WTPA35 PHFO 120843
TCPCP5

BULLETIN
TROPICAL STORM HILDA ADVISORY NUMBER 26
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP102015
1100 PM HST TUE AUG 11 2015

…TROPICAL STORM HILDA CONTINUES TO WEAKEN AS THE FORWARD MOTION
SLOWS…
…TROPICAL STORM WATCH REMAINS IN EFFECT FOR HAWAII COUNTY…

SUMMARY OF 1100 PM HST…0900 UTC…INFORMATION
———————————————–
LOCATION…17.2N 151.7W
ABOUT 280 MI…455 KM SE OF HILO HAWAII
ABOUT 495 MI…795 KM SE OF HONOLULU HAWAII
MAXIMUM SUSTAINED WINDS…60 MPH…95 KM/H
PRESENT MOVEMENT…WNW OR 290 DEGREES AT 2 MPH…4 KM/H
MINIMUM CENTRAL PRESSURE…996 MB…29.42 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 DURING THE NEXT 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 1100 PM HST…0900 UTC…THE CENTER OF TROPICAL STORM HILDA WAS
LOCATED NEAR LATITUDE 17.2 NORTH…LONGITUDE 151.7 WEST. HILDA IS
MOVING TOWARD THE WEST-NORTHWEST NEAR 2 MPH…4 KM/H. THIS SLOW
MOTION IS EXPECTED TO CONTINUE TONIGHT WITH A GRADUAL INCREASE IN
FORWARD MOTION AND TURN TO THE WEST DURING THE NEXT COUPLE OF DAYS.

MAXIMUM SUSTAINED WINDS ARE NEAR 60 MPH…95 KM/H…WITH HIGHER
GUSTS. STEADY WEAKENING IS EXPECTED DURING THE NEXT COUPLE OF
DAYS…WITH HILDA EXPECTED TO BE A TROPICAL DEPRESSION BY THURSDAY.

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

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 996 MB…29.42 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 SATURDAY.

NEXT ADVISORY
————-
NEXT INTERMEDIATE ADVISORY…200 AM HST.
NEXT COMPLETE ADVISORY…500 AM HST.

$$
FORECASTER WROE



WTPA45 PHFO 120849
TCDCP5

TROPICAL STORM HILDA DISCUSSION NUMBER 26
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP102015
1100 PM HST TUE AUG 11 2015

DEEP CONVECTION HAS BEEN PULSING WITHIN THE EASTERN SEMICIRCLE OF
HILDA…WITH THE LOW LEVEL CIRCULATION BRIEFLY EXPOSED EARLIER
TODAY UNDER THE INFLUENCE OF STRONG VERTICAL WIND SHEAR. US AIR
FORCE RECONNAISSANCE AIRCRAFT FOUND THE LOW LEVEL CENTER WOBBLED
EASTWARD AS DEEP CONVECTION REDEVELOPED IN THE PAST SEVERAL
HOURS…AND MAXIMUM WINDS IN THE NORTHEAST QUADRANT CAME IN AT 50
KT…WHILE WIND RADII WERE FOUND TO BE SMALLER THAN EARLIER
FORECASTS. THUS…THE INITIAL INTENSITY WAS LOWERED TO 50 KT…AND
THE WIND RADII WERE DECREASED.

HILDA PERFORMED A LOOPING WOBBLE THIS EVENING…CAUSING THE CENTER
TO BRIEFLY SHIFT EASTWARD. A SLOW WEST-NORTHWEST MOTION SHOULD BE
UNDERWAY WITH THE INITIAL MOTION SET AT 290/2 KT. HILDA IS IN A
REGION OF WEAK STEERING CURRENTS. A MID TO UPPER LEVEL TROUGH OVER
THE REGION IS PRODUCING WESTERLY WINDS ALOFT…WHILE A RATHER
STRONG SURFACE HIGH FAR TO THE NORTH IS PRODUCING A SHALLOW LAYER
OF EASTERLY WINDS. AS A RESULT…HILDA IS EXPECTED TO MOVE TOWARD
THE WEST-NORTHWEST SLOWLY OVER THE NEXT DAY OR SO THEN TURN TOWARD
THE WEST AND ACCELERATE AS THE SYSTEM BECOMES INCREASINGLY SHALLOW
AND STEERED BY THE LOW LEVEL TRADE WIND FLOW. THE TRACK FORECAST
WAS SHIFTED NORTHWARD SLIGHTLY AND RUNS NEAR THE MIDDLE OF THE
GUIDANCE ENVELOPE.

STEADY WEAKENING IS EXPECTED. ACCORDING TO CIMSS…VERTICAL WIND
SHEAR IS AROUND 37 KT FROM THE WEST. THE UPPER LEVEL TROUGH
PRODUCING THIS WIND SHEAR WILL REMAIN IN PLACE DURING THE NEXT FEW
DAYS…AND HILDA WILL CONTINUE TO WEAKEN. THE FORECAST CLOSELY
FOLLOWS THE ICON AND IS NOT AS AGGRESSIVE AS THE SHIPS GUIDANCE.
HILDA IS EXPECTED TO WEAKEN TO A TROPICAL DEPRESSION ON THURSDAY AND
BECOME A REMNANT LOW BY THURSDAY NIGHT OR FRIDAY.

DUE TO UNCERTAINTY IN THE SHORT TERM TRACK…THE TROPICAL STORM
WATCH WILL REMAIN POSTED FOR THE BIG ISLAND OF HAWAII.

FORECAST POSITIONS AND MAX WINDS

INIT 12/0900Z 17.2N 151.7W 50 KT 60 MPH
12H 12/1800Z 17.3N 152.0W 45 KT 50 MPH
24H 13/0600Z 17.4N 152.6W 35 KT 40 MPH
36H 13/1800Z 17.5N 153.5W 30 KT 35 MPH
48H 14/0600Z 17.4N 154.9W 25 KT 30 MPH…POST-TROP/REMNT LOW
72H 15/0600Z 17.0N 158.5W 25 KT 30 MPH…POST-TROP/REMNT LOW
96H 16/0600Z…DISSIPATED

$$
FORECASTER WROE