High Surf in Hawaii, December 2 to 6, 2004

HAWAIIAN ISLANDS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST THU DEC 2 2004

.SYNOPSIS...
A STRONG HIGH...FAR NORTHEAST OF THE ISLANDS...WILL MOVE SOUTHWEST
AND SLOWLY WEAKEN. THE HIGH WILL PRODUCE BREEZY WEATHER THROUGH
EARLY NEXT WEEK. A TROUGH ALOFT OVER THE ISLANDS IS KEEPING THE
ATMOSPHERE SLIGHTLY UNSTABLE AND PRODUCING PATCHY HIGH CLOUDS. THE
TROUGH WILL MOVE SOUTH SLOWLY. AS IT DOES...THE HIGH CLOUDS WILL
DISSIPATE...THE ATMOSPHERE WILL BECOME MORE STABLE AND SHOWERS WILL
DECREASE.

&&

.SHORT TERM...
SATELLITE IMAGERY SHOWS HIGH CLOUDS HAVE CLEARED THE ISLANDS FROM
KAUAI TO MAUI BUT REMAIN OVER THE BIG ISLAND...BLOCKING OUR VIEW OF
LOWER LEVEL FEATURES THERE. ACCORDING TO UPPER LEVEL HUMIDITY
FORECASTS FROM THE COMPUTER MODELS...THE HIGH CLOUDS WILL CONTINUE TO
SHIFT SOUTHWARD AND DISSIPATE. THE ISLANDS SHOULD BE CLEAR OF HIGH
CLOUDS BY TONIGHT. LOW CLOUD COVERAGE HAS ALSO DECREASED OVER THE
PAST 24 HOURS BUT RADAR AND SATELLITE IMAGERY STILL SHOW SCATTERED
UNSTABLE LOW CLOUDS UPSTREAM TO THE EAST OF THE ISLANDS. THESE
CLOUDS WILL BRING SHOWERS TO WINDWARD AREAS...AND WITH THE STRONG
TRADE WINDS...SOME WILL SPREAD LEEWARD ON THE SMALLER ISLANDS.

&&

.LONG TERM...
WATER VAPOR IMAGERY SHOWS A LOW ALOFT CENTERED ABOUT 1100 MILES
EAST NORTHEAST OF HILO WITH A TROUGH EXTENDING WEST SOUTHWEST OVER
THE MAIN HAWAIIAN ISLANDS. THE MODELS CONTINUE TO DO WELL DEPICTING
THE UPPER LEVEL PATTERN. A RIDGE ALOFT NORTHWEST OF THE ISLANDS IS
STRENGTHENING WITH AN ANTICYCLONE BUILDING ABOUT 550 MILES NORTH OF
KAUAI. AS THE HIGH BUILDS...THE TROUGH OVER THE ISLANDS WILL SHIFT
SOUTHWARD. AS THESE CHANGES OCCUR ALOFT...THE ATMOSPHERE OVER THE
MAIN HAWAIIAN ISLANDS WILL BECOME MORE STABLE AND THERE WILL BE A
DEEP LAYER OF NORTHEAST FLOW OVER THE ISLANDS.

THE SURFACE ANALYSES SHOW A STRONG 1038 MB SURFACE HIGH CENTERED FAR
NORTHEAST OF THE HAWAIIAN ISLANDS. THE HIGH WILL GRADUALLY MOVE
SOUTHWEST. ALTHOUGH THE HIGH WILL ALSO BE WEAKENING SLOWLY...THE
PRESSURE GRADIENT OVER THE MAIN HAWAIIAN ISLANDS WILL REMAIN TIGHT
ENOUGH TO KEEP RATHER STRONG TRADE WINDS BLOWING OVER THE ISLANDS
THROUGH EARLY NEXT WEEK. WITH STRONG TRADE WINDS AND A STABLE
ATMOSPHERE...CONDITIONS WILL BE FAVORABLE FOR THE WINDS TO
ACCELERATE DOWNSLOPE OVER THE LEEWARD SIDES OF THE ISLANDS. WIND
ADVISORIES MAY BE REQUIRED FOR THE DOWNSLOPE WINDS. THE TRADE WINDS
WILL GRADUALLY DECREASE NEXT WEEK AS A NEW TROUGH DIGS SOUTHEASTWARD
AND WEAKENS THE SUBTROPICAL RIDGE.

&&

.MARINE...
STRONG TRADE WINDS WILL CONTINUE. AS A RESULT SMALL CRAFT ADVISORIES
WILL REMAIN UP FOR ALL HAWAIIAN WATERS.

SURF WILL REMAIN ABOVE HIGH SURF ADVISORY CRITERIA ALONG EAST
FACING SHORES THROUGH THE WEEKEND. A NORTHWEST SWELL HITTING THE
ISLANDS WILL PRODUCE HIGH SURF ALONG NORTH FACING SHORES FROM
NIIHAU TO MAUI TODAY. THE LATEST BUOY DATA SUGGEST THAT SURF WILL
NOT REACH HIGH SURF CRITERIA ALONG WEST FACING SHORES AND ALONG
NORTH FACING SHORES OF THE BIG ISLAND. WE ARE DROPPING ADVISORIES
FOR THOSE AREAS AT 4 AM.

&&

.AVIATION...
WITH STRONG TRADE WINDS AND STABLE CONDITIONS IT MAY BECOME QUITE
TURBULENT AT LOW LEVELS OVER AND DOWNSTREAM OF THE ISLANDS. A SIGMET
FOR LOW LEVEL TURBULENCE MAY BE REQUIRED.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY...EAST FACING SHORES OF KAUAI OAHU MOLOKAI MAUI
AND THE BIG ISLAND TODAY THROUGH MONDAY NIGHT.

HIGH SURF ADVISORY...NORTH FACING SHORES OF NIIHAU KAUAI OAHU
MOLOKAI MAUI TODAY THROUGH TONIGHT.

SMALL CRAFT ADVISORY FOR ALL HAWAIIAN WATERS.

DONALDSON