High Surf in Hawaii, January 24 to 29, 2016

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
358 PM HST SUN JAN 24 2016

.SYNOPSIS...
DRY...STABLE...AND HAZY CONDITIONS WITH LIGHT WINDS WILL DOMINATE
AHEAD OF AN APPROACHING WEAK FRONT. THE FRONT WILL PRODUCE MODEST
SHOWERS ACROSS NORTH AND NORTHEAST FACING SLOPES AS IT REACHES
KAUAI THIS EVENING...THEN MOVES TO OAHU AND MOLOKAI LATE. THE
FRONT IS EXPECTED WEAKEN AS IT STALLS NEAR THE EASTERN END OF THE
ISLAND CHAIN ON MONDAY. A SURFACE RIDGE WILL QUICKLY REDEVELOP
OVER THE ISLANDS BY TUESDAY...CREATING A STABLE AND RATHER DRY
LAND AND SEA BREEZE PATTERN THROUGH AT LEAST FRIDAY.

&&

.DISCUSSION...
TONIGHT THROUGH MONDAY...
A WEAK FRONT...CURRENTLY ABOUT 60 MILES NORTH OF KAUAI...WILL
AFFECT THE NORTHERN END OF THE ISLAND CHAIN TONIGHT. THE FRONT
CONTINUES TO LOOK UNIMPRESSIVE ON SATELLITE IMAGERY...WITH BROKEN
CUMULUS CLOUDS REACHING BETWEEN 9000 TO 12000 FT AND PRECIPITABLE
WATER VALUES OF AROUND 1.25 INCHES. THIS FEATURE SHOULD PRODUCE
MODEST SHOWERS ALONG NORTH AND NORTHEAST FACING SLOPES OF KAUAI
DURING THE EVENING THEN ON OAHU AND MOLOKAI AFTER MIDNIGHT.
CHANCES FOR RAINFALL REMAIN LOW ACROSS LEEWARD SECTIONS. MODERATE
NORTHERLY WINDS WILL PUSH IN BEHIND THE FRONT BUT WILL BE SHORT-
LIVED. THE MAIN WIND IMPACTS WILL BE SEEN ON THE HIGH SUMMITS OF
THE BIG ISLAND...WHERE NORTHWEST TO NORTH WINDS WILL REACH
ADVISORY STRENGTH DURING THE EVENING...AND WITH THE GFS SHOWING
600 MB WINDS OF 30 TO 35 KT DURING PAST COUPLE OF RUNS...HIGH WIND
WARNING CONDITIONS ARE NOT OUT OF THE QUESTION FOR LATE TONIGHT
AND EARLY MONDAY.

AHEAD OF THE FRONT...EXPECT DRY...STABLE...AND HAZY CONDITIONS TO
PREVAIL THROUGH THE NIGHT OVER MAUI AND THE BIG ISLAND. LIGHT
WINDS WILL LEAD TO OVERNIGHT LAND BREEZES THAT WILL PROMOTE
CLEARING AND LITTLE...IF ANY RAINFALL.

THE FRONT FALL APART ON MONDAY...AND WINDS WILL RAPIDLY DIMINISH
AS A SURFACE RIDGE BUILDS IN FROM THE WEST. THE GFS AND ECMWF ARE
SHOWING SOME DIFFERENCES IN JUST HOW FAR THE MOISTURE WILL
REACH...WITH THE GFS PUSHING IT DOWN TO THE BIG ISLAND AND THE
ECMWF HANGING IT BACK OVER THE CENTRAL ISLANDS. THE FORECAST LEANS
MORE TOWARD THE GFS...WHICH HAS HANDLED THE MOISTURE FIELDS OF THE
PAST FEW SHALLOW FRONTS WELL. EITHER WAY...ANY CONTINUED RAINFALL
WOULD BE LIGHT AND CONDITIONS WILL BE STABLE AS BUILDING RIDGING
ALOFT WILL DOMINATE. BIG ISLAND SUMMIT WINDS WILL ALSO BE ON A
DECLINE IN THE AFTERNOON AS THE UPPER LEVEL TROUGH DRIVING THE
FRONT QUICKLY DEPARTS TO THE EAST.

MONDAY NIGHT THROUGH SATURDAY...
A RATHER DRY AND STABLE WEATHER PATTERN WILL RETURN FOR AT LEAST
THE WORK WEEK. A STRONG WEST TO EAST FLOWING JET STREAM ALOFT WILL
REMAIN CENTERED BETWEEN 30N AND 40W...KEEPING THE SURFACE RIDGE
OVER THE ISLANDS FROM LATE MONDAY NIGHT INTO SATURDAY. THE RIDGE
SHOULD BE OVER THE CENTRAL ISLANDS FOR MUCH OF THIS TIME...WHICH
WILL CREATE A GENTLE...GENERALLY SOUTHERLY FLOW THAT WILL PRODUCE
PERIODS OF VOLCANIC HAZE FOR MOST OF THE STATE. RIDGING ALOFT WILL
MAINTAIN STABLE CONDITIONS...AND THE GFS AND ECMWF SHOW LITTLE
AVAILABLE MOISTURE. AS A RESULT...A RATHER DRY LAND AND SEA BREEZE
PATTERN WILL PREVAIL.

