Flash Flood Warning 71, NWS Honolulu, HI

000
WGHW70 PHFO 260221
FFSHFO
HIC003-260355-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE HONOLULU HI
4 PM HST THU NOV 25 2004

...A FLASH FLOOD WARNING FOR THE ISLAND OF OAHU IN HONOLULU COUNTY 
   IS CANCELED...

DOPPLER RADAR SHOWS THAT THE STORM WHICH PRODUCED HEAVY RAIN 
OVER CENTRAL OAHU HAS DISSIPATED. OAHU CIVIL DEFENSE REPORTS NO 
FLOODING IN THE AREA. THE FLASH FLOOD WARNING IS CANCELED.

STAY TUNED TO NOAA WEATHER RADIO FOR FURTHER NATIONAL WEATHER 
SERVICE INFORMATION.

$$
HUI/DONALDSON

HAWAIIAN ISLANDS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST THU NOV 25 2004

.SYNOPSIS...
A LOW ALOFT NEAR THE BIG ISLAND OF HAWAII WILL WEAKEN AND MOVE EAST.
A SURFACE TROUGH OVER THE ISLANDS WILL WEAKEN AND MOVE WEST. THE LOW
IS MAKING THE ATMOSPHERE UNSTABLE...ESPECIALLY NEAR THE BIG ISLAND.
THE TROUGH IS KEEPING OUR WINDS LIGHT... ESPECIALLY WEST OF MAUI. AS
THE LOW MOVES FARTHER EAST...THE ATMOSPHERE WILL BECOME MORE STABLE
AND THE CHANCE OF HEAVY SHOWERS WILL DECREASE. AS THE TROUGH WEAKENS
AND MOVES WEST...LIGHT TRADE WINDS WILL SPREAD BACK OVER THE ISLANDS.

&&

.DISCUSSION...
SATELLITE IMAGERY SHOWS A LOW ALOFT CENTERED 60 MILES EAST NORTHEAST
OF HILO. THE LOW HAS BEEN MAKING THE ATMOSPHERE OVER THE ISLANDS
UNSTABLE. AT 2 AM THIS MORNING...THE LIFTED INDEX AT LIHUE WAS -5.1
AND AT HILO WAS -6.6. THERE WERE LOCALLY HEAVY SHOWERS OVER ALL THE
ISLANDS LAST NIGHT. THE SHOWERS HAVE WEAKENED SINCE SUNRISE...BUT
ISOLATED HEAVY SHOWERS REMAIN OVER NORTHEAST KAUAI...EAST MAUI AND
JUST OFF THE SOUTHEAST COAST OF THE BIG ISLAND. TRADE WINDS HAVE
SPREAD BACK OVER THE ISLANDS FROM THE BIG ISLAND TO WINDWARD
OAHU...BUT A SURFACE TROUGH IS KEEPING WINDS LIGHT AND VARIABLE OVER
KAUAI.

WATER VAPOR IMAGERY SHOWS A SHARP TROUGH ALOFT ABOUT 450 MILES WEST
NORTHWEST OF KAUAI. THIS TROUGH HAS BEEN MOVING TOWARDS THE EAST
SOUTHEAST AT 35 MPH AND DEEPENING. THE COMPUTER MODELS ARE IN GOOD
AGREEMENT IN SHOWING THE LOW NEAR HILO WEAKENING AND MOVING OFF TO
THE EAST AHEAD OF THE APPROACHING TROUGH. THE ATMOSPHERE OVER THE
ISLANDS WILL STABILIZE AS THE LOW MOVES AWAY BUT IT MAY STILL BE
UNSTABLE ENOUGH NEAR THE BIG ISLAND FOR LOCALLY HEAVY SHOWERS OR
ISOLATED THUNDERSTORMS THIS AFTERNOON. TOMORROW...WEAK RIDGING ALOFT
WILL SPREAD OVER THE ISLANDS AND TRADE WINDS WILL SPREAD ACROSS THE
MAIN ISLANDS GIVING US ABOUT 36 HOURS OF RATHER DRY TRADEWIND
WEATHER.

MEANWHILE...THE TROUGH ALOFT NORTHWEST OF THE MAIN HAWAIIAN ISLANDS
WILL DIG DOWN. A LOW WILL CUT OFF NORTHWEST OF KAUAI NEAR 28N 168W
BY 2 AM SUNDAY MORNING. THIS LOW WILL DESTABILIZE THE ATMOSPHERE AND
CAUSE THE LOW LEVEL FLOW TO VEER TO EAST SOUTHEAST NEAR KAUAI AND
OAHU. THE COMPUTER MODELS SEEM TO BE SETTLING ON A FORECAST WHICH
HAS THE LOW MOVING OFF TO THE SOUTHWEST. THIS KEEPS THE LOW FAR
ENOUGH AWAY TO KEEP THE STRONGEST INSTABILITY WEST OF THE MAIN
HAWAIIAN ISLANDS AND KEEPS TRADE WINDS OVER THE BIG ISLAND AND MAUI.

BY MONDAY EVENING...TRADE WINDS WILL SPREAD BACK ACROSS ALL OF THE
MAIN HAWAIIAN ISLANDS AS HIGH PRESSURE AT THE SURFACE REBUILDS
NORTHEAST OF THE ISLANDS. THE GFS MEDIUM RANGE MODEL SUGGESTS THAT
THE HIGH WILL CONTINUE BUILDING WEST SOUTHWESTWARD DURING THE MIDDLE
OF NEXT WEEK. IF THAT TURNS OUT TO BE CORRECT...TRADE WINDS COULD
BECOME RATHER BREEZY BY LATE NEXT WEEK.

&&

.MARINE...
NORTHWEST SWELL AT BUOY 51001 HAS INCREASED OVER THE PAST FEW HOURS.
THIS SWELL WILL CAUSE SURF TO RISE ALONG NORTH AND WEST SHORES THIS
AFTERNOON...BUT HEIGHTS WILL REMAIN BELOW ADVISORY LEVELS. A LARGER
NORTHWEST SWELL WILL ARRIVE SUNDAY THAT WILL PROBABLY REQUIRE HIGH
SURF ADVISORIES.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
NONE.

DONALDSON