THE HURRICANE IS MOVING TOWARD THE NORTHWEST...310 DEGREES...AT 10

KT. THERE IS VERY LITTLE CHANGE TO THE FORECAST TRACK AS IGNACIO

HEADS NORTHWEST FOR THE NEXT FEW DAYS TOWARD A WEAK MID-LEVEL

TROUGH LOCATED TO THE NORTH OF FRENCH FRIGATE SHOALS. AFTER 3

DAYS...A TURN MORE TOWARD THE NORTH IS EXPECTED AS A STRONG

DIGGING MID-LATITUDE TROUGH BEGINS TO SCOOP UP IGNACIO. MOST OF THE

TRACK GUIDANCE REMAINS VERY TIGHTLY CLUSTERED ON OUR OFFICIAL

FORECAST THROUGH 5 DAYS...ALTHOUGH THE GFS IS A NOTEWORTHY OUTLIER

ON THE WEST SIDE OF THE GUIDANCE ENVELOPE BY DAY 3 AND BEYOND.



IGNACIO IS DOING A REMARKABLE JOB OF MAINTAINING AN INNER CORE IN

THE FACE OF THIS SHEAR. THIS MAY BE DUE TO THE ANOMALOUSLY WARM...2

TO 3C ABOVE NORMAL...SEA SURFACE TEMPERATURES IT IS CURRENTLY

TRAVERSING. THE MODERATE SOUTHWESTERLY SHEAR IS EXPECTED TO

CONTINUE ALONG THE FORECAST TRACK FOR THE NEXT 48 HOURS...LEADING

TO CONTINUED GRADUAL WEAKENING. AFTER THAT...IGNACIO MAY

TEMPORARILY WIND UP IN A ZONE OF WEAKER SHEAR WELL TO THE

NORTH-NORTHWEST OF HAWAII. AT DAYS 4 AND 5...IGNACIO MAY BEGIN TO

FEEL SOME BAROCLINIC INFLUENCE FROM THE EXTRATROPICAL TROUGH...AND

THE GLOBAL MODELS REFLECT THIS BY MAINTAINING IGNACIO AT HURRICANE

STRENGTH THROUGH THE END OF THE FORECAST PERIOD. HOWEVER...BY THEN

THE SYSTEM WILL BE OVER SEA SURFACE TEMPERATURES NEAR 24C AND SO

IT WILL VERY LIKELY START TO LOSE TROPICAL CHARACTERISTICS AT THAT

TIME. OUR FORECAST...WHICH IS SIMILAR TO THE PREVIOUS ADVISORY BUT

HAS A HIGH AMOUNT OF UNCERTAINTY...SHOWS SOMEWHAT MORE WEAKENING AND

IS MORE IN LINE WITH THE INTENSITY CONSENSUS.





FORECAST POSITIONS AND MAX WINDS



INIT  01/0300Z 22.2N 152.3W   85 KT 100 MPH

 12H  01/1200Z 23.0N 153.4W   80 KT  90 MPH

 24H  02/0000Z 24.2N 154.9W   70 KT  80 MPH

 36H  02/1200Z 25.1N 156.5W   65 KT  75 MPH

 48H  03/0000Z 26.2N 158.1W   60 KT  70 MPH

 72H  04/0000Z 28.8N 161.7W   60 KT  70 MPH

 96H  05/0000Z 32.3N 163.5W   60 KT  70 MPH

120H  06/0000Z 37.3N 164.5W   60 KT  70 MPH



$$

R BALLARD