WTPA43 PHFO 272039

TCDCP3



HURRICANE IGNACIO DISCUSSION NUMBER  12

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP122015

1100 AM HST THU AUG 27 2015



HURRICANE IGNACIO PASSED WEST OF 140W LONGITUDE SHORTLY AFTER 1500

UTC...MAKING IT THE EIGHTH TROPICAL CYCLONE IN THE CENTRAL NORTH

PACIFIC BASIN FOR THE 2015 HURRICANE SEASON. IGNACIO CONTINUES TO

HAVE A CLOUD-FILLED EYE WITH PERSISTENT CLOUD TOPS COLDER THAN -80C

AND AN OVERALL SYMMETRIC OUTFLOW. A 1642 UTC SSMI/S PASS AND

LIGHTNING DATA SHOWED THAT THE MOST ACTIVE DEEP CONVECTION HAS BEEN

OCCURRING SOUTH AND SOUTHWEST OF THE CENTER. DVORAK INTENSITY

ESTIMATES CAME IN AT 77 KT FROM SAB AND JTWC...AND 90 KT FROM PHFO.

A 1730 UTC CIMSS ADT ESTIMATE WAS CLOSE TO 80 KT. BASED ON A BLEND

OF THESE DATA...THE INITIAL INTENSITY FOR THIS ADVISORY WILL BE HELD

AT 80 KT.



IGNACIO IS MOVING AT 280/11 KT AND APPEARS TO HAVE MOVED A BIT LEFT

OF THE PREVIOUS FORECAST TRACK. DESPITE THIS SLIGHT WOBBLE...THE

GENERAL TRACK FORECAST REMAINS UNCHANGED WITH A SUBTROPICAL RIDGE TO

THE NORTH OF THE CYCLONE CONTINUING TO STEER IT TOWARD THE

WEST-NORTHWEST...THOUGH WITH A SLOWER FORWARD MOTION STARTING LATER

TODAY OR TONIGHT. FOR THIS FORECAST PACKAGE...THE DYNAMICAL

GUIDANCE SPREAD HAS BECOME TIGHTER...WITH THE ECMWF HAVING SHIFTED

NORTH TO LINE UP CLOSER WITH THE GFS. THE SHIFT APPEARS TO BE DUE TO

THE ECMWF SHOWING A STRONGER CYCLONE WITH LESS WEAKENING DUE TO

VERTICAL WIND SHEAR. THE CURRENT FORECAST IS CLOSE TO THE PREVIOUS

FORECAST AND MODEL CONSENSUS THROUGH 72 HOURS...THEN NUDGED

NORTHWARD CLOSER TO THE GFS AND ECMWF FOR 96 AND 120 HOURS.



THE HURRICANE SHOULD REMAIN OVER WARM SEA SURFACE TEMPERATURES AND

LIGHT TO MODERATE VERTICAL WIND SHEAR DURING THE NEXT COUPLE OF

DAYS. VERTICAL WIND SHEAR IS EXPECTED TO INCREASE AFTER 72

HOURS...WHICH SHOULD BEGIN A GRADUAL WEAKENING. THE INTENSITY

FORECAST FOR THIS PACKAGE IS CLOSE TO THE PREVIOUS FORECAST AND

GRADUALLY STRENGTHENS IGNACIO TO A MAJOR HURRICANE OVER THE NEXT 24

TO 48 HOURS...FOLLOWED BY GRADUAL WEAKENING AFTERWARD. THIS IS CLOSE

TO THE IVCN CONSENSUS THROUGH 48 HOURS...THEN SLIGHTLY BELOW IT FROM

72 HOURS THROUGH THE END OF THE FORECAST PERIOD.





FORECAST POSITIONS AND MAX WINDS



INIT  27/2100Z 12.9N 140.8W   80 KT  90 MPH

 12H  28/0600Z 13.6N 142.3W   85 KT 100 MPH

 24H  28/1800Z 14.5N 144.2W   95 KT 110 MPH

 36H  29/0600Z 15.3N 145.7W  100 KT 115 MPH

 48H  29/1800Z 16.1N 147.1W  100 KT 115 MPH

 72H  30/1800Z 17.5N 149.9W   90 KT 105 MPH

 96H  31/1800Z 19.5N 152.5W   80 KT  90 MPH

120H  01/1800Z 21.0N 154.5W   70 KT  80 MPH



$$

FORECASTER KODAMA