WTPA35 PHFO 092037
TCPCP5

BULLETIN
HURRICANE HILDA ADVISORY NUMBER 16
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP102015
1100 AM HST SUN AUG 09 2015

…HILDA WEAKENS SLIGHTLY BUT CONTINUES TO MOVE TOWARD THE HAWAIIAN
ISLANDS…

SUMMARY OF 1100 AM HST…2100 UTC…INFORMATION
———————————————–
LOCATION…15.0N 147.4W
ABOUT 600 MI…970 KM ESE OF HILO HAWAII
ABOUT 815 MI…1310 KM ESE OF HONOLULU HAWAII
MAXIMUM SUSTAINED WINDS…110 MPH…175 KM/H
PRESENT MOVEMENT…WNW OR 295 DEGREES AT 10 MPH…17 KM/H
MINIMUM CENTRAL PRESSURE…964 MB…28.47 INCHES

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

INTERESTS IN THE MAIN HAWAIIAN ISLANDS SHOULD MONITOR THE PROGRESS
OF HILDA.

DISCUSSION AND 48-HOUR OUTLOOK
——————————
AT 1100 AM HST…2100 UTC…THE CENTER OF HURRICANE HILDA WAS
LOCATED NEAR LATITUDE 15.0 NORTH…LONGITUDE 147.4 WEST. HILDA IS
MOVING TOWARD THE WEST-NORTHWEST NEAR 10 MPH…17 KM/H. HILDA IS
FORECAST TO GRADUALLY TURN TOWARD THE NORTHWEST AND MOVE SLIGHTLY
MORE SLOWLY OVER THE NEXT 48 HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 110 MPH…175 KM/H…WITH HIGHER
GUSTS. HILDA IS FORECAST TO CONTINUE WEAKENING OVER THE NEXT 48
HOURS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 25 MILES…35 KM…FROM
THE CENTER…AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 90
MILES…150 KM.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 964 MB…28.47 INCHES.

HAZARDS AFFECTING LAND
———————-
SURF…SWELLS ASSOCIATED WITH HURRICANE HILDA WILL PRODUCE LARGE
SURF ALONG EAST AND SOUTHEAST FACING SHORES OF THE MAIN HAWAIIAN
ISLANDS OVER THE NEXT COUPLE OF DAYS.

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

$$
FORECASTER DONALDSON



WTPA45 PHFO 092108
TCDCP5

HURRICANE HILDA DISCUSSION NUMBER 16
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP102015
1100 AM HST SUN AUG 09 2015

SATELLITE FIXES FROM HFO…SAB AND JTWC WERE IN GOOD AGREEMENT ON
BOTH LOCATION AND INTENSITY FOR HURRICANE HILDA. I HAVE SET THE
INITIAL INTENSITY AT 95 KT. THE SATELLITE SIGNATURE OF THE
HURRICANE SHOWS IT HAS WEAKENED OVER THE PAST 24 HOURS. THE
EYE IS NO LONGER WELL-DEFINED. HILDA IS EXPECTED TO CONTINUE SLOWLY
WEAKENING DUE TO WEAK SOUTHWEST SHEAR AND DECREASING SEA SURFACE
TEMPERATURES.

HILDA CONTINUES TO MOVE TOWARD THE WEST-NORTHWEST…WITH AN INITIAL
MOTION OF 290/11 KT. THE HURRICANE IS BEING STEERED BY A RIDGE ALOFT
EXTENDING WEST FROM AN ANTICYCLONE ALOFT FAR TO THE NORTHEAST.
HILDA WILL REACH THE WESTERN EDGE OF THE RIDGE BY THIS EVENING AND
WE EXPECT A TURN TOWARD THE NORTHWEST AT THAT TIME. HILDA IS
EXPECTED TO START MOVING MORE SLOWLY AS IT TURNS TOWARD THE
NORTHWEST AS THE STEERING FLOW WILL BE QUITE WEAK.

FOR CLARITY AND CONVENIENCE WE USUALLY WRITE SEPARATE PARAGRAPHS
FOR INTENSITY AND MOVEMENTS…BUT THE TRACK AND INTENSITY FORECASTS
FOR HILDA CANNOT BE CONSIDERED SEPARATELY. IF HILDA WERE TO REMAIN A
STRONG AND DEEP SYSTEM…HER TRACK WOULD LIKELY TO BE INFLUENCED BY
STEERING FLOW THROUGH A DEEPER LAYER OF THE ATMOSPHERE. THAT WOULD
MEAN A MORE NORTHERLY TRACK. THE WEAKER AND SHALLOWER HILDA
BECOMES…THE MORE ITS TRACK WILL BE INFLUENCED BY THE TRADE-WIND
FLOW IN THE LOWER PART OF THE ATMOSPHERE. THAT WOULD GIVE HILDA A
MORE WESTERLY TRACK.

