WTPA43 PHFO 040840

TCDCP3



HURRICANE IGNACIO DISCUSSION NUMBER  42

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP122015

1100 PM HST THU SEP 03 2015



A PINHOLE EYE DEVELOPED JUST BEFORE THE 0600 UTC ANALYSIS

CYCLE...INCREASING FIX CONFIDENCE. HOWEVER...THE OVERALL SATELLITE

PRESENTATION CONTINUES TO SHOW A SYSTEM UNDER AT LEAST MODERATE

SHEAR STRESS. OUTFLOW IS HINDERED TO THE WEST AND SOUTHWEST...WHILE

DEEP CONVECTION APPEARS TO HAVE COLLAPSED ACROSS MOST OF THE

SOUTHWEST SEMICIRCLE. THE SMALL...10 NM WIDE...EYE LIES JUST WITHIN

THE WESTERN EDGE OF DEEP CONVECTION AND...SINCE 0730 UTC...APPEARS

TO HAVE BEEN SHEARED JUST TO THE NORTHEAST OF WHAT MAY BE AN LLCC.

SATELLITE LOOP SHOWS WHAT MAY BE THE WESTERN AND SOUTHWESTERN FLANK

OF AN LLCC EMERGING FROM THE LAYERED CLOUDS AND DEEP CONVECTION. IF

THIS IS THE TRUE CENTER OF IGNACIO...THEN THE NEXT ADVISORY WILL

HAVE TO ACCOUNT FOR A ONE OR TWO TENTHS OF A DEGREE ADJUSTMENT IN

POSITION TO THE WEST AS WELL AS A MOTION WITH LESS OF A NORTHERLY

COMPONENT. HOWEVER...GIVEN THE HOUR...WE WILL STICK WITH THE PINHOLE

EYE AS THE POSITION FOR THIS ADVISORY. SUBJECTIVE DVORAK SATELLITE

INTENSITY ESTIMATES RANGE FROM 3.5...55 KT...FROM PHFO TO 4.5...77

KT FROM THE UW-CIMSS ADT. JTWC AND SAB SPLIT THE DIFFERENCE AT

4.0...65 KT. GIVEN THE PINHOLE EYE AND CI SPREAD...WE WILL MAKE

IGNACIO A HURRICANE ONCE AGAIN WITH AN INITIAL INTENSITY OF 65 KT.



IGNACIO APPEARS TO BE MOVING ALMOST DUE NORTH...WITH AN INITIAL

MOTION OF 345/11 KT. TRACK AND INTENSITY GUIDANCE REMAIN TIGHTLY

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

AFTERNOON. THIS SYSTEM IS MOVING INTO A WEAKNESS IN THE RIDGE TO ITS

NORTH...SLIDING JUST EAST OF A DEVELOPING FRONTAL SYSTEM. BY 48

HOURS...IGNACIO WILL LIKELY BEGIN TO MERGE WITH THIS

FRONT...BEGINNING EXTRATROPICAL TRANSITION. 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. HOWEVER...INSTEAD OF 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. THE FIVE-DAY FORECAST TRACK ENDS WITH IGNACIO

WEAKENING TO AN EXTRATROPICAL GALE LOW NEAR THE COAST OF BRITISH

COLUMBIA.



THE IGNACIO FORECAST TRACK...INTENSITY...AND WIND RADII FOR DAYS 3

THROUGH 5 WERE COORDINATED WITH THE OCEAN PREDICTION CENTER IN

WASHINGTON D.C.



FORECAST POSITIONS AND MAX WINDS



INIT  04/0900Z 31.5N 163.5W   65 KT  75 MPH

 12H  04/1800Z 33.3N 164.0W   65 KT  75 MPH

 24H  05/0600Z 35.9N 164.4W   65 KT  75 MPH

 36H  05/1800Z 38.8N 164.7W   60 KT  70 MPH

 48H  06/0600Z 42.0N 164.1W   60 KT  70 MPH...BECOMING EXTRATROPICAL

 72H  07/0600Z 46.9N 158.0W   50 KT  60 MPH...POST-TROP/EXTRATROP

 96H  08/0600Z 51.7N 142.5W   45 KT  50 MPH...POST-TROP/EXTRATROP

120H  09/0600Z 53.0N 128.0W   35 KT  40 MPH...POST-TROP/EXTRATROP



$$

FORECASTER POWELL