UNCERTAINTY INCREASES SOMEWHAT HEADING INTO NEXT WEEKEND. THE GFS
AND ECMWF ARE SHOWING A FRONT STALLING NEAR OR JUST NORTH OF KAUAI
ON FRIDAY AND SATURDAY. THERE IS A CHANCE THAT PORTIONS OF THE
ISLAND CHAIN COULD SEE INCREASED MOISTURE...BUT ODDS FAVOR
CONTINUED DRY WEATHER.

&&

.AVIATION...
A WEAK FRONT WILL BRING AREAS OF MVFR CIGS AND VIS IN SHRA TO
NORTH AND NORTHEAST FACING SLOPES OF KAUAI THIS EVENING...THEN TO
OAHU AND MOLOKAI LATE. THE WEAKENING FRONT WILL PRODUCE SOME MVFR
CIGS OVER NORTHEAST FACING SLOPES OF MOLOKAI...MAUI AND THE BIG
ISLAND ON MONDAY. VFR WILL PREVAIL ELSEWHERE.

WITH WINDS ALOFT INCREASING...AIRMET TANGO FOR UPPER LEVEL
TURBULENCE NEAR THE BIG ISLAND SUMMITS WILL REMAIN IN PLACE
THROUGH THE NIGHT AND LIKELY MONDAY.

&&

.MARINE...
ALTHOUGH A WEAK FRONT WILL BRING A BRIEF PERIOD OF MODERATE
NORTHERLY WINDS TONIGHT...THE MAIN STORY CONTINUES TO BE A PAIR
OF VERY LARGE NORTHWEST SWELLS DUE THIS WEEK. AFTER RUNNING
BEHIND OUR PREDICTED SCHEDULE SINCE LAST NIGHT...THE SWELL REACHED
13 FT AT 16 SECONDS AS OF 3 PM AT BUOY 51101...FINALLY CATCHING UP
TO THE WAVEWATCH FORECAST FOR THIS POINT. THIS IS NO SURPRISE...AS
SWELLS HAVE TENDED TO ARRIVE LATER THAN EXPECTED SO FAR THIS
WINTER. DUE TO THE DELAY IN THE SWELL ENERGY...SURF WILL LIKELY
REACH WARNING LEVEL SURF LEVELS ON KAUAI AFTER DARK AND ON OAHU
AND MAUI COUNTY AROUND MIDNIGHT...WITH THE PEAK OF THE EVENT
EXPECTED DURING THE DAY ON MONDAY. A HIGH SURF ADVISORY REMAINS
POSTED FOR MOST NORTH AND WEST FACING SHORES OF THE SMALLER
ISLANDS THROUGH MONDAY NIGHT...AND A HIGH SURF ADVISORY HAS BEEN
ISSUED FOR WEST FACING SHORES OF THE BIG ISLAND.

A SMALL CRAFT ADVISORY /SCA/ FOR SEAS OF 10 FT OR MORE IS IN
EFFECT FOR WATERS EXPOSED TO THE BUILDING NORTHWEST SWELL. THE
SCA COULD BRIEFLY COME DOWN ON TUESDAY...BUT IT WILL NEED TO BE
POSTED ONCE AGAIN FOR ANOTHER...POTENTIALLY LARGER...NORTHWEST
SWELL DUE ON WEDNESDAY INTO THURSDAY. WINDS WILL REMAIN BELOW SCA
STRENGTH THROUGH THE WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF WARNING UNTIL 6 AM HST TUESDAY FOR NORTH AND WEST
FACING SHORES OF NIIHAU KAUAI OAHU AND MOLOKAI AND NORTH FACING
SHORES OF MAUI.

HIGH SURF ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM HST TUESDAY FOR
WEST FACING SHORES OF THE BIG ISLAND.

WIND ADVISORY FROM 6 PM THIS EVENING TO 6 PM HST MONDAY FOR THE
BIG ISLAND SUMMITS.

SMALL CRAFT ADVISORY UNTIL 6 AM HST TUESDAY FOR WATERS AROUND
KAUAI AND OAHU AND FOR WATERS NORTH AND EAST OF MAUI COUNTY AND
THE BIG ISLAND.

&&

WROE