High Surf in Hawaii, December 6 to 7, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST TUE DEC 6 2011

.SYNOPSIS...
TRADE WIND WEATHER CONTINUES OVER THE STATE THROUGH THE WEEK AS A
SURFACE HIGH PRESSURE RIDGE REMAINS NORTH OF THE ISLANDS. PASSING
LOW CLOUDS AND SHOWERS WILL FAVOR WINDWARD AND MAUKA AREAS. WINDS
WILL INCREASE LATER IN THE WEEK AS THE SURFACE HIGH STRENGTHENS. A
LARGE NORTHWEST SWELL WILL AFFECT THE ISLANDS TODAY...WITH A BIGGER
ONE TO FOLLOW ON THURSDAY.

&&

.DISCUSSION...
TYPICAL TRADE WIND WEATHER CONTINUES OVER THE ISLANDS EARLY THIS
MORNING...AS A SURFACE HIGH PRESSURE REMAINS NORTH OF THE STATE.
LATEST SATELLITE IMAGERY AS WELL AS RADAR DATA INDICATE THERE IS AN
INCREASE IN LOW CLOUDS IN THE ISLAND VICINITY OVERNIGHT. THESE
CLOUDS...CARRIED BY THE TRADE WINDS...ARE PROVIDING SOME SHOWERS TO
THE ISLANDS...MAINLY WINDWARD AND MOUNTAIN. THERE ARE ALSO SOME
HIGH CLOUDS TRAVERSING THE ISLANDS AT TIMES AS WEAK FEATURES TRAVEL
ALONG AN UPPER LEVEL TROUGH WITH ITS AXIS LIES JUST EAST OF THE
STATE. THESE THIN HIGH CLOUDS WILL HAVE MINIMAL IMPACT ON THE
ISLAND WEATHER...EXCEPT TO FILTER THE SUNLIGHT AT TIMES. LATEST
RAINFALL TOTALS ACROSS THE STATE DOES NOT REVEAL ANY
SURPRISES...WITH RATHER LOW AMOUNTS REPORTED FOR MOST AREA. MORNING
SOUNDINGS FROM LIHUE AS WELL HILO BOTH REVEAL A SLIGHTLY UNSTABLE
AIR MASS...THOUGH MOISTURE IS A LITTLE LACKING AS THE PRECIPITABLE
WATERS ON BOTH SOUNDINGS ARE LESS THAN ONE AND A QUARTER INCH. THE
SURFACE RIDGE NORTH OF THE ISLANDS WILL CONTINUE TO BRING GENTLE TO
LOCALLY MODERATE TRADE WINDS TO THE STATE TODAY THROUGH
WEDNESDAY...WITH PASSING LOW CLOUDS AND SHOWERS AFFECTING MAINLY
WINDWARD AND MOUNTAIN AREAS.

WINDS ARE STILL EXPECTED TO INCREASE A BIT BEGINNING THURSDAY...AS
HIGH PRESSURE BUILDS NORTH OF THE STATE. WEAK UPPER LEVEL RIDGING IS
ALSO EXPECTED OVER THE ISLANDS AT THE SAME TIME...AND SHOULD RESULT
IN A MORE STABLE AIR MASS OVER THE ISLANDS. THUS THE ISLANDS MAY SEE
EVEN DRIER TRADE WIND WEATHER FOR THE LATER PART OF THE WEEK.

LATEST FORECAST CHARTS CONTINUE TO INDICATE WETTER TRADE WIND
WEATHER MAY RETURN BY THE END OF THE WEEKEND INTO EARLY NEXT
WEEK...AS A STRONGER UPPER LEVEL TROUGH PASSES OVER THE ISLANDS. AIR
MASS OVER THE ISLANDS IS EXPECTED TO BECOME MORE UNSTABLE...WHILE
HIGHER PRECIPITABLE WATERS MAY SPREAD OVER THE SOUTHERN ISLANDS
FROM THE SOUTH. THUS CONDITIONS MAY BECOME MORE FAVORABLE FOR
HEAVIER SHOWERS TO DEVELOP. WINDS ARE EXPECTED TO REMAIN RATHER
STRONG...AS A SURFACE HIGH PRESSURE STAYS FAR NORTH TO NORTHEAST OF
THE STATE.

&&

.MARINE...
THE FORERUNNER OF THE INCOMING LARGE NORTHWEST SWELL HAS REACHED
OAHU EARLIER THIS MORNING AS READINGS FROM THE WAIMEA BAY BUOY HAVE
INCREASED IN THE PAST FEW HOURS. THIS SWELL WILL BUILD THROUGHOUT
THE DAY...BRINGING ADVISORY LEVEL SURF TO THE NORTH AND WEST FACING
SHORES OF MOST OF THE SMALLER ISLANDS BY THIS AFTERNOON. A HIGH SURF
ADVISORY IS IN EFFECT FOR THE EXPOSED SHORES EARLY THIS MORNING
THROUGH EARLY WEDNESDAY.

A BIGGER LONG-PERIOD NORTHWEST SWELL IS STILL FORECAST TO ARRIVE
WEDNESDAY NIGHT. SURF HEIGHTS ALONG NORTH AND SOME WEST FACING
SHORES OF THE SMALLER ISLANDS ARE EXPECTED TO EXCEED ADVISORY LEVELS
THURSDAY AND FRIDAY. SOME OF THIS LONG-PERIOD SWELL ENERGY MAY REACH
PARTS OF THE KONA COAST OF THE BIG ISLAND...WHERE SURF HEIGHTS MIGHT
APPROACH THE HIGH SURF ADVISORY THRESHOLD OF 8 FEET THURSDAY NIGHT
AND FRIDAY.

THE CURRENT LARGE NORTHWEST SWELL...COMBINING WITH THE INCREASING
LOCAL WIND WAVES UNDER STRONGER TRADES...HAVE RESULT IN SMALL CRAFT
CONDITIONS FOR THE WINDWARD COASTAL WATERS AND CHANNELS OF KAUAI AND
MAUI COUNTY AS WELL AS OAHU. INCREASING WINDS BY THURSDAY WILL
PROBABLY BE STRONG ENOUGH TO BRING SMALL CRAFT CONDITIONS TO THE
TYPICALLY WINDY BIG ISLAND COASTAL WATERS...WHILE THE ARRIVAL OF THE
SECOND LARGER NORTHWEST SWELL WILL LIKELY RESULT IN THE COMBINED
SEAS OF 10 FEET OR GREATER FOR MOST OF THE COASTAL WATERS THURSDAY
AND FRIDAY. THE SMALL CRAFT ADVISORY WILL PROBABLY BE EXPANDED TO
COVER MOST OF THE COASTAL WATERS BY THEN.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY FOR NORTH AND WEST FACING SHORES OF NIIHAU AND
KAUAI AS WELL AS NORTH FACING SHORES OF OAHU MOLOKAI AND MAUI FROM
6 AM HST TUESDAY THROUGH 6 AM HST WEDNESDAY.

SMALL CRAFT ADVISORY THROUGH 6 AM HST WEDNESDAY FOR KAUAI NORTHWEST
AND WINDWARD WATERS...OAHU WINDWARD WATERS...MAUI COUNTY WINDWARD
WATERS...AND KAUAI AND KAIWI CHANNELS.

&&

HUI