Flash Flood in Hawaii, December 4, 2005

HAWAIIAN ISLANDS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST SUN DEC 4 2005

.SYNOPSIS...
A FRONT WILL APPROACH THE ISLANDS TONIGHT AND STALL NEAR OAHU ON
MONDAY BRINGING WITH IT SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS. A TROUGH ALOFT WILL PRODUCE UNSETTLED WEATHER WITH A
CHANCE OF HEAVY SHOWERS AND POSSIBLE THUNDERSTORMS THROUGH TUESDAY
NIGHT. TRADE WIND WEATHER WILL RETURN BY WEDNESDAY AND CONTINUE
THROUGH THE END OF THE WEEK WITH CLOUDS AND SHOWERS FAVORING
WINDWARD AND MAUKA AREAS.

&&

.DISCUSSION...
A COLD FRONT ABOUT 80 MILES NORTHWEST OF KAUAI IS MOVING TOWARD THE
EAST SOUTHEAST AT AROUND 20 MPH. A PREFRONTAL CONVERGENCE BAND
CONTAINING A FEW HEAVY SHOWERS AND ISOLATED THUNDERSTORMS HAD MOVED
OVER OAHU BUT IS NOW DISSIPATING.. ANOTHER AREA OF LOCALLY HEAVY
SHOWERS IS SEEN OVER PORTIONS OF MOLOKAI AND LANAI. WINDS OVER THE
ISLANDS WILL BE LIGHT AGAIN TODAY ALLOWING AFTERNOON CLOUDS AND
SHOWERS TO FORM.

THE COLD FRONT WILL REACH KAUAI TONIGHT AND STALL NEAR OAHU TOMORROW
BRINGING CLOUDS AND SHOWERS. TRADE WINDS WILL RETURN MONDAY BUT THE
TRADES WILL INITIALLY BE RATHER LIGHT BECAUSE THE SURFACE HIGH
BEHIND THE FRONT WILL BE FAIRLY WEAK...WITH A CENTRAL PRESSURE
NEAR 1020 MB MONDAY MORNING. THE TRADES WILL GRADUALLY INCREASE TO
10 TO 20 MPH BY TUESDAY AFTERNOON WITH A 1025 MB HIGH NORTHEAST OF
THE ISLANDS.

A TROUGH ALOFT SUPPORTING THE FRONT WILL SPLIT ON MONDAY. PART OF
THE TROUGH WILL MOVE RAPIDLY AWAY TO THE EAST NORTHEAST BUT SOME
ENERGY WILL DIG SOUTH OVER THE ISLANDS. THE MODELS ARE IN PRETTY
GOOD AGREEMENT SHOWING A SHARP TROUGH ALOFT FORMING OVER THE ISLANDS
MONDAY NIGHT. COLD TEMPERATURES ALOFT ASSOCIATED WITH THE TROUGH
WILL MAKE THE ATMOSPHERE UNSTABLE. WITH LOW LEVEL MOISTURE FROM THE
DISSIPATING FRONTAL BAND LINGERING OVER THE ISLANDS...HEAVY SHOWERS
OR THUNDERSTORMS WILL BE POSSIBLE THROUGH TUESDAY NIGHT.

THE TROUGH ALOFT WILL MOVE EAST OF THE ISLANDS BY WEDNESDAY MORNING
AND THE ATMOSPHERE WILL THEN STABILIZE. A SURFACE RIDGE NORTH OF
THE ISLANDS WILL MAINTAIN TRADE WINDS THROUGH THE REST OF NEXT WEEK
WITH CLOUDS AND SHOWERS FAVORING WINDWARD AND MAUKA AREAS.

&&

.MARINE...
WEST NORTHWEST AND NORTH NORTHEAST SWELLS WILL GRADUALLY DECREASE
THROUGH THIS AFTERNOON. A STORM NORTHWEST OF THE ISLANDS IS
PRODUCING A LARGE SWELL THAT WILL ARRIVE THIS EVENING. THIS SWELL
WILL PRODUCE SURF ABOVE THE 15 FOOT ADVISORY LEVEL FOR NORTH-FACING
SHORES...AND THE 12 FOOT ADVISORY LEVEL FOR THE WEST-FACING SHORES.
WITH OPEN OCEAN SWELLS OVER 10 FEET...A SMALL CRAFT ADVISORY WILL
ALSO BE NEEDED FOR THE COASTAL WATERS EXPOSED TO THIS SWELL. SURF
WILL PEAK MONDAY AND DROP BELOW THE ADVISORY LEVEL BY TUESDAY
MORNING. A LARGER NORTHWEST SWELL NEXT THURSDAY MAY APPROACH WARNING
LEVELS.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
.HIGH SURF ADVISORY FOR NORTHWEST SWELL.

&&

BURKE