Flash Flood in Hawaii, March 31, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 PM HST FRI MAR 31 2006

.SYNOPSIS...
LOCALLY HEAVY SHOWERS WITH A CHANCE OF THUNDERSTORMS WILL CONTINUE
OVER THE MAIN HAWAIIAN ISLANDS INTO THE WEEKEND WITH GRADUAL
IMPROVEMENT EXPECTED SUNDAY AND MONDAY.

&&

.DISCUSSION...
OAHU WAS THE FOCAL POINT FOR HEAVY RAIN AND THUNDERSTORMS TODAY. LOW
LEVEL CONVERGENCE COMBINED WITH AN UPPER LEVEL DISTURBANCE PASSING
OVERHEAD BROUGHT A BURST OF HEAVY RAINS AND THUNDERSTORMS TO THE
EASTERN HALF OF THE ISLAND. THREE-HOUR RAIN TOTALS FROM THE AFFECTED
AREA GENERALLY RANGED FROM 2 TO 3 INCHES...WITH THE HEAVY SHOWERS
MOVING OFF THE WINDWARD COAST AROUND 2 PM HST.

THE POTENTIAL FOR ADDITIONAL HEAVY SHOWERS AND THUNDERSTORMS WILL
CONTINUE TONIGHT...PARTICULARLY OVER THE WESTERN AND CENTRAL
PORTIONS OF THE STATE...AND WILL PERSIST THROUGH SATURDAY FOR THE
ENTIRE ISLAND CHAIN. AN UPPER LEVEL LOW PARKED ABOUT 275 MILES
NORTHWEST OF KAUAI IS RESPONSIBLE FOR THE WET AND UNSTABLE
CONDITIONS. IT WILL REMAIN NEARLY STATIONARY WEST OF KAUAI THROUGH
SATURDAY AS IT SLOWLY WEAKENS. DURING THIS TIME DISTURBANCES ALOFT
WILL CONTINUE TO ROTATE AROUND THE UPPER LOW...TRIGGERING BOUTS OF
HEAVY RAINFALL AND THUNDERSTORMS. FOR TONIGHT AND SATURDAY...THESE
DISTURBANCES WILL LIKELY AFFECT THE WESTERN AND CENTRAL PORTIONS OF
THE STATE...GIVING KAUAI...OAHU...AND MAUI COUNTY THE GREATEST
THREAT FOR HEAVY RAINFALL. AS A RESULT THE FLASH FLOOD WATCH HAS
BEEN EXTENDED THROUGH SATURDAY AFTERNOON.

FORECAST MODELS ARE CONSISTENT IN SLOWLY WEAKENING THE UPPER LOW AND
MOVING IT EASTWARD OVER THE ISLANDS SATURDAY NIGHT AND SUNDAY. THE
THREAT FOR HEAVY SHOWERS AND THUNDERSTORMS WILL DECREASE DURING THIS
TIME. THE ATMOSPHERE WILL STILL BE UNSTABLE...SO WE CANNOT RULE OUT
LOCALIZED HEAVY SHOWERS. BUT...THE TREND APPEARS TO BE POINTING
TOWARDS IMPROVING WEATHER FOR THE SECOND HALF OF THE WEEKEND WITH A
BUILDING EASTERLY FLOW. WE DROPPED THE WINTER WEATHER ADVISORY FOR
THE BIG ISLAND SUMMITS EARLIER TODAY...BUT THIS AREA WILL BE
MONITORED CLOSELY FOR ANY HEAVY SNOW POTENTIAL AS THE UPPER LOW
SWINGS THROUGH.

BY EARLY NEXT WEEK...ALL FORECAST MODELS BRING TRADE WINDS BACK TO
THE STATE...BUT WEAK TROUGHING ALOFT LINGERS...MAINTAINING SOME
INSTABILITY. THUS...THE FORECAST CALLS FOR WET TRADE WINDS AS I AM
NOT CONFIDENT ENOUGH TO CALL FOR A RETURN TO DRIER TRADE WIND
WEATHER PATTERN JUST YET.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH EXTENDED THROUGH 4 PM HST SATURDAY FOR ALL
HAWAIIAN ISLANDS.

&&

WROE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HONOLULU HI
1056 AM HST FRI MAR 31 2006

HIZ005-312300-
OAHU SOUTH SHORE-
INCLUDING THE CITIES OF...HONOLULU...WAIKIKI...HAWAII KAI...
KAPOLEI
1056 AM HST FRI MAR 31 2006

AT 1045 AM...DOPPLER RADAR SHOWED AN AREA OF SHOWERS AND EMBEDDED
THUNDERSTORMS JUST OFFSHORE OF THE OAHU LEEWARD WATERS FROM JUST
SOUTH OF EWA BEACH...EASTWARD TO JUST SOUTH OF WAIKIKI. THIS AREA
WILL MOVE ONSHORE BETWEEN 1100 AM AND 1130 AM...BRINGING MODERATE
TO HEAVY RAIN AND OCCASIONAL CLOUD TO GROUND LIGHTNING TO MUCH OF
THE HONOLULU METROPOLITAN AREA.

REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING. MOVE INDOORS UNTIL THE STORM PASSES.

BROWNING

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HONOLULU HI
155 PM HST FRI MAR 31 2006

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1230 PM     FLASH FLOOD      MAKIKI                  21.31N 157.84W
03/31/2006                   HONOLULU           HI   EMERGENCY MNGR

            MAKIKI STREAM OVERFLOWED NEAR FERN ST PRODUCING 3 TO 4 FT
            DEEP WATER NEAR MOKU PL.

0100 PM     FLASH FLOOD      MANOA                   21.32N 157.81W
03/31/2006                   HONOLULU           HI   EMERGENCY MNGR

            MANOA STREAM OVERFLOWED AT THE WOODLAWN ST. BRIDGE

&&

KODAMA