Flash Flood Warning 8, NWS Honolulu, HI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST THU DEC 9 2010

.SYNOPSIS...
SOUTH WINDS WILL INCREASE IN ADVANCE OF A COLD FRONT APPROACHING
FROM THE NORTHWEST. HEAVY SHOWERS AND THUNDERSTORMS NOW OVER AND IN
VICINITY OF KAUAI WILL SPREAD OVER TO OAHU LATER TONIGHT AND TO THE
REST OF THE STATE FRIDAY AND FRIDAY NIGHT. LOCALLY HEAVY RAINFALL IS
POSSIBLE...WHICH COULD RESULT IN FLASH FLOODING.

&&

.DISCUSSION...
KAUAI AND ITS SURROUNDING WATERS GOT A BOUT OF SEVERE THUNDERSTORMS
THIS EVENING MAINLY DEALING WITH DAMAGING WINDS. THE SITUATION HAS
VERY RECENTLY EASED OVER LAND ON KAUAI BUT THE POTENTIAL REMAINS FOR
MORE SEVERE WEATHER. THUNDERSTORMS CARRYING SOME FORM OF SEVERITY
MAY EASE ON EASTWARD TO OAHU LATER TONIGHT. THIS IS THE REASON FOR
THE SEVERE THUNDERSTORM WATCH UNTIL 2 AM HST FOR OAHU. THERE IS THE
LIKELIHOOD THIS WATCH WILL BE EXTENDED NOT ONLY FOR OAHU BUT MAY BE
FOR MAUI COUNTY LATER ON. WE WILL SEE HOW THE STORMS PROGRESSES IN
THE COMING HOURS.

A WIND ADVISORY HAS BEEN ISSUED AS WELL FOR MOST OF OAHU UNTIL 6 AM
HST FRIDAY...AS WE ANTICIPATE STRENGTHENING SOUTHERLY WINDS.

THE CULPRIT OF THIS UNSETTLE WEATHER IS DUE TO A SURFACE LOW
PRESSURE SYSTEM LOCATED ABOUT 580 MILES NORTH OF OAHU. THE LOW HAS
A COLD FRONT ABOUT 250 MILES NORTHWEST OF KAUAI. WARM...MOIST AIR
LIES AHEAD OF THIS FRONT...AND COUPLED WITH GOOD DYNAMICS ALOFT...
WE ARE EXPERIENCING A BOUT OF UNSETTLED...AND SOME INSTANCES...OF
SEVERE WEATHER.

THE LOW IS FORECAST TO MOVE NORTHEASTWARD THROUGH THE NEXT 24
HOURS. THE COLD FRONT IS EXPECTED TO REACH KAUAI FRIDAY AFTERNOON...
OAHU EARLY SATURDAY MORNING...MAUI COUNTY SATURDAY AFTERNOON. BY
THE TIME THE FRONT REACHES OAHU...THE DYNAMICS WILL BE WELL NORTH OF
THE ISLANDS. SUBSEQUENTLY...THE GFS SOLUTION IS CALLING FOR
IMPROVING WEATHER AS EARLY AS SATURDAY NIGHT.

IN THE MEAN TIME...A FLASH FLOOD WATCH REMAINS IN EFFECT FOR ALL THE
MAIN HAWAIIAN ISLANDS THROUGH AT LEAST TONIGHT.

ALSO...THE WIND SENSOR ATOP HALEAKALA SUMMIT ON MAUI IS CURRENTLY
BLOWING SUSTAINED NEAR 30 MPH WITH STRONGER GUSTS TO 45 MPH. THIS
HAS WARRANTED A WIND ADVISORY FOR THE SUMMIT GOOD UNTIL 6 PM HST
FRIDAY.

