Flash Flood Warning 11, NWS Honolulu, HI

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HONOLULU HI
758 AM HST TUE MAR 6 2012

.UPDATE...
MID-LEVEL MOISTURE MOVING OVER THE BIG ISLAND SUMMITS WILL BRING
SNOW SHOWERS TO THE SUMMITS TODAY. ISSUED A WINTER WEATHER
ADVISORY TO ACCOUNT FOR THIS AND UPDATED THE FORECAST.

&&

.SYNOPSIS...
A TROUGH ALOFT PASSING NORTHWEST OF THE STATE WILL CONTINUE TO
PRODUCE UNSETTLED WEATHER ACROSS THE WESTERN PORTION OF THE STATE. A
NEARLY STATIONARY SURFACE TROUGH WILL BE LOCATED ACROSS THE KAUAI
CHANNEL TODAY AND TONIGHT...WITH BREEZY NORTH TO NORTHEAST WINDS
BLOWING OVER KAUAI...AND LIGHTER SOUTHERLY WINDS EXPECTED OVER THE
OTHER ISLANDS. AS THE TROUGH MOVES OFF TO THE NORTHEAST WEDNESDAY
AND THURSDAY...TRADES WILL FILL IN ACROSS THE REST OF THE STATE AND
BECOME QUITE GUSTY INTO THE WEEKEND.

&&

.DISCUSSION...

A VIGOROUS UPPER LEVEL TROUGH IS LOCATED NORTHWEST OF THE ISLANDS
AND IS BEGINNING TO LIFT TOWARDS THE EAST AND NORTHEAST. A TROUGH
AT THE SURFACE STRETCHES ACROSS THE KAUAI CHANNEL AND IS NEARLY
STATIONARY. THE SURFACE TROUGH APPEARS TO BE WEAKENING IN THE KAUAI
CHANNEL WITH NORTHERLY WINDS HAVING DECREASED ON KAUAI AND SHOWER
ACTIVITY DECREASING ALONG THE TROUGH. WATER VAPOR SHOWS DRY AIR
WRAPPING AROUND THE UPPER TROUGH ALSO HELPING TO DECREASE THE DEEP
CONVECTION OVER THE WESTERN PORTION OF THE STATE. THE GFS MODEL HAS
HANDLED THE EVOLUTION OF THESE FEATURES VERY WELL...AND HAVE LEANED
THE FORECAST TOWARDS THE 00Z AND 06Z VERSIONS. THESE SHOW ANOTHER
SHOT OF CONVECTION IS POSSIBLE LATER TODAY AS SHORTWAVES ROTATING
AROUND THE BOTTOM OF THE TROUGH HELP CREATE LIFT THROUGH THE LAYER.
THE AIRMASS WILL REMAIN UNSTABLE...AND ANY DAYTIME HEATING WILL
HELP FUEL SURFACE CONVERGENCE. SHOWERS WILL BE LIKELY WITH LOCAL
HEAVY RAIN AND ISOLATED THUNDERSTORMS THROUGH THIS AFTERNOON.

AFTER THE TROUGH LIFTS NORTHEAST OF THE STATE TONIGHT AND
WEDNESDAY...TRADES WILL FILL BACK IN ACROSS THE STATE. ENOUGH
INSTABILITY WILL REMAIN FOR ENHANCED TRADE SHOWERS WEDNESDAY THROUGH
FRIDAY...ESPECIALLY FOCUSING ALONG THE TRAILING REMNANTS OF THE
TROUGH/FRONTAL BOUNDARY AS IT SLIDES SOUTH TO THE BIG ISLAND BY
FRIDAY. A STABILIZING TREND IS EXPECTED FOR THE END OF THE
WEEK...THUS THE TRADE SHOWERS WILL REDUCE IN COVERAGE AND INTENSITY.
THE WEEKEND PATTERN STILL FEATURES BREEZY TRADES ACROSS THE ISLANDS
AS A RIDGE REMAINS FAR TO THE NORTH. A STABLE AIRMASS ACROSS THE
STATE WILL KEEP SHOWERS TO A MINIMUM. EARLY NEXT WEEK...MODELS HAVE
INDICATED A WEAK FRONTAL OR SHEARLINE MOVING ACROSS THE ISLANDS FROM
THE NORTHEAST AROUND MONDAY...AND THIS MAY PROVIDE ANOTHER INCREASE
IN TRADE SHOWERS.

