High Surf in Hawaii, December 28 to 31, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
410 AM HST MON DEC 28 2009

.SYNOPSIS...
A DRY WEATHER PATTERN WILL CONTINUE ACROSS THE ALOHA STATE THROUGH
TONIGHT AS A SURFACE RIDGE REMAINS IN THE VICINITY OF THE MAIN
HAWAIIAN ISLANDS. HAZY CONDITIONS DUE TO VOG ARE EXPECTED TO SPREAD
ACROSS THE SMALLER HAWAIIAN ISLANDS BY THIS AFTERNOON. A WEAKENING
FRONT IS EXPECTED TO BRING AN INCREASE IN CLOUD COVER AND SHOWERS
OVER THE WESTERN END OF THE STATE AS IT APPROACHES KAUAI TUESDAY
NIGHT AND WEDNESDAY. THIS FRONT IS FORECAST TO DISSIPATE NEAR OAHU
WEDNESDAY NIGHT. LIGHT WINDS AND HAZY CONDITIONS  WILL LIKELY
CONTINUE ACROSS MOST OF THE STATE THROUGH NEW YEARS EVE.

&&

.DISCUSSION...
SATELLITE IMAGERY INDICATES A LARGE AREA OF MOSTLY STABLE LOW CLOUDS
ACROSS MOST OF THE MAIN HAWAIIAN ISLANDS EARLY THIS MORNING. THESE
LOW CLOUDS...WHICH ARE BEING TRANSPORTED NORTHWARD...ARE MAINLY
AFFECTING PORTIONS OF OAHU...MAUI AND THE BIG ISLAND. RADAR
INDICATES THERE ARE SOME LIGHT SHOWERS EMBEDDED WITHIN THE CLOUDS IN
THE VICINITY OF MAUI AND OVER THE WINDWARD AND SOUTHERN BIG ISLAND
COASTAL WATERS.

A NEARLY STATIONARY EAST NORTHEAST TO WEST SOUTHWEST ORIENTED
SURFACE RIDGE APPEARS TO BE IN THE VICINITY KAUAI BASED ON LOOPS OF
SATELLITE IMAGERY...SURFACE OBSERVATIONS AND A SCATTEROMETER PASS
OVER THE WESTERN HALF OF THE ISLAND CHAIN SEVERAL HOURS AGO. LATE
AFTERNOON VISIBLE SATELLITE IMAGERY ON SUNDAY DID NOT SHOW ANY
EVIDENCE OF A HAZE SIGNATURE DENOTING VOG FROM BIG ISLAND VOLCANIC
SOURCES. THIS HAZE FEATURE COULD HAVE BEEN MASKED BY THE LOW CLOUDS
THAT WERE SOUTH OF LANAI AND OAHU AT THAT TIME. THE CURRENT FORECAST
CONTINUES TO BRING THE VOG INTO PARTS OF THE SMALLER ISLANDS...
INCLUDING OAHU...BY THIS AFTERNOON. THE LIGHT WINDS ACROSS THE STATE
WILL ALLOW THE DEVELOPMENT OF LOCAL DAYTIME SEA BREEZES AND NIGHT
TIME LAND BREEZES. AS A RESULT...CLOUD COVER WILL LIKELY INCREASE
OVER INTERIOR SECTIONS OF MANY OF THE ISLANDS DURING THE AFTERNOON
HOURS.

BASED ON THE LATEST RUNS OF THE NAM...GFS AND ECMWF MODELS...THE
SURFACE RIDGE IS EXPECTED TO SHIFT SOUTHWARD TO THE BIG ISLAND BY
TUESDAY AND TUESDAY NIGHT AS A COLD FRONT APPROACHES KAUAI. THE GFS
AND ECMWF MODELS APPEAR TO INDICATE THIS FRONT WILL BE WEAKENING AS
IT REACHES KAUAI WEDNESDAY...AND WILL LIKELY DISSIPATE IN THE
VICINITY OF OAHU WEDNESDAY NIGHT. THE GFS MODEL DEPICTS A WEAK
SURFACE RIDGE NEAR THE ISLANDS THURSDAY...WHICH WOULD MAINTAIN LIGHT
WINDS ON NEW YEAR/S EVE. HOWEVER...THE ECMWF INDICATES SOUTHERLY
WINDS ON THURSDAY AHEAD OF ANOTHER FRONT...WHICH MAY REACH KAUAI
THURSDAY NIGHT. SINCE THE GFS MODEL HAS PROVIDED DIFFERING SOLUTIONS
FROM MODEL RUN TO MODEL RUN...AND IT HAS DIFFERENT SOLUTIONS
COMPARED WITH THE ECMWF...THERE REMAINS UNCERTAINTY IN THE NEW
YEAR/S EVE AND NEW YEAR/S DAY FORECASTS AT THIS TIME. FOR PLANNING
PURPOSES...ASSUME LIGHT WINDS WILL BE THE RULE ACROSS MOST AREAS OF
THE STATE ON NEW YEAR/S EVE NIGHT DURING THE HOLIDAY FIREWORKS
EXTRAVAGANZA...WHICH WILL TAKE PLACE OVER MANY PARTS OF THE STATE.