FOR THE SUMMITS OF THE BIG ISLAND...WE CONTINUE TO MONITOR THE WINDS
THERE. A WINTER STORM WATCH HAS BEEN ISSUE FOR POTENTIALLY HEAVY
SNOW...EFFECTIVE AT 6 PM HST FRIDAY THROUGH FRIDAY NIGHT. THIS
TIMING WILL BE UPDATED SOONER IF CONDITIONS WARRANT.

WITH THE FRONT AND THE TROUGH ALOFT EAST OF THE BIG ISLAND SUNDAY...
A SURFACE HIGH PRESSURE WILL MOVE NORTH OF THE STATE AND TRADE WINDS
WILL RETURN. ALSO...A RIDGE ALOFT TRAILING THE TROUGH WILL MOVE OVER
THE ISLANDS FROM THE WEST RESULTING IN A MORE STABLE ATMOSPHERE.

&&

.MARINE...
THE CURRENT NORTH SWELL CONTINUES TO WANE. WE ANTICIPATE THE HIGH
SURF ADVISORY FOR NORTH AND EAST FACING SHORES TO BE DROPPED EARLY
FRIDAY MORNING.

ALSO...THE CONDITION FOR HARBOR SURGE IN THE KAHULUI AND HILO
HARBORS DUE TO THIS NORTH SWELL SHOULD EASE AS WELL.

A SMALL CRAFT ADVISORY /SCA/ CONTINUES FOR ALL OF THE COASTAL
WATERS...EXCEPT MAALAEA BAY AND THE BIG ISLAND LEEWARD WATERS DUE TO
THE LARGE NORTH SWELL. SEAS WILL DECREASE BELOW SCA CRITERIA TONIGHT
FOR MOST COASTAL WATERS. HOWEVER...INCREASING SOUTH TO SOUTHWEST
WINDS...AS WELL AS LARGER SEAS DUE TO LOCALLY GENERATED WIND
WAVES...WILL REQUIRE THE SCA TO REMAIN IN EFFECT THROUGH FRIDAY
MORNING FOR THE COASTAL WATERS AROUND KAUAI AND OAHU.

&&

.AVIATION...
TS WILL AFFECT THE HAWAIIAN ISLANDS AREA PRIMARILY WEST OF MOLOKAI
TONIGHT...LIKELY SPREADING TO MAUI COUNTY FRIDAY. THERE IS A SIGMET
FOR TS COVERING KAUAI AND OAHU. AN UPDATED AIRMET TANGO IS DUE OUT
SHORTLY FOR THE STRONG AND GUSTY LOW LEVEL WINDS FOR THE SMALLER
ISLANDS BELOW 12000 FEET.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 600 AM HST SATURDAY FOR OAHU KAUAI AND
NIIHAU.

FLASH FLOOD WATCH UNTIL 600 AM HST SATURDAY FOR MOLOKAI...MAUI...
LANAI...KAHOOLAWE AND THE BIG ISLAND.

WINTER STORM WATCH IN EFFECT FROM 6 PM HST FRIDAY EVENING TO 12 PM
HST SATURDAY AFTERNOON FOR THE SUMMIT AREAS OF MAUNA LOA AND MAUNA
KEA.

HIGH SURF ADVISORY UNTIL 600 AM HST FRIDAY MORNING FOR NORTH AND
EAST FACING SHORES OF NIIHAU...KAUAI...OAHU...MOLOKAI...MAUI AND THE
BIG ISLAND.

SMALL CRAFT ADVISORY UNTIL 600 AM HST FRIDAY FOR WATERS OF NORTHWEST
KAUAI...KAIWI CHANNEL AND PAILOLO CHANNEL.

&&

LAU

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HONOLULU HI
711 PM HST THU DEC 09 2010

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

0635 PM     TSTM WND DMG     4 W KAPAA               22.10N 159.42W
12/09/2010                   KAUAI IN KAUAI     HI   PUBLIC

            LARGE TREE DOWN...FELL ON BOAT AND ALSO DAMAGED SHED.

&&

R BALLARD