WTPA43 PHFO 032056

TCDCP3



TROPICAL STORM IGNACIO DISCUSSION NUMBER  40

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP122015

1100 AM HST THU SEP 03 2015



THE INNER CORE STRUCTURE OF IGNACIO IS STARTING TO DETERIORATE ONCE

AGAIN...AS SHOWN BY AN SSMI PASS AT 1408 UTC AND AN SSMI/S AT 1456

UTC. SINCE THEN...THE SHORT-LIVED INTERMITTENT EYE FEATURE HAS

FILLED ONCE AGAIN. THE CURRENT INTENSITY ESTIMATES WERE 3.0 FROM

UW-CIMSS ADT...3.5 FROM SAB AND JTWC...AND 4.0 AT PHFO. HAVE

LOWERED IGNACIO BACK TO 60 KT FOR THIS ADVISORY BASED ON A CONSENSUS

OF THESE ESTIMATES.



THE INITIAL MOTION ESTIMATE IS 320/11...BUT THERE IS SOME

UNCERTAINTY AS TO WHETHER OR NOT THIS IS THE BEGINNING OF THE

ANTICIPATED NORTHWARD TURN...OR A TEMPORARY WOBBLE. THERE IS NO

SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY OF THE PAST FEW

DAYS...AND THE TRACK AND INTENSITY GUIDANCE IS IN GOOD AGREEMENT FOR

MOST OF THE FORECAST. OVER THE NEXT DAY OR SO...A SHORTWAVE TROUGH

TO THE NORTHWEST OF THE CYCLONE WILL PICK UP THE SYSTEM AND DRIVE IT

NORTHWARD TOWARD HIGHER LATITUDES. AS IT GAINS LATITUDE...IT WILL

ENCOUNTER STRONGER WESTERLIES WHICH WILL PROPEL IT EASTWARD ACROSS

THE CHILLY WATERS OF THE NORTH PACIFIC. SHEAR IS EXPECTED TO REMAIN

MODERATE FOR THE NEXT DAY OR SO...AND THE SEA SURFACE TEMPERATURES

ONLY GRADUALLY DECREASE...SO IGNACIO IS EXPECTED TO MAINTAIN

INTENSITY OR ONLY VERY SLOWLY SPIN DOWN IN THE FIRST 48 HOURS.

AFTERWARD...BAROCLINIC INFLUENCES MAY HELP TO SUSTAIN THE SYSTEM AS

EXTRATROPICAL TRANSITION IS EXPECTED WITH IGNACIO MOVING OVER

SUB-20C SEA SURFACE TEMPERATURES. AT DAYS 4 AND 5 THE FORECAST

TRACK IS TO THE RIGHT OF THE CONSENSUS GUIDANCE AND MORE IN LINE

WITH THE ECMWF GUIDANCE.



FORECAST TRACK...INTENSITY...AND RADII FOR DAYS 3 THROUGH 5 WERE

COORDINATED WITH THE OCEAN PREDICTION CENTER IN WASHINGTON D.C.





FORECAST POSITIONS AND MAX WINDS



INIT  03/2100Z 29.4N 162.5W   60 KT  70 MPH

 12H  04/0600Z 30.7N 163.7W   60 KT  70 MPH

 24H  04/1800Z 33.2N 164.4W   60 KT  70 MPH

 36H  05/0600Z 36.1N 164.8W   60 KT  70 MPH

 48H  05/1800Z 39.1N 164.9W   55 KT  65 MPH

 72H  06/1800Z 44.6N 163.5W   50 KT  60 MPH...BECOMING EXTRATROPICAL

 96H  07/1800Z 49.2N 152.5W   45 KT  50 MPH...POST-TROP/EXTRATROP

120H  08/1800Z 52.5N 137.0W   40 KT  45 MPH...POST-TROP/EXTRATROP



$$

FORECASTER R BALLARD