&&

.MARINE...
A REINFORCING NORTHWEST SWELL HAS ARRIVED AT BACK UP BUOY NUMBER
51101 LOCATED NORTHWEST OF KAUAI EARLY THIS EVENING. THE MOST RECENT
OBSERVATIONS FROM THAT MOORED BUOY INDICATED THE SWELL HEIGHT IS 8
TO 10 FEET WITH A PERIOD OF 16 SECONDS FROM AN AZIMUTH OF 300
DEGREES. FORERUNNERS FROM THIS SWELL ARRIVED IN THE ISLANDS A FEW
HOURS AGO BASED ON READINGS FROM THE WAIMEA BAY BUOY. SURF HEIGHTS
PRODUCED BY THIS SWELL ARE FORECAST TO REACH THE HIGH SURF ADVISORY
THRESHOLDS ALONG NORTH AND WEST FACING SHORES OF NIIHAU AND KAUAI
THIS MORNING...AND ALONG NORTH AND WEST FACING SHORES OF OAHU AND
MOLOKAI...AND ALONG NORTH FACING SHORES OF MAUI BY THIS AFTERNOON.
THE WAVEWATCH III MODEL INDICATES THE SWELL WILL CONTINUE TO PRODUCE
THIS LARGE SURF ALONG THE AFFECTED SHORELINES THROUGH TONIGHT.

AN EVEN LARGER REINFORCING NORTHWEST SWELL IS EXPECTED TO ARRIVE IN
THE ISLANDS WEDNESDAY MORNING. BASED ON THE WAVEWATCH III MODEL...
THIS SWELL COULD PRODUCE SURF ABOVE THE HIGH SURF ADVISORY
THRESHOLDS ALONG THE SAME SHORELINES OF THE SMALLER ISLANDS FROM
WEDNESDAY THROUGH THURSDAY NIGHT. IN ADDITION...THE WAVE WATCH III
MODEL SUGGESTS THIS SWELL MIGHT PUSH SURF HEIGHTS ALONG PARTS OF THE
WEST FACING SHORES OF THE BIG ISLAND NEAR THE HIGH SURF ADVISORY
THRESHOLD BY LATE WEDNESDAY OR THURSDAY.

BASED ON THE CURRENT FORECAST...THE COMBINED SEAS RESULTING FROM THE
FIRST NORTHWEST SWELL AND THE LOCAL WIND WAVES WILL REMAIN BELOW THE
SMALL CRAFT ADVISORY...OR SCA...THRESHOLD OF 10 FEET TODAY AND
TONIGHT. HOWEVER...THE LARGER NORTHWEST SWELL ARRIVING MID-WEEK
WOULD LIKELY RESULT IN SCA CONDITIONS OVER THOSE HAWAIIAN WATERS
EXPOSED TO IT STARTING WEDNESDAY AFTERNOON...AND CONTINUING THROUGH
THURSDAY NIGHT.

FINALLY...A SMALL...BUT LONG PERIOD...OUT OF SEASON SOUTH SOUTHWEST
SWELL IS EXPECTED TO ARRIVE TODAY. THIS SWELL IS FORECAST TO PRODUCE
A NOTICEABLE INCREASE IN SURF HEIGHTS ABOVE TYPICAL WINTER TIME
BACKGROUND LEVELS ALONG SOUTH FACING SHORES DURING THE FIRST HALF OF
THE WORK WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY THROUGH 600 AM HST TUESDAY FOR NORTH AND WEST
FACING SHORES OF NIIHAU...KAUAI...OAHU AND MOLOKAI...AND NORTH
FACING SHORES OF MAUI.

&&

HOUSTON