WTPA33 PHFO 300003
TCPCP3

BULLETIN
HURRICANE IGNACIO INTERMEDIATE ADVISORY NUMBER 20A
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP122015
200 PM HST SAT AUG 29 2015

…POWERFUL HURRICANE IGNACIO CONTINUES TO APPROACH HAWAII…

SUMMARY OF 200 PM HST…0000 UTC…INFORMATION
———————————————-
LOCATION…16.6N 147.3W
ABOUT 550 MI…885 KM ESE OF HILO HAWAII
ABOUT 760 MI…1225 KM ESE OF HONOLULU HAWAII
MAXIMUM SUSTAINED WINDS…135 MPH…215 KM/H
PRESENT MOVEMENT…NW OR 315 DEGREES AT 9 MPH…15 KM/H
MINIMUM CENTRAL PRESSURE…954 MB…28.17 INCHES

WATCHES AND WARNINGS
——————–
CHANGES WITH THIS ADVISORY…

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT…

A TROPICAL STORM WATCH IS IN EFFECT FOR…
* HAWAII COUNTY

A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA…GENERALLY WITHIN 48 HOURS.

INTERESTS ELSEWHERE IN THE MAIN HAWAIIAN ISLANDS SHOULD CONTINUE TO
CLOSELY MONITOR THE PROGRESS OF IGNACIO. WATCHES MAY BE REQUIRED
FOR ADDITIONAL ISLANDS LATER TODAY OR TONIGHT.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA…PLEASE MONITOR
PRODUCTS ISSUED BY THE NATIONAL WEATHER SERVICE OFFICE IN
HONOLULU HAWAII.

DISCUSSION AND 48-HOUR OUTLOOK
——————————
AT 200 PM HST…0000 UTC…THE EYE OF HURRICANE IGNACIO WAS
LOCATED NEAR LATITUDE 16.6 NORTH…LONGITUDE 147.3 WEST. IGNACIO IS
MOVING TOWARD THE NORTHWEST NEAR 9 MPH…15 KM/H…AND THIS MOTION
IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS. ON THE FORECAST
TRACK…IGNACIO WILL BE PASSING NORTHEAST OF THE BIG ISLAND ON
MONDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 135 MPH…215 KM/H…WITH HIGHER
GUSTS. IGNACIO IS A CATEGORY FOUR HURRICANE ON THE SAFFIR-SIMPSON
HURRICANE WIND SCALE. SOME ADDITIONAL STRENGTHENING IS STILL
POSSIBLE TODAY BEFORE A WEAKENING TREND BEGINS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 30 MILES…45 KM…FROM
THE CENTER…AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 140
MILES…220 KM.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 954 MB…28.17 INCHES.

HAZARDS AFFECTING LAND
———————-
WIND…TROPICAL STORM CONDITIONS ARE POSSIBLE ON THE BIG ISLAND OF
HAWAII STARTING SUNDAY NIGHT.

RAINFALL…TOTAL RAINFALL AMOUNTS OF 2 TO 4 INCHES…WITH ISOLATED
MAXIMUM AMOUNTS NEAR 6 INCHES MAINLY IN AREAS OF HIGHER TERRAIN…
ARE POSSIBLE IN THE WATCH AREA.

SURF…LARGE SWELLS GENERATED BY IGNACIO WILL ARRIVE ALONG EAST
AND SOUTHEAST FACING SHORES OF THE MAIN HAWAIIAN ISLANDS OVER THE
NEXT SEVERAL DAYS. RESULTANT SURF WILL BE LARGE AND POTENTIALLY
LIFE-THREATENING…ESPECIALLY ON THE BIG ISLAND LATER THIS WEEKEND
AND EARLY NEXT WEEK.

