WTPA43 PHFO 041440

TCDCP3



HURRICANE IGNACIO DISCUSSION NUMBER  43

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP122015

500 AM HST FRI SEP 04 2015



ANIMATION SHOWS THE LLCC LIKELY REMAINS JUST ALONG THE SOUTHERN EDGE

OF DEEPEST CONVECTION...MAKING EARLIER FIX CONFIDENCE DEPENDENT ON A

PINHOLE EYE FEATURE A GOOD BET. IGNACIO DOES NOT HAVE THE SATELLITE

PRESENTATION OF A HEALTHY TROPICAL SYSTEM. DEEP CONVECTION AND

ALMOST ALL ASSOCIATED LAYERED CLOUDS HAVE BEEN DISPLACED NORTH AND

NORTHEAST OF THE LLCC BY SOUTHWEST SHEAR RANGING FROM 11

KT...ACCORDING TO SHIPS...TO 25 KT...ACCORDING TO UW-CIMSS. THE

NORTHWEST EDGE OF THE LAYERED CLOUD CANOPY IS BEGINNING TO MERGE

WITH CLOUDS ASSOCIATED WITH A FRONTAL BOUNDARY. SUBJECTIVE DVORAK

SATELLITE INTENSITY ESTIMATES ARE UNCHANGED FROM LAST TIME...RANGING

FROM 3.5...55 KT...FROM PHFO TO 4.5...77 KT...FROM UW-CIMSS ADT.

JTWC AND SAB ONCE AGAIN TAKE THE MIDDLE GROUND WITH 4.0...65 KT.

GIVEN THIS CI SPREAD...WE WILL KEEP 65 KT AS THE INITIAL INTENSITY

FOR THIS ADVISORY.



IGNACIO CONTINUES MOVING AT A STEADY RATE TOWARD THE NORTH

NORTHWEST...OR 335/11 KT. TRACK AND INTENSITY GUIDANCE REMAIN

TIGHTLY CLUSTERED...AND FORECAST PHILOSOPHY HAS NOT CHANGED SINCE

LAST EVENING. THE FORECAST TRACK IS THEREFORE PRETTY MUCH UNCHANGED

AS THIS SYSTEM MOVES INTO A WEAKNESS IN THE RIDGE TO ITS NORTH.

BETWEEN 36 AND 48 HOURS...WHATEVER IS LEFT OF THE CORE OF IGNACIO

WILL BEGIN TO MERGE WITH THE FRONT PRESSING IN FROM ITS WEST. THE

MID-LEVEL TROUGH SUPPORTING THE FRONT WILL THEN DRIVE IGNACIO

FARTHER NORTHWARD AND STRENGTHENING WESTERLIES WILL CAUSE AN

INCREASE IN FORWARD SPEED TOWARD THE NORTHEAST. INSTEAD OF

IMMEDIATELY DISSIPATING...IGNACIO WILL BENEFIT FROM INCREASING

BAROCLINIC EFFECTS THE FARTHER NORTH IT GOES...RESULTING IN COMPLETE

TRANSITION TO AN EXTRATROPICAL STORM LOW AT 72 HOURS. IGNACIO IS

THEN FORECAST TO GRADUALLY WEAKEN AS IT RACES NORTHEASTWARD TOWARD

THE MAINLAND...DISSIPATING BY DAY FIVE OVER BRITISH COLUMBIA.



THE IGNACIO FORECAST TRACK...INTENSITY...AND WIND RADII FOR DAYS

THREE AND FOUR...AND DISSIPATION ON DAY FIVE...WERE COORDINATED WITH

THE OCEAN PREDICTION CENTER IN WASHINGTON D.C.



FORECAST POSITIONS AND MAX WINDS



INIT  04/1500Z 32.4N 164.2W   65 KT  75 MPH

 12H  05/0000Z 34.2N 164.8W   65 KT  75 MPH

 24H  05/1200Z 36.9N 165.3W   60 KT  70 MPH

 36H  06/0000Z 39.9N 164.7W   60 KT  70 MPH

 48H  06/1200Z 42.7N 163.0W   55 KT  65 MPH...BECOMING EXTRATROPICAL

 72H  07/1200Z 47.0N 157.7W   55 KT  65 MPH...POST-TROP/EXTRATROP

 96H  08/1200Z 50.6N 141.4W   40 KT  45 MPH...POST-TROP/EXTRATROP

120H  09/1200Z...DISSIPATED



$$

FORECASTER POWELL