High Surf in Hawaii, April 7, 2008

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST MON APR 7 2008

.SYNOPSIS...
A LOW NORTHEAST OF THE ISLANDS WILL MAINTAIN COOL...NORTHEAST WINDS
OVER THE ISLANDS TODAY...WITH WINDS EASING OVER THE BIG ISLAND
DURING THE AFTERNOON. THE LOW WILL WEAKEN INTO A TROUGH AND MOVE
ACROSS THE ISLANDS TONIGHT THROUGH WEDNESDAY...ENHANCING SHOWERS AND
CAUSING WINDS TO SHIFT OUT OF THE EAST AND SOUTHEAST. TRADE WINDS
WILL RETURN LATER IN THE WORK WEEK ALTHOUGH THE ATMOSPHERE WILL
REMAIN SOMEWHAT UNSTABLE WITH PERIODS OF THICK HIGH CLOUDS.

&&

.DISCUSSION...
ONE LAST DAY OF SOMEWHAT COOL...NORTHEASTERLY WINDS ARE IN STORE
AS A WEAKENING SURFACE LOW AND ASSOCIATED UPPER LOW 400 MILES
NORTHEAST OF HILO APPROACH THE STATE. THIS FLOW IS GENERALLY STABLE
WITH LIMITED MOISTURE...BUT SMALL BANDS OF SHOWERS PEELING OFF THE
LOW HAVE BEEN IMPACTING THE ISLANDS. ONE SUCH BAND DROPPED GENERALLY
LESS THAN 1/4 OF AN INCH ACROSS WINDWARD BIG ISLAND AND MAUI
OVERNIGHT...AND ANOTHER POORLY ORGANIZED BAND MOVING ONTO WINDWARD
AREAS NOW WILL CLEAR THE STATE AROUND SUNRISE. AS THE SURFACE LOW
MOVES CLOSER...WINDS WILL GRADUALLY EASE TODAY...ESPECIALLY ACROSS
THE EASTERN END OF THE STATE. ON THE BIG ISLAND...WINDS WILL BE
LIGHTEST...AND AFTERNOON SEA BREEZES WILL BECOME DOMINANT...CAUSING
THE WIND FLOW IN THE VICINITY OF KILAUEA TO STAGNATE.

THE SURFACE LOW WILL WEAKEN INTO A TROUGH AS IT PASS OVER THE
ISLAND CHAIN FROM EAST TO WEST TONIGHT INTO WEDNESDAY. WINDS WILL
SHIFT OUT OF THE EAST AND SOUTHEAST AFTER THE TROUGH PASSES THROUGH.
DURING THIS TIME THE ASSOCIATED UPPER LOW WILL PASS NORTH OF THE
STATE...DESTABILIZING THE ATMOSPHERE AND ENHANCING SHOWERS. WINDWARD
POPS WERE BUMPED UP SLIGHTLY AS THE TROUGH MOVES THROUGH...BUT WITH
FORECAST MODELS KEEPING THE GREATEST INSTABILITY AND MOISTURE NORTH
OF THE ISLANDS...HEAVY SHOWERS HAVE BEEN LEFT OUT OF THE FORECAST
FOR NOW.

THE GFS...ECMWF...AND NOGAPS MAINTAIN SOMEWHAT UNSTABLE CONDITIONS
AND A BUILDING TRADE WIND FLOW DURING THE SECOND HALF OF THE WORK
WEEK. THE SURFACE TROUGH AND UPPER LOW WILL SLOWLY MOVE WEST OF
KAUAI ON WEDNESDAY...ALLOWING WINDS TO TREND MORE EASTERLY. THE
UPPER LOW WILL STALL AND OPEN INTO A TROUGH ALONG 165W...CLOSE
ENOUGH TO KEEP THE ATMOSPHERE MODESTLY UNSTABLE AND MAINTAIN THE
THREAT OF ENHANCED SHOWