Flash Flood Warning 122, NWS Honolulu, HI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 PM HST SUN APR 2 2006

.SYNOPSIS...
THUNDERSTORMS REMAIN A POSSIBILITY THROUGHOUT THE NIGHT ACROSS THE
MAIN HAWAIIAN ISLANDS. EXPECT A RETURN TO MORE TYPICAL TRADE WIND
WEATHER STARTING MONDAY. TRADES ARE EXPECTED TO CONTINUE THROUGHOUT
THE WORK WEEK.
&&

.DISCUSSION...
AROUND 900 AM THIS MORNING...A THUNDERSTORM DEVELOPED AND MOVED
ONSHORE BETWEEN KANEOHE AND KAILUA. THE THUNDERSTORMS AND SHOWERS
EXPANDED QUICKLY TO COVER MOST OF THE WINDWARD SIDE OF OAHU...
PROMPTING THE ISSUANCE OF A FLASH FLOOD WARNING FOR THAT AREA. THE
WILSON TUNNEL RAIN GAGE REPORTED A RAINFALL RATE OF 3.12 INCHES PER
HOUR AT 1115 WITH THIS STORM. SHORTLY AFTER THE THUNDERSTORMS
DEVELOPED OVER WINDWARD OAHU...THUNDERSTORM ACTIVITY DEVELOPED OVER
THE SOUTH SHORE OF KAUAI...WITH SHOWERS OVER INTERIOR PARTS OF THE
GARDEN ISLE. THUNDERSTORMS OVER THE WINDWARD SIDE OF OAHU CONTINUED
TO FORM DURING THE EARLY AFTERNOON. THESE EVENTS...COMBINED WITH THE
RECENT RAINS ACROSS THE ISLANDS...SUPPORT THE CONTINUATION OF THE
FLASH FLOOD WATCH FOR NIIHAU...KAUAI...AND OAHU.

THE RAIN GAGE AT WILSON TUNNEL REPORTED 3.97 INCHES OF RAIN BETWEEN
8 AM THIS MORNING AND 2 PM THIS AFTERNOON. THIS WAS THE MOST RAIN
REPORTED BY ANY GAGE ON OAHU TODAY. OTHER SIGNIFICANT REPORTS FOR
THE SAME TIME PERIOD ARE 2.66 AT MAUNAWILI...AND 2.18 AT LULUKU.
OTHER WINDWARD GAGES REPORTED RAIN TOTALS LESS THAN 1.13 INCHES.

AROUND 1 PM...THUNDER WAS HEARD ON THE BIG ISLAND...AND
THUNDERSTORMS/HEAVY RAIN DEVELOPED OVER MOLOKAI SHORTLY THEREAFTER.
AN AREA OF CONVECTION WAS ABOUT 100 MILES NORTHEAST OF MAUI AT 2
PM...AND THIS AREA WAS MOVING TOWARDS THE ISLANDS AROUND 15 MILES AN
HOUR. IF THIS AREA HOLDS TOGETHER...AND IF THE MOVEMENT CONTINUES...
IT IS EXPECTED TO ARRIVE IN THE MAUI COUNTY/BIG ISLAND AREA EARLY
THIS EVENING. EARLIER IN THE DAY...THIS AREA WAS MOVING TOWARDS THE
SOUTHEAST...BUT MORE RECENTLY IT HAS BEEN MOVING TO THE SOUTH.

THE WEAK UPPER LEVEL TROUGH OVER THE ISLANDS HAS MOVED DOWN THE
ISLAND CHAIN DURING THE DAY TODAY. ACARS SOUNDINGS FROM THE LIHUE
AREA SUGGEST MORE STABLE WEATHER IS ALREADY ESTABLISHING ITSELF OVER
KAUAI THIS AFTERNOON. EQUIPMENT MALFUNCTION WILL PREVENT A SOUNDING
FROM PHLI THIS AFTERNOON. AN ACARS SOUNDING FROM THE KONA AREA SHOWS
UNSTABLE CONDITIONS SETTING UP NEAR THE BIG ISLAND. AS A RESULT OF
THESE ISSUES...AND THE WEATHER OVER MAUI COUNTY AND THE BIG
ISLAND...HAVE EXPANDED THE FLASH FLOOD WATCH TO INCLUDE ALL THE
MAIN HAWAIIAN ISLANDS...AND HAVE EXTENDED IT THROUGH 4 AM MONDAY
MORNING.

THE AREA OF CONVECTION NORTHEAST OF MAUI COUNTY IS OF SPECIAL
CONCERN THIS AFTERNOON...AND HAS PROMPTED US TO INCREASE POPS/SKY
TONIGHT...AND INCLUDE THE WORDING FOR LOCALLY HEAVY RAINFALL. THE
INSTABILITY OF THE SYSTEM HAS ALSO LED US TO PUT THUNDERSTORMS INTO
THE FORECAST THROUGH TONIGHT.

THE MODELS ARE IN GOOD AGREEMENT WITH THE DEVELOPMENT OF A SURFACE
HIGH NORTH OF THE ISLANDS OVER THE NEXT COUPLE OF DAYS. AS THIS HIGH
STRENGTHENS...WE CAN EXPECT THE TRADE WINDS TO STRENGTHEN. THE HIGH
IS EXPECTED TO BE NORTH OF THE ISLANDS THROUGH THE WEEK.

THERE IS ALSO FAIRLY GOOD AGREEMENT THAT THE WEAK UPPER LEVEL TROUGH
OVER THE ISLANDS TODAY WILL CONTINUE IT/S WEAKENING TREND OVERNIGHT.
AS IT WEAKENS...THE THREAT FOR THUNDERSTORMS AND HEAVY RAIN WILL
DIMINISH.

THE MODELS DO SUGGEST AN UPPER LEVEL TROUGH WILL ONCE AGAIN DIG DOWN
OVER THE EASTERN END OF THE STATE MID WEEK. WILL HOLD OFF FOR RIGHT
NOW ON ENHANCING THE TRADES FOR MID WEEK...BUT WILL BE MONITORING
FOR THAT POSSIBILITY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH ALL HAWAIIAN ISLANDS THROUGH 4 AM MONDAY MORNING.

&&

M BALLARD

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HONOLULU HI
139 PM HST SUN APR 02 2006

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

0115 PM     LIGHTNING        HAUULA                  21.59N 157.92W
04/02/2006                   HONOLULU           HI   EMERGENCY MNGR

            LIGHTNING HIT 2 POLES ON KAWAIPUNA STREET. ELECTRICITY IS
            OUT IN HAUULA AND THERE ARE LINES ON THE ROADWAY.

&&

HFO

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HONOLULU HI
338 PM HST SUN APR 02 2006

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

0337 PM     FLASH FLOOD      WAIKANE                 21.50N 157.88W
04/02/2006                   HONOLULU           HI   EMERGENCY MNGR

            WAIKANE STREAM OVERFLOWING.

&&

HFO