High Surf in Hawaii, June 5 to 7, 2011

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE HONOLULU HI
610 AM HST SUN JUN 5 2011

.SYNOPSIS...
A LOW ALOFT IS SLOWLY MOVING EAST. WEATHER OVER HAWAII WILL IMPROVE
SLOWLY TODAY AND TONIGHT. DAYTIME HEATING COULD STILL LEAD TO
ISOLATED HEAVY SHOWERS OVER LEEWARD AND INTERIOR PORTIONS OF THE
ISLANDS TODAY...ESPECIALLY OVER THE BIG ISLAND. WINDS WILL REMAIN
ON THE LIGHTER SIDE THROUGH TUESDAY...BEFORE TRADE WINDS
STRENGTHEN LATER IN THE WEEK. A SLIGHTLY UNSTABLE ATMOSPHERE WILL
KEEP SHOWERS WETTER THAN NORMAL THROUGH THE WEEK.

&&

.DISCUSSION...
AN UPPER LEVEL LOW IS MAINTAINING AN UNSTABLE ATMOSPHERE...BUT
IS RELINQUISHING SOME OF ITS GRASP OVER THE STATE. WARMER
AIR ALOFT IS MOVING IN FROM THE WEST AS THE UPPER LOW MOVES SLOWLY
EAST. THE OVERNIGHT LIHUE SOUNDING BEARS THIS OUT SHOWING 2-3
DEGREE C WARMING IN THE MID AND UPPER ATMOSPHERE. THE HILO
SOUNDING...HOWEVER...REMAINS VERY COLD ALOFT WITH A 500 MB
TEMPERATURE OF -14 DEGREES C WITH A LIFTED INDEX OF -7. THE
WEATHER FORECAST TODAY REFLECTS THIS SCENARIO WITH A SLIGHT CHANCE
OF THUNDERSTORMS OVER OAHU AND MAUI COUNTY IN THE MORNING...AND
UPSLOPE BIG ISLAND THUNDERSTORMS EXPECTED IN THE AFTERNOON. WITH
THE UPPER LOW MOVING AWAY...THE FLASH FLOOD WATCH HAS BEEN
CANCELLED.

OVER THE BIG ISLAND...SHOWERS WITHIN LAYERED MID AND HIGH CLOUDS
ARE STREAMING UP FROM THE SOUTH. THE BIG ISLAND SUMMITS CAN EXPECT
RAIN AND SNOW INTO THE MORNING AND THE WINTER WEATHER ADVISORY
REMAINS IN EFFECT.

THE UPPER LOW IS EXPECTED TO MOVE EAST OF THE ISLANDS TODAY AND
TONIGHT...AS WARMER AIR MOVES IN FROM THE WEST. HOWEVER...THE
PARENT UPPER LEVEL TROUGH REMAINS IN THE ISLANDS/ VICINITY. THIS
WILL KEEP THE TEMPS ALOFT BELOW NORMAL...ALLOWING FOR WETTER THAN
NORMAL SHOWERS THROUGH THE WEEK. BY WEDNESDAY...MODEL GUIDANCE
DEPICTS ANOTHER MID-LEVEL LOW DEVELOPING NEAR THE ISLANDS...AND
ALTHOUGH MID-LEVEL TEMPS ARE NOT FORECAST TO BE AS COLD AS THEY
ARE WITH THE CURRENT LOW...RELATIVELY UNSETTLED WEATHER WILL
PREVAIL INTO NEXT WEEKEND.

