WTPA35 PHFO 120558
TCPCP5

BULLETIN
TROPICAL STORM HILDA INTERMEDIATE ADVISORY NUMBER 25A
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP102015
800 PM HST TUE AUG 11 2015

…TROPICAL STORM HILDA WEAKENING AND SLOWING…
…TROPICAL STORM WATCH REMAINS IN EFFECT FOR HAWAII COUNTY…

SUMMARY OF 800 PM HST…0600 UTC…INFORMATION
———————————————-
LOCATION…17.0N 151.9W
ABOUT 280 MI…450 KM SE OF HILO HAWAII
ABOUT 490 MI…790 KM SE OF HONOLULU HAWAII
MAXIMUM SUSTAINED WINDS…65 MPH…100 KM/H
PRESENT MOVEMENT…W OR 270 DEGREES AT 1 MPH…2 KM/H
MINIMUM CENTRAL PRESSURE…1000 MB…29.53 INCHES

WATCHES AND WARNINGS
——————–
CHANGES IN WATCHES AND WARNINGS 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 HAWAIIAN ISLANDS SHOULD CONTINUE TO
MONITOR THE PROGRESS OF HILDA.

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 800 PM HST…0600 UTC…THE CENTER OF TROPICAL STORM HILDA WAS
LOCATED NEAR LATITUDE 17.0 NORTH…LONGITUDE 151.9 WEST. HILDA IS
MOVING TOWARD THE WEST NEAR 1 MPH…2 KM/H. THE CENTER OF HILDA
RECENTLY TOOK A WOBBLE TO THE EAST…AND A SLOW WESTWARD MOTION IS
EXPECTED TO RESUME TONIGHT AND CONTINUE DURING THE NEXT TWO DAYS.

MAXIMUM SUSTAINED WINDS ARE NEAR 65 MPH…100 KM/H…WITH HIGHER
GUSTS. STEADY WEAKENING IS EXPECTED OVER THE NEXT COUPLE OF
DAYS…AND HILDA IS EXPECTED TO BECOME A TROPICAL DEPRESSION
WEDNESDAY NIGHT OR THURSDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 85 MILES…140 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB…29.53 INCHES.

HAZARDS AFFECTING LAND
———————-
SURF…SWELLS ASSOCIATED WITH TROPICAL STORM HILDA WILL PRODUCE
LARGE AND POTENTIALLY LIFE THREATENING SURF ALONG EAST AND SOUTHEAST
FACING SHORES OF PORTIONS OF THE HAWAIIAN ISLANDS OVER THE NEXT
DAY OR TWO.

RAINFALL…HILDA MAY PRODUCE 6 TO 12 INCHES OF RAINFALL…WITH
MAXIMUM VALUES OF UP TO 18 INCHES POSSIBLE…ALONG AND NORTH OF ITS
PATH. THESE RAINS COULD RESULT IN LIFE THREATENING FLASH FLOODS AND
MUD SLIDES ACROSS PORTIONS OF THE HAWAIIAN ISLANDS LATE WEDNESDAY
INTO THE WEEKEND.

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

$$
FORECASTER WROE



WTPA45 PHFO 120245
TCDCP5

TROPICAL STORM HILDA DISCUSSION NUMBER 25
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP102015
500 PM HST TUE AUG 11 2015

SATELLITE IMAGERY INDICATES THAT THE LOW LEVEL CIRCULATION CENTER
OF HILDA IS COMPLETELY EXPOSED FROM THE DEEP CONVECTION…WHICH IS
NOW WELL DISPLACED TO THE EAST OF THE SYSTEM. THE WESTERLY VERTICAL
WIND SHEAR HAS WON THE BATTLE…AND IS CURRENTLY ESTIMATED TO BE 38
KNOTS AT 260 DEGREES BY UW-CIMSS SHEAR ANALYSIS. GIVEN THE POOR
SATELLITE PRESENTATION OF HILDA…IT COMES AS NO SURPRISE THAT THE
LATEST SATELLITE FIXES FROM SAB…PHFO AND JTWC HAVE WEAKENED THE
SYSTEM AS WELL. THE LATEST DATA T NUMBERS WERE 3.5/55 KNOTS AT ALL
THREE AGENCIES…SO THIS WAS USED AS THE INITIAL INTENSITY WITH THE
03Z ADVISORY. TRACKING THE LOW LEVEL CIRCULATION CENTER VIA VISIBLE
SATELLITE IMAGERY…THE INITIAL MOTION VECTOR WAS SET AT 270
DEGREES AT 4 KNOTS.

THE TRACK OF HILDA WAS SHIFTED SOUTH OF THE PREVIOUS OFFICIAL TRACK
WITH THIS ADVISORY…AND REMAINS TO THE SOUTH OF THE CONSENSUS
GUIDANCE. THE MODELS CONTINUE TO STRUGGLE WITH THE INITIAL MOTION
OF THE SYSTEM OFF TO THE WEST…LIKELY ATTRIBUTED TO THE
INITIALIZATION WHICH IS BASED ON A NORTHWESTWARD MOVEMENT OF THE
SYSTEM OVER THE PAST 18 TO 24 HOURS. AS A RESULT…THE OFFICIAL
FORECAST DISREGARDED THE INITIAL NORTHWEST MOTION SEEN IN THE
MAJORITY OF THE MODELS…AND TAKES THE SYSTEM SLOWLY WESTWARD AT A
SPEED CLOSE TO THE GUIDANCE CONSENSUS.

PERSISTENT STRONG WESTERLY VERTICAL WIND SHEAR REMAINING IN PLACE
OVER HILDA…ALONG WITH THE ENTRAINMENT OF VERY DRY MID/UPPER
LEVEL AIR AS EVIDENT IN WATER VAPOR IMAGERY…SHOULD CONTINUE TO
STEADILY WEAKEN THE SYSTEM OVER THE NEXT COUPLE OF DAYS. THE
INTENSITY FORECAST IS CLOSELY ALIGNED WITH ICON…AND CALLS FOR
HILDA TO WEAKEN INTO A TROPICAL DEPRESSION WEDNESDAY NIGHT OR
THURSDAY…AND BECOME A REMNANT LOW BY FRIDAY AFTERNOON.

THE U.S. AIR FORCE HURRICANE HUNTERS HAVE DEPARTED ON THERE WAY TO
FLY ANOTHER MISSION INTO HILDA THIS EVENING. THE VALUABLE DATA FROM
THIS MISSION SHOULD HELP REFINE OUR FUTURE TRACK AND INTENSITY
FORECASTS.

FORECAST POSITIONS AND MAX WINDS

INIT 12/0300Z 17.0N 152.2W 55 KT 65 MPH
12H 12/1200Z 17.1N 152.7W 45 KT 50 MPH
24H 13/0000Z 17.2N 153.4W 40 KT 45 MPH
36H 13/1200Z 17.2N 154.3W 35 KT 40 MPH
48H 14/0000Z 17.2N 155.4W 30 KT 35 MPH
72H 15/0000Z 17.0N 158.5W 25 KT 30 MPH…POST-TROP/REMNT LOW
96H 16/0000Z…DISSIPATED

$$
FORECASTER JELSEMA/POWELL