THE MODELS ARE SHOWING GOOD AGREEMENT ON AN ACCELERATING WEAKENING
TREND AS HILDA ENCOUNTERS SOUTHWEST SHEAR NEAR 40 KT DUE TO A
SUBTROPICAL JET STREAM SOUTH OF A TROPICAL UPPER TROPOSPHERIC
TROUGH OR TUTT. THE MODELS ARE INCREASINGLY GOOD AGREEMENT ON HILDA
TAKING A MORE WESTERLY TRACK AS IT WEAKENS. I HAVE SHIFTED THE
TRACK A BIT FURTHER TO THE LEFT…CLOSER TO THE MODEL CONSENSUS…
WHILE CONTINUING A STEADY WEAKENING.

U.S AIR FORCE HURRICANE HUNTERS ARE SCHEDULED TO BEGIN FLYING
MISSIONS INTO HILDA THIS EVENING. THE DATA FROM THESE MISSIONS
SHOULD HELP REFINE OUR FUTURE FORECASTS.

FORECAST POSITIONS AND MAX WINDS

INIT 09/2100Z 15.0N 147.4W 95 KT 110 MPH
12H 10/0600Z 15.6N 148.7W 90 KT 105 MPH
24H 10/1800Z 16.5N 149.8W 85 KT 100 MPH
36H 11/0600Z 17.3N 150.5W 70 KT 80 MPH
48H 11/1800Z 18.0N 151.0W 55 KT 65 MPH
72H 12/1800Z 18.8N 152.0W 40 KT 45 MPH
96H 13/1800Z 19.2N 153.5W 35 KT 40 MPH
120H 14/1800Z 19.5N 155.5W 30 KT 35 MPH

$$
FORECASTER DONALDSON

 

 

WTPA25 PHFO 092038
TCMCP5

HURRICANE HILDA FORECAST/ADVISORY NUMBER 16
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP102015
2100 UTC SUN AUG 09 2015

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE MAIN HAWAIIAN ISLANDS SHOULD MONITOR THE PROGRESS
OF HILDA.

HURRICANE CENTER LOCATED NEAR 15.0N 147.4W AT 09/2100Z
POSITION ACCURATE WITHIN 15 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 9 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 964 MB
MAX SUSTAINED WINDS 95 KT WITH GUSTS TO 115 KT.
64 KT……. 20NE 20SE 10SW 20NW.
50 KT……. 30NE 30SE 20SW 30NW.
34 KT……. 80NE 60SE 40SW 60NW.
12 FT SEAS..270NE 120SE 210SW 270NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT…CENTER LOCATED NEAR 15.0N 147.4W AT 09/2100Z
AT 09/1800Z CENTER WAS LOCATED NEAR 14.8N 147.0W

FORECAST VALID 10/0600Z 15.6N 148.7W
MAX WIND 90 KT…GUSTS 110 KT.
64 KT… 20NE 20SE 10SW 20NW.
50 KT… 30NE 30SE 20SW 30NW.
34 KT… 80NE 60SE 40SW 60NW.

FORECAST VALID 10/1800Z 16.5N 149.8W
MAX WIND 85 KT…GUSTS 105 KT.
64 KT… 20NE 20SE 10SW 20NW.
50 KT… 30NE 30SE 20SW 30NW.
34 KT… 80NE 60SE 40SW 60NW.

FORECAST VALID 11/0600Z 17.3N 150.5W
MAX WIND 70 KT…GUSTS 85 KT.
64 KT… 20NE 20SE 10SW 20NW.
50 KT… 30NE 30SE 20SW 30NW.
34 KT… 80NE 60SE 40SW 60NW.

FORECAST VALID 11/1800Z 18.0N 151.0W
MAX WIND 55 KT…GUSTS 65 KT.
50 KT… 30NE 30SE 10SW 30NW.
34 KT… 85NE 55SE 30SW 65NW.

FORECAST VALID 12/1800Z 18.8N 152.0W
MAX WIND 40 KT…GUSTS 50 KT.
34 KT… 60NE 45SE 20SW 60NW.

EXTENDED OUTLOOK. NOTE…ERRORS FOR TRACK HAVE AVERAGED NEAR 125 NM
ON DAY 4 AND 150 NM ON DAY 5…AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 13/1800Z 19.2N 153.5W
MAX WIND 35 KT…GUSTS 45 KT.

OUTLOOK VALID 14/1800Z 19.5N 155.5W
MAX WIND 30 KT…GUSTS 40 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 15.0N 147.4W

NEXT ADVISORY AT 10/0300Z

$$
FORECASTER DONALDSON

FOPA15 PHFO 092039
PWSCP5

HURRICANE HILDA WIND SPEED PROBABILITIES NUMBER 16
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP102015
2100 UTC SUN AUG 09 2015

AT 2100Z THE CENTER OF HURRICANE HILDA WAS LOCATED NEAR LATITUDE
15.0 NORTH…LONGITUDE 147.4 WEST WITH MAXIMUM SUSTAINED WINDS NEAR
95 KTS…110 MPH…175 KM/H.

Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH)
PACIFIC DAYLIGHT TIME (PDT)…SUBTRACT 7 HOURS FROM Z TIME
HAWAIIAN STANDARD TIME (HST)…SUBTRACT 10 HOURS FROM Z TIME

WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS

CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST
…34 KT (39 MPH… 63 KM/H)…
…50 KT (58 MPH… 93 KM/H)…
…64 KT (74 MPH…119 KM/H)…
FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS

PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE
OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING
AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY)
(CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN
18Z SUN AND THE FORECAST HOUR (CUMULATIVE PROBABILITY)

PROBABILITIES ARE GIVEN IN PERCENT
X INDICATES PROBABILITIES LESS THAN 1 PERCENT
PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN
THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT.
PROBABILITIES FOR 64 KT ARE SHOWN WHEN THE 5-DAY CUMULATIVE
PROBABILITY IS AT LEAST 1 PERCENT.

– – – – WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS – – – –

FROM FROM FROM FROM FROM FROM FROM
TIME 18Z SUN 06Z MON 18Z MON 06Z TUE 18Z TUE 18Z WED 18Z THU
PERIODS TO TO TO TO TO TO TO
06Z MON 18Z MON 06Z TUE 18Z TUE 18Z WED 18Z THU 18Z FRI

FORECAST HOUR (12) (24) (36) (48) (72) (96) (120)
– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –
LOCATION KT

15N 150W 34 9 26(35) 3(38) 2(40) X(40) X(40) X(40)
15N 150W 50 1 7( 8) 1( 9) X( 9) X( 9) X( 9) X( 9)
15N 150W 64 X 3( 3) X( 3) X( 3) X( 3) X( 3) X( 3)

20N 150W 34 X 2( 2) 7( 9) 9(18) 6(24) 2(26) X(26)
20N 150W 50 X X( X) X( X) 2( 2) 1( 3) X( 3) X( 3)

20N 151W 34 X 2( 2) 7( 9) 11(20) 8(28) 2(30) X(30)
20N 151W 50 X X( X) 1( 1) 2( 3) 3( 6) 1( 7) X( 7)
20N 151W 64 X X( X) X( X) 1( 1) X( 1) X( 1) X( 1)

BUOY 51004 34 X 4( 4) 17(21) 10(31) 4(35) 1(36) X(36)
BUOY 51004 50 X X( X) 3( 3) 3( 6) 2( 8) X( 8) X( 8)
BUOY 51004 64 X X( X) 1( 1) X( 1) 1(2) X( 2) X( 2)

20N 154W 34 X X( X) 3( 3) 2( 5) 7(12) 3(15) X(15)

15N 155W 34 X X( X) 2( 2) 1( 3) 1( 4) 1( 5) X( 5)

HILO 34 X X( X) 2( 2) 1( 3) 3( 6) 3( 9) 1(10)

BRADSHAW AAF 34 X X( X) 1( 1) 1( 2) 2( 4) 3( 7) 1( 8)

18N 156W 34 X X( X) 1( 1) 1( 2) 1( 3) 2( 5) 1( 6)

SOUTH POINT 34 X X( X) 1( 1) 1( 2) 3( 5) 2( 7) 1( 8)

21N 156W 34 X X( X) X( X) 1( 1) 1( 2) 2( 4) 2( 6)

KAILUA-KONA 34 X X( X) 1( 1) X( 1) 2( 3) 2( 5) 1( 6)

KAHULUI 34 X X( X) X( X) X( X) 2( 2) 2( 4) 1( 5)

21N 158W 34 X X( X) X( X) X( X) X( X) 1( 1) 2( 3)

LANAI CITY 34 X X( X) X( X) X( X) 1( 1) 2( 3) 1( 4)

KAUNAKAKAI 34 X X( X) X( X) X( X) 1( 1) 1( 2) 2( 4)

$$
FORECASTER DONALDSON