WTPA33 PHFO 290241
TCPCP3

BULLETIN
HURRICANE IGNACIO ADVISORY NUMBER 17
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP122015
500 PM HST FRI AUG 28 2015

…IGNACIO MARCHING NORTHWESTWARD AND CONTINUES TO GET CLOSER TO
HAWAII…

SUMMARY OF 500 PM HST…0300 UTC…INFORMATION
———————————————-
LOCATION…15.2N 145.2W
ABOUT 720 MI…1160 KM ESE OF HILO HAWAII
ABOUT 935 MI…1500 KM ESE OF HONOLULU HAWAII
MAXIMUM SUSTAINED WINDS…90 MPH…150 KM/H
PRESENT MOVEMENT…NW OR 305 DEGREES AT 8 MPH…13 KM/H
MINIMUM CENTRAL PRESSURE…981 MB…28.97 INCHES

WATCHES AND WARNINGS
——————–
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE MAIN HAWAIIAN ISLANDS SHOULD CONTINUE TO CLOSELY
MONITOR THE PROGRESS OF IGNACIO. A WATCH MAY BE ISSUED FOR PORTIONS
OF THE MAIN HAWAIIAN ISLANDS OVERNIGHT OR EARLY SATURDAY.

DISCUSSION AND 48-HOUR OUTLOOK
——————————
AT 500 PM HST…0300 UTC…THE CENTER OF HURRICANE IGNACIO WAS
LOCATED NEAR LATITUDE 15.2 NORTH…LONGITUDE 145.2 WEST. IGNACIO IS
MOVING TOWARD THE NORTHWEST NEAR 8 MPH…13 KM/H…AND THIS MOTION
IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS.

MAXIMUM SUSTAINED WINDS ARE NEAR 90 MPH…150 KM/H…WITH HIGHER
GUSTS. SOME ADDITIONAL STRENGTHENING IS STILL POSSIBLE OVER THE
NEXT DAY OR SO…FOLLOWED BY A WEAKENING TREND WHICH IS EXPECTED TO
BEGIN ON SUNDAY.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 25 MILES…35 KM…FROM
THE CENTER…AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 80
MILES…130 KM.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 981 MB…28.97 INCHES.

HAZARDS AFFECTING LAND
———————-
SURF…SURF FROM IGNACIO WILL BEGIN TO BUILD ALONG EAST FACING
SHORES OF THE BIG ISLAND THIS WEEKEND…AND MAY BECOME VERY LARGE
AND DANGEROUS BY LATE SUNDAY.

NEXT ADVISORY
————-
NEXT COMPLETE ADVISORY…1100 PM HST.

$$
FORECASTER R BALLARD



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