High Surf in Hawaii, May 31, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
330 AM HST SUN MAY 31 2015

.SYNOPSIS...
LIGHT TO MODERATE TRADES WILL CONTINUE THROUGH THE NEXT COUPLE OF
DAYS. SEA BREEZES ARE LIKELY TO RETURN TODAY AND AGAIN ON MONDAY
WITH CLOUDS AND SHOWERS DEVELOPING OVER LEEWARD AREAS IN THE
AFTERNOON AND EVENING HOURS. THE TRADE WINDS WILL ALSO KEEP BRINGING
SHOWERS TO WINDWARD AND MOUNTAIN AREAS...ESPECIALLY AT NIGHT AND IN
THE MORNING HOURS.

&&

.DISCUSSION...
PREVAILING MODERATE TRADES CONTINUE TO BRING SHOWERS OVER WINDWARD
AND MOUNTAIN AREAS OF THE SMALLER ISLANDS...WITH POSSIBLE LOCALIZED
DOWNPOURS. RADAR AND SATELLITE DATA HAVE BEEN SHOWING PERSISTING
RAIN SHOWERS ANCHORED OVER THE CENTRAL AND EASTERN PORTIONS OF THE
KOOLAU MOUNTAINS IN OAHU DURING THE EVENING AND OVERNIGHT HOURS.
THE HEAVIEST RAIN FOCUSED OVER THE KOOLAU SLOPES NEAR KANEOHE AND
HEEIA. OTHER AREAS OF RAIN CAN STILL BE OBSERVED MOVING OVER THE
WINDWARD SLOPES OF HALEAKALA IN MAUI. MOST AREAS OF THE BIG ISLAND
ARE STILL EXPERIENCING CLOUDY PERIODS...BUT RAINFALL REMAINS
SPORADIC ON RADAR IMAGERY.

THE 12Z SOUNDINGS FROM HILO AND LIHUE SHOW PWATS INCREASING TO NEAR
1.5 INCHES...DUE IN PART TO THE PRESENCE OF INCREASED MOISTURE
ASSOCIATED WITH THE REMNANTS OF A FORMER COLD FRONT BOUNDARY
LINGERING ABOUT 300 MILES E OF THE BIG ISLAND. ELEVATED WEAK
INVERSIONS AROUND 10 THOUSAND FEET ARE ALSO ALLOWING FOR THE LARGER
SHOWERS TO MOVE BEYOND THE MOUNTAINS AND REACH LEEWARD AREAS AT
TIMES.

THE W EDGE OF THE REMNANT BOUNDARY IS MARKED BY A 100 MILE WIDE BAND
OF CLOUDS ORIENTED FROM E TO W NOW LOCATED ACROSS THE W HALF OF THE
ISLAND CHAIN...MAINLY AROUND KAUAI AND OAHU. THIS FEATURE WILL
LINGER OVER THE AREA AND CONTINUE TO SUPPORT SHOWER ACTIVITY TODAY.
IT WILL LIKELY SLOWLY SLIDE S...AND BECOME STATIONARY AROUND MAUI
AND THE BIG ISLAND BY MON AS SFC HIGH PRESSURE FAR NW OF THE STATE
BEGINS MOVING CLOSER TO THE AREA. MEANWHILE...MODELS CONTINUE TO
SUGGEST THE DEVELOPMENT OF A DEEPENING UPPER LEVEL TROUGH SEVERAL
HUNDRED MILES N OF THE ISLANDS....WITH AN ACCOMPANYING CLOSED LOW
MIGRATING E DURING THE FIRST HALF OF THE WORK WEEK. IN RESPONSE...
MODEL SOLUTIONS ARE TRYING TO GENERATE A SFC TROUGH...WHILE
ENERGIZING THE AFOREMENTIONED STALLED FRONTAL REMNANT AS THE
TROUGH/LOW COMPLEX MOVES TO THE N OF THE ISLANDS. THIS SYNOPTIC
SCENARIO WILL KEEP GOOD POTENTIAL FOR ENHANCED SHOWER ACTIVITY
ACROSS THE MAIN HAWAIIAN ISLANDS IN THE TUE-WED TIMEFRAME. THIS
SHOULD ALSO KEEP A LIGHT TRADE WIND REGIME IN PLACE THROUGH MID
WEEK. THEREFORE...EXPECT A COMBINATION OF ENHANCED WINDWARD/MOUNTAIN
SHOWERS...AND AFTERNOON SEA BREEZE-INDUCED SHOWERS OVER LEEWARD
AREAS EACH DAY.

THE BAND OF CLOUDS AND MOISTURE FINALLY BEGINS DISSIPATING TOWARDS
THE END OF THE WORK WEEK AS THE UPPER LOW/TROUGH COMPLEX MOVES
FURTHER AWAY FROM THE AREA. A MORE ROBUST TRADE WIND FLOW SHOULD
GRADUALLY RETURN NEXT WEEKEND AS THE HIGH PRESSURE FAR N OF THE
ISLANDS STRENGTHENS IN THE WAKE OF THE TROUGH.

&&

.AVIATION...
LIGHT TO MODERATE TRADES WILL PERSIST OVER THE AREA TODAY. RIDING ON
THE TRADE FLOW...REMNANT SHOWERY LOW CLOUDS FROM AN OLD FRONT WILL
MAINLY AFFECT WINDWARD AND MAUKA SECTIONS ACROSS THE STATE...
BRINGING TEMPO MVFR CONDITIONS IN LOWER CEILINGS AND VISIBILITIES.
VFR WILL PREVAIL OTHERWISE.

BECAUSE OF THE CONDITIONS DESCRIBED ABOVE...AN AIRMET FOR MOUNTAIN
OBSCURATION REMAINS POSTED FOR NORTH THRU EAST SECTIONS ON ALL ISLES
EXCEPT LANAI.

&&

.MARINE...
THE LONG-PERIOD SOUTH SOUTHWEST SWELL CONTINUES TO BUILD ACROSS THE
MAIN HAWAIIAN ISLAND CHAIN THIS MORNING. THE BUOYS SOUTH OF THE
HAWAIIAN ISLANDS...INCLUDING BUOYS 51002...51003 AND 51004...AS WELL
AS THE BARBERS POINT BUOY...ALL CONTINUE TO DETECT INCREASING ENERGY
WITHIN THE 20 SECOND AND HIGHER BANDS. AS THIS SWELL CONTINUES TO
BUILD...SURF HEIGHTS ARE EXPECTED CONTINUE RISING...AND WILL LIKELY
REACH THE HIGH SURF CRITERIA BY DAYBREAK THIS MORNING. BASED ON THE
LATEST GUIDANCE FROM THE WAVE WATCH III MODEL...THIS SWELL IS
EXPECTED TO BUILD THROUGH TODAY...PEAK MONDAY...AND THEN GRADUALLY
DIMINISH TUESDAY AND WEDNESDAY. NOTE THAT WITH OPEN OCEAN SWELL
HEIGHTS EXPECTED TO PEAK NEAR 5 FEET...THIS SWELL MAY CAUSE MODERATE
SURGES IN EXPOSED SOUTH FACING HARBORS. IN ADDITION...LARGE BREAKING
WAVES MAY OCCUR IN AND NEAR SOUTH FACING CHANNEL ENTRANCES. MARINERS
AND BEACHGOERS SHOULD BE ALERT TO THE FACT THAT THIS IS EXPECTED TO
BE THE LARGEST SOUTHERN HEMISPHERE SWELL SO FAR THIS SEASON. ALSO...
LARGE TIDAL CHANGES WILL ALSO LEAD TO LOCALLY STRONG CURRENTS IN
THE SURF ZONE. A MARINE WEATHER STATEMENT HAS BEEN ISSUED TO
DESCRIBE THESE POTENTIAL HAZARDS FOR MARINERS AND BEACHGOERS.

OTHERWISE...SMALL AND RELATIVELY SHORT-PERIOD NORTHWEST SWELLS WILL
ARRIVE INTO EARLY THIS WEEK. THESE SWELLS WILL SUPPORT SMALL SURF
ALONG MOST NORTH FACING SHORES. FINALLY...BASED ON THE LATEST
FORECAST...WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW THE SMALL
CRAFT ADVISORY /SCA/ CRITERIA THROUGH MID-WEEK.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY IN EFFECT UNTIL 6 PM HST MONDAY FOR SOUTH
FACING SHORES OF ALL ISLANDS.

&&

SYNOPSIS/DISCUSSION...REYNES
MARINE...HOUSTON
AVIATION...KINEL