WTPA43 PHFO 290309

TCDCP3



HURRICANE IGNACIO DISCUSSION NUMBER  17

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP122015

500 PM HST FRI AUG 28 2015



A BANDING EYE FEATURE DEVELOPED IN THE VISIBLE IMAGERY AT 2200

UTC...LENDING ADDITIONAL CONFIDENCE IN THE CENTER POSITION FOR

ADVISORY TIME. THE EYE FEATURE HAS SINCE FILLED IN ONCE AGAIN.

DVORAK INTENSITY ESTIMATES WERE 4.5 FROM PHFO AND SAB AND 5.0 FROM

JTWC...SO THE INTENSITY YET AGAIN WILL BE SET TO 80 KT...UNCHANGED

OVER THE PAST 36 HOURS. AN AIR FORCE RESERVE RECONNAISSANCE UNIT IS

SCHEDULED TO INVESTIGATE IGNACIO AT 0600 UTC...WHICH WILL HELP TO

ASCERTAIN THE ACTUAL SIZE AND INTENSITY OF THE HURRICANE.



THE INITIAL MOTION REMAINS A STEADY 305/7. THE FORECAST PHILOSOPHY

IS UNCHANGED...WITH IGNACIO SLOWLY MARCHING NORTHWEST TOWARD A

WEAKNESS IN A MID-LEVEL RIDGE FOR THE NEXT SEVERAL DAYS. ONCE AGAIN

THE TRACK GUIDANCE REMAINS TIGHTLY CLUSTERED...BUT THERE ARE SOME

NOTEWORTHY OUTLIERS THAT BRING IGNACIO A LITTLE FARTHER TO THE LEFT

THAN THE CONSENSUS. THE LEFT-MOST OUTLIERS ARE CERTAINLY PLAUSIBLE

SOLUTIONS...PARTICULARLY IF WIND SHEAR LATER IN THE FORECAST PERIOD

IMPACTS IGNACIO MORE THAN MOST OF THE DYNAMICAL GUIDANCE IS

INDICATING.



DESPITE BEING IN AN ENVIRONMENT OF WEAK SHEAR AND WARM OCEAN

TEMPERATURES...IGNACIO HAS BEEN STUBBORN TO INTENSIFY THUS FAR.

ALTHOUGH IT IS DIFFICULT TO BE CERTAIN WHY...THE CIMSS MIMIC-TOTAL

PRECIPITABLE WATER AS WELL AS VISIBLE SATELLITE IMAGERY SHOWED A

RIBBON OF DRY AIR THAT APPEARS TO HAVE BEEN PULLED INTO THE CORE

CIRCULATION OF THE CYCLONE. IF IGNACIO CAN OVERCOME THIS...THE

ENVIRONMENT STILL SEEMS TO FAVOR SOME INTENSIFICATION OVER THE

NEXT 24-36 HOURS BEFORE SOUTHWESTERLY SHEAR STARTS TO INCREASE.

THERE IS GOOD AGREEMENT IN THE GLOBAL MODELS REGARDING THIS

SHEAR...WHICH SHOULD INDUCE STEADY WEAKENING AFTER 48 HOURS. THE

STATISTICAL GUIDANCE SHOWS A MORE RAPID WEAKENING TREND AND SHIPS

HAS NOW COME INTO BETTER AGREEMENT WITH OUR OFFICIAL FORECAST. THE

DYNAMICAL MODELS HOLD IGNACIO STRONGER...BUT THIS SEEMS UNLIKELY

GIVEN THE SHEAR THEY ARE DEPICTING.





FORECAST POSITIONS AND MAX WINDS



INIT  29/0300Z 15.2N 145.2W   80 KT  90 MPH

 12H  29/1200Z 15.9N 146.3W   85 KT 100 MPH

 24H  30/0000Z 16.8N 147.8W   90 KT 105 MPH

 36H  30/1200Z 17.7N 149.3W   90 KT 105 MPH

 48H  31/0000Z 18.6N 150.6W   85 KT 100 MPH

 72H  01/0000Z 20.5N 153.4W   75 KT  85 MPH

 96H  02/0000Z 22.6N 155.9W   70 KT  80 MPH

120H  03/0000Z 24.7N 158.3W   60 KT  70 MPH



$$

FORECASTER R BALLARD