WTPA43 PHFO 302110

TCDCP3



HURRICANE IGNACIO DISCUSSION NUMBER  24

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP122015

1100 AM HST SUN AUG 30 2015



THE RECONNAISSANCE AIRCRAFT FOUND MAXIMUM FLIGHT LEVEL WINDS OF 107

KNOTS...A MAXIMUM SFMR WIND OF 94 KT...AND A 961 MB SURFACE

PRESSURE ON THE LAST PASS THROUGH THE EYE. THUS...HAVE LOWERED THE

INTENSITY OF IGNACIO TO 100 KT FOR THIS ADVISORY. THE UW-CIMSS SHEAR

ANALYSIS SHOWS IGNACIO IS NOW EXPERIENCING 15-20 KT OF SOUTHWESTERLY

SHEAR...WHICH IS CONFIRMED ON SATELLITE IMAGERY BY THE RESTRICTED

OUTFLOW IN THAT QUADRANT. RECENT MICROWAVE IMAGERY AND THE RECON

REPORTS SHOW THAT THE RING OF EYEWALL CONVECTION HAS OPENED UP...

AND THE EYE HAS NOW BECOME CLOUD-FILLED ON VISIBLE IMAGERY.



THE INITIAL MOTION IS 325/10. IGNACIO IS ABOUT TO GET ENTANGLED

WITH A WEAK BUT DIGGING UPPER LEVEL TROUGH OVER THE MAIN HAWAIIAN

ISLANDS WHICH WILL CONTINUE TO STEER THE TROPICAL CYCLONE TOWARD

THE NORTHWEST. THE FORECAST TRACK HAS BEEN ADJUSTED TO BE SLIGHTLY

MORE NORTHWARD IN THE SHORT TERM IN THE FACE OF INCREASING

SOUTHWESTERLIES...WITH A BEND BACK TOWARD THE NORTHWEST AFTER 24

HOURS AS IGNACIO BECOMES INCREASINGLY SHEARED. THIS IS A LITTLE TO

THE RIGHT OF THE GUIDANCE CONSENSUS THROUGH 24 HOURS...THEN SHIFTS

TO THE LEFT OF THE CONSENSUS GUIDANCE BY 48 HOURS AND BEYOND. LATE

IN THE FORECAST PERIOD...A STRONGER DIGGING MID-LATITUDE TROUGH FAR

TO THE NORTHWEST OF HAWAII IS EXPECTED TO STEER IGNACIO MORE

NORTHWARD AGAIN.



THE DYNAMIC MODELS SHOW SOUTHWESTERLY SHEAR WILL INCREASE RAPIDLY

OVER IGNACIO OVER THE NEXT 24-48 HOURS...AND THUS RAPID WEAKENING

IS EXPECTED. IT IS INTERESTING THAT IT HAS TAKEN THE SHIPS

STATISTICAL GUIDANCE THIS LONG TO INDICATE THE MAGNITUDE OF SHEAR AS

DEPICTED BY THE DYNAMICAL MODELS FOR A COUPLE OF DAYS NOW. IN ANY

CASE...THE FORECAST HAS BEEN ADJUSTED WEAKER AND IS NOW LOWER THAN

MOST OF THE GUIDANCE SUGGESTS. THE SHEAR MAY WEAKEN A BIT

TEMPORARILY DURING THE DAYS 4-5 TIME FRAME...BUT BY THEN IGNACIO

WILL BE MOVING OVER COOLER WATER.





FORECAST POSITIONS AND MAX WINDS



INIT  30/2100Z 19.0N 149.0W  100 KT 115 MPH

 12H  31/0600Z 20.0N 150.0W   85 KT 100 MPH

 24H  31/1800Z 21.1N 151.1W   70 KT  80 MPH

 36H  01/0600Z 22.1N 152.7W   55 KT  65 MPH

 48H  01/1800Z 23.2N 154.2W   50 KT  60 MPH

 72H  02/1800Z 24.9N 157.1W   45 KT  50 MPH

 96H  03/1800Z 26.9N 160.2W   40 KT  45 MPH

120H  04/1800Z 30.0N 163.0W   40 KT  45 MPH



$$

FORECASTER R BALLARD