High Surf in Hawaii, November 4 to 7, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST SUN NOV 4 2012

.SYNOPSIS...
LIGHT WINDS AND DRY WEATHER WILL PERMIT VOLCANIC HAZE TO LINGER
OVER THE STATE THROUGH EARLY THIS AFTERNOON. CLOUDS FROM A
DISSIPATING FRONT MAY BRING A FEW SHOWERS TO KAUAI COUNTY AS EARLY
AS TONIGHT. MORE GENERALLY...TRADE WINDS WILL RETURN ACROSS THE
STATE BY AROUND MONDAY...AND TYPICAL WINDWARD SHOWERS SHOULD FOLLOW
BY WEDNESDAY.

&&

.DISCUSSION...
SURFACE OBSERVATIONS AROUND THE MAIN HAWAIIAN ISLANDS STILL REPORTED
LIGHT AND VARIABLE WINDS. PRESSURE TRENDS SUGGESTED A GRADUAL
RESTORATION OF NORTHEAST PREVAILING WINDS...BUT LITTLE CHANGE AT
FIRST. MOST OF THE MOMENTUM DETECTED BY RADIOSONDE THROUGH THE MIXED
LAYER REMAINED SOUTHERLY HOWEVER...AND ABOVE THE SURFACE.

PRECIPITATION ACROSS THE STATE REMAINED LIGHT...BUT A FEW GAUGES
REPORTED ACCUMULATION ON THE BIG ISLAND. SOUNDINGS STILL RECORDED A
DRY AIR MASS...AND SATELLITE ESTIMATES SUGGESTED LITTLE ATMOSPHERIC
MOISTURE FOR SOME DISTANCE OUT TO SEA...THOUGH SOME SLIGHT
MOISTENING WAS PRESENT TO THE SOUTHEAST. THE INVERSION ROSE SLIGHTLY
AGAIN AT HILO...WHILE REMAINING NEAR ITS TYPICAL HEIGHT OVER LIHUE.
THE SLIGHTLY INCREASED POTENTIAL FOR SHOWER DEVELOPMENT THIS
MORNING AS COMPARED TO 24 HOURS AGO LIKELY WILL NOT BE REACHED
BECAUSE OF THE OTHER CONSTRAINTS THOUGH.

CONVECTION FIRED UP ALONG THE FRONT TO THE NORTHWEST...EVEN THOUGH
GUIDANCE AGREED THAT THE SUPPORTING TROUGH ALOFT HAD REACHED ITS
SOUTHWARD LIMIT...AND WILL MOVE AWAY TO THE NORTHEAST AS THE
MID-LEVEL RIDGE REBUILDS BEHIND IT THROUGH THE NEXT 18 TO 30 HOURS.
AT THIS RATE...SOME OF THE REMNANT MOISTURE PROBABLY WILL MAKE IT TO
KAUAI...IF ONLY ON RETURNING TRADE WINDS.

SPEAKING OF THE TRADES...THEY SHOULD RETURN TO THE STATE FROM LATE
TONIGHT INTO TUESDAY AS RIDGING REBUILDS THROUGH MOST OF THE
ATMOSPHERE. EVENTUALLY...OROGRAPHIC FORCING WILL SQUEEZE OUT A
LITTLE RAIN OVER WINDWARD SLOPES...BUT THE DRY AIR MASS PERSISTING
OVER THE STATE WILL NOT SUPPORT MUCH SHOWER DEVELOPMENT SOUTH OF
KAUAI UNTIL MID-WEEK...THOUGH THE BIG ISLAND CAN EXPECT THE
SECOND-HIGHEST ACCUMULATION.

BY LATE IN THE WEEK...MODELS INCREASINGLY DEPICT A BLOCKING PATTERN
FORMING ALOFT TO THE EAST OF THE STATE. OVERALL...SUCH A DEVELOPMENT
WOULD TEND TO PRESERVE THE STATUS QUO AT THE SURFACE...WHICH BY THAT
POINT IS EXPECTED TO CONSIST OF MODERATE TRADE-WIND CONDITIONS.

&&

.MARINE...
A NORTH SWELL BUILDING TONIGHT WILL BRING ADVISORY-LEVEL SURF TO
KAUAI...OAHU...MOLOKAI...AND MAUI TODAY. THE NORTHERLY COMPONENT OF
THE SWELL WILL BRING SURF TO NORTH-FACING SHORES...INCLUDING
NORTH-FACING SHORES OF BEACHES ALONG THE WINDWARD SIDE OF OAHU.
ADVISORY-LEVEL SURF ALSO IS EXPECTED TO REACH SOME OF THE
WEST-FACING SHORES OF KAUAI AND MOLOKAI...WHICH ARE EXPOSED TO THIS
NORTH SWELL. BECAUSE KAUAI WILL BLOCK THIS NORTHERLY SWELL...MOST
LIKELY IT WILL NOT REACH WEST-FACING SHORES OF OAHU.

THE SWELL LIKELY WILL BRING ADVISORY-LEVEL SURF TO THE BIG ISLAND BY
LATE TODAY. AT THIS TIME THE BIG ISLAND IS NOT INCLUDED IN THE SURF
ADVISORY...BUT LIKELY WILL BE ADDED LATER.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST MONDAY FOR KAUAI WINDWARD-
KAUAI LEEWARD-OAHU NORTH SHORE-OAHU KOOLAU-OLOMANA-MOLOKAI-MAUI
WINDWARD WEST-MAUI CENTRAL VALLEY-WINDWARD HALEAKALA.

&&

RYSHKO