NEXT ADVISORY
————-
NEXT COMPLETE ADVISORY…500 PM HST.

$$
FORECASTER R BALLARD



WTPA43 PHFO 292118
TCDCP3

HURRICANE IGNACIO DISCUSSION NUMBER 20
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP122015
1100 AM HST SAT AUG 29 2015

IGNACIO HAS A VERY IMPRESSIVE SATELLITE PRESENTATION THIS MORNING
WITH A 20 NM WARM…CLEAR EYE. THE RECONNAISSANCE AIRCRAFT FOUND 133
KT FLIGHT LEVEL WINDS IN THE NORTHEAST QUADRANT OF IGNACIO…WITH
SFMR WINDS PEAKING AT 121 KT. BASED ON THIS INFORMATION THE ADVISORY
INTENSITY HAS BEEN SET TO 120 KT…THE SECOND CATEGORY FOUR
HURRICANE IN THE CENTRAL PACIFIC BASIN OF 2015…AND THE THIRD MAJOR
HURRICANE FOR THE YEAR. THE WIND RADII HAVE BEEN ADJUSTED ONCE AGAIN
TO FIT THE NEW AIRCRAFT DATA.

THE HURRICANE IS MOVING TOWARD THE NORTHWEST…315 DEGREES…AT 8
KNOTS. OUR FORECAST PHILOSOPHY HAS NOT CHANGED…AS IGNACIO
CONTINUES TO MOVE STEADILY NORTHWEST TOWARD A BREAK IN THE
MID-LEVEL RIDGE. THIS MOTION IS EXPECTED TO CONTINUE FOR THE NEXT
COUPLE OF DAYS AND THE TRACK GUIDANCE IS TIGHTLY CLUSTERED AROUND
THIS IDEA. LATER IN THE FORECAST PERIOD…BEYOND DAY 3…SOME OF
THE GUIDANCE SHOWS A SLIGHT BEND TOWARD THE WEST AS THE SYSTEM
BEGINS TO ENCOUNTER SHEAR FROM THE SUBTROPICAL JET AS WELL AS A
WEAK UPPER LEVEL TROUGH OVER THE MAIN HAWAIIAN ISLANDS. OUR
FORECAST IS SLIGHTLY TO THE RIGHT OF THE PREVIOUS FORECAST AND CLOSE
TO THE CONSENSUS GUIDANCE THROUGH 72 HOURS OWING TO THE INITIAL
MORE NORTHWARD MOTION…AND SLIGHTLY TO THE LEFT OF THE PREVIOUS
FORECAST AT DAYS 4 AND 5.

IGNACIO IS CURRENTLY AT THE NORTHERN EDGE OF AN AREA OF WEAK SHEAR
UNDERNEATH AN UPPER LEVEL RIDGE. SEA SURFACE TEMPERATURES ALONG
THE FORECAST TRACK FROM NASA-SPORT ARE 27-28C. THE HURRICANE HAS
A VERY SMALL WINDOW TO INTENSIFY FURTHER TODAY…BUT AS IT CONTINUES
NORTHWEST IT WILL BEGIN ENCOUNTERING UPPER LEVEL WESTERLIES THAT
WILL START TO INDUCE WEAKENING. OUR FORECAST STAYS CLOSE TO THE
SHIPS GUIDANCE THROUGH THE NEXT 24 HOURS…THEN SHOWS WEAKENING AT A
SLIGHTLY MORE GRADUAL TREND THAN SHIPS THROUGH THE REST OF THE
FORECAST PERIOD. IT IS POSSIBLE THAT IGNACIO COULD WEAKEN FASTER
BEYOND 48 HOURS IF THE STRONG SHEAR DEPICTED IN THE GLOBAL MODELS
MATERIALIZES.

FORECAST POSITIONS AND MAX WINDS

INIT 29/2100Z 16.4N 146.9W 120 KT 140 MPH
12H 30/0600Z 17.3N 147.9W 125 KT 145 MPH
24H 30/1800Z 18.6N 149.3W 115 KT 135 MPH
36H 31/0600Z 19.6N 150.8W 105 KT 120 MPH
48H 31/1800Z 20.6N 152.3W 95 KT 110 MPH
72H 01/1800Z 22.5N 155.1W 80 KT 90 MPH
96H 02/1800Z 24.5N 158.0W 70 KT 80 MPH
120H 03/1800Z 26.4N 161.2W 65 KT 75 MPH

$$
FORECASTER R BALLARD