&&

.HYDROLOGY...
SATURATED SOILS WITH BOUTS OF HEAVY RAIN WILL RESULT IN CONTINUED
THREAT FOR FLASH FLOODING FROM MAUI WESTWARD TO KAUAI. THE FLASH
FLOOD THREAT WILL REMAIN HIGH THROUGH AT LEAST LATE THIS AFTERNOON
AS HEAVY SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP IN THE
UNSTABLE AIRMASS. A FLASH FLOOD WATCH IS IN EFFECT THROUGH 600 PM
HST TODAY FOR KAUAI...HONOLULU AND MAUI COUNTIES. PLEASE SEE OUR
WEBSITE AT WWW.WEATHER.GOV/HAWAII FOR THE LATEST AND SPECIFIC FLASH
FLOOD WARNING OR ADVISORY INFORMATION FOR YOUR AREA.

&&

.AVIATION...
WIDESPREAD CONVECTION CONTINUES ACROSS THE FA THIS MORNING...MAINLY
FOCUSED ON THE CENTRAL ISLANDS. EXPECT TEMPO TSRA +RA WITH
OCCASIONAL MVFR/IFR CONDITIONS AT HONOLULU/MAUI COUNTY TERMINALS.
AIRMET SIERRA REMAINS IN EFFECT FOR ALL ISLANDS. LLVL TURB IS
EXPECTED OVER THE FAR WRN PORTION OF THE STATE WHERE STRONGER NE FLOW
IS IN GEAR. MID-HIGH LEVEL LYRD CONVECTIVE DEBRIS COULD PRODUCE
FROZEN PRECIP OVER THE BIG ISLAND SUMMITS.

SIGMET OSCAR REMAINS IN EFFECT FOR TSRA OVER THE ISLAND TOPS TO
FL480-FL500...AND WILL CONTINUE MOST OF THE DAY WHILE SHIFTING
GRADUALLY EAST.

&&

.MARINE...
THE LARGE NORTH NORTHEAST SWELL CONTINUES TO POUND THE EAST FACING
SHORES WITH WARNING LEVEL SURF HEIGHTS. IN ADDITION...THE NORTH
FACING SHORES ARE HAVING ADVISORY LEVEL SURF FROM THIS SWELL. THE
SWELL WILL REMAIN AT THESE LEVELS THROUGH WEDNESDAY...THEN
GRADUALLY DECREASE.

ROUGH COMBINED SEAS WILL RESULT IN HAZARDOUS CONDITIONS FOR SMALL
CRAFT THROUGHOUT MOST HAWAIIAN COASTAL WATERS...AND A SMALL CRAFT
ADVISORY IS IN EFFECT THROUGH EARLY WEDNESDAY MORNING.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 6 PM HST THIS EVENING FOR NIIHAU-KAUAI-
OAHU-MOLOKAI-LANAI-KAHOOLAWE-MAUI.

HIGH SURF ADVISORY UNTIL 6 PM HST WEDNESDAY FOR NIIHAU-OAHU
NORTH SHORE-MOLOKAI-MAUI CENTRAL VALLEY.

HIGH SURF WARNING UNTIL 6 PM HST WEDNESDAY FOR KAUAI WINDWARD-
OAHU KOOLAU-OLOMANA-MAUI WINDWARD WEST-WINDWARD HALEAKALA-BIG
ISLAND NORTH AND EAST.

WINTER WEATHER ADVISORY UNTIL 6 PM HST THIS EVENING FOR BIG
ISLAND SUMMITS.

WIND ADVISORY UNTIL 6 AM HST WEDNESDAY FOR BIG ISLAND SUMMITS.

SMALL CRAFT ADVISORY UNTIL 6 AM HST WEDNESDAY FOR ALL HAWAIIAN
WATERS EXCEPT MAALAEA BAY-

&&

MORRISON

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HONOLULU HI
712 AM HST TUE MAR 6 2012

HIZ013-061815-
MOLOKAI LEEWARD-
712 AM HST TUE MAR 6 2012

A STRONG THUNDERSTORM PRODUCING GUSTY WINDS UP TO 50 MPH AND
DANGEROUS CLOUD TO GROUND LIGHTNING WILL MOVING FROM SOUTHWEST TO
NORTHEAST ALONG THE WESTERN COAST OF MOLOKAI BETWEEN 715 AND 800
AM. THIS THUNDERSTORM WILL AFFECT PAPOHAKU BEACH AND ILIO POINT.

WROE