NEAR THE SURFACE...A SURFACE TROUGH TO THE NW WILL MAINTAIN A WEAK
PRESSURE GRADIENT OVER THE STATE...MAINTAINING LIGHTER WINDS...AND
TURNING THE GENERAL FLOW OUT OF THE SOUTHEAST. LIGHT SOUTHEAST
TRADES OVER OAHU AND KAUAI WILL ALLOW FOR WIDESPREAD AFTERNOON SEA
AND NIGHTTIME LAND BREEZES THROUGH TUESDAY. FARTHER AWAY FROM THE
SURFACE TROUGH... OVER MAUI COUNTY AND THE BIG ISLAND...TRADES WILL
BE A BIT STRONGER. WITH THE LIGHT TO MODERATE E-SE WINDS ON THE
LARGE SCALE...CLOUDS AND SHOWERS WILL FAVOR WINDWARD AND MAUKA AREAS
DURING NIGHTS AND MORNINGS...SHIFTING TO LEEWARD AND INTERIOR AREAS
DURING AFTERNOONS AND EVENINGS...IN RESPONSE TO SEA BREEZE
CONVERGENCE. WHILE WIDESPREAD HEAVY RAIN IS NOT EXPECTED IN THIS
REGIME...THE LINGERING MODERATE INSTABILITY COULD HELP TO FUEL
ISOLATED POCKETS OF HEAVY RAIN...AND A SLIGHT CHANCE OF
THUNDERSTORMS OVER THE BIG ISLAND SLOPES. FOR THE REST OF THE
WEEK...BUILDING HIGH PRESSURE WILL INCREASE TRADES TO MODERATE/FRESH
LEVELS.

&&

.AVIATION...
THE LOW ALOFT OVER THE AREA WILL MAINTAIN UNSTABLE ATMOSPHERIC
CONDITIONS EAST OF KAUAI TODAY. AS A RESULT...DEEP CONVECTIVE
CLOUDS MAY PRODUCE ENOUGH LOW CEILINGS AT TIMES TO REQUIRE AIRMETS
FOR MOUNTAIN OBSCURATION. A CONVECTIVE SIGMET FOR EMBEDDED
THUNDERSTORMS HAS BEEN IN PLACE ACROSS MOST ISLANDS EAST OF KAUAI
SINCE SATURDAY EVENING. THE THREAT OF THUNDERSTORMS WILL FINALLY
DIMINISH EARLY THIS WEEK AS THE LOW WEAKENS AND MOVES OFF TO THE
EAST NORTHEAST.

&&

.MARINE...
LONG PERIOD SOUTH SWELLS WILL BUILD TODAY... BRINGING SURF HEIGHTS
TO ADVISORY LEVELS OF AT LEAST 8 FEET ALONG SOUTH FACING SHORES.
THIS SURF WILL CONTINUE INTO MONDAY BEFORE DIMINISHING...BUT ANOTHER
SOUTH SWELL EXPECTED BY MIDWEEK WILL PUSH SURF TO NEAR ADVISORY
LEVELS ONCE AGAIN. A LATE SEASON WEST NORTHWEST SWELL WILL PRODUCE A
NOTICEABLE BUMP IN SURF HEIGHTS ALONG NORTH AND WEST FACING SHORES
TODAY BEFORE DIMINISHING MONDAY.

&&

.HYDROLOGY...
SATURDAY EVENING...WATER LEVELS AT KAHANA STREAM AND WAIHEE
STREAM ROSE ABOVE THE PREVIOUS RECORDS TO 10.1 AND 9.4
FEET...RESPECTIVELY. THE PREVIOUS RECORD LEVELS WERE 9.4 FT AT
KAHANA AND 8.0 FT AT WAIHEE.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY FROM 6 AM THIS MORNING TO 6 PM HST MONDAY FOR
NIIHAU-KAUAI WINDWARD-KAUAI LEEWARD-OAHU SOUTH SHORE-WAIANAE
COAST-MOLOKAI LEEWARD-LANAI MAKAI-KAHOOLAWE-MAUI LEEWARD WEST-
MAUI CENTRAL VALLEY-LEEWARD HALEAKALA-KONA-SOUTH BIG ISLAND-BIG
ISLAND NORTH AND EAST.

WINTER WEATHER ADVISORY UNTIL NOON HST TODAY FOR BIG ISLAND
SUMMITS.

&&

MORRISON
AVIATION...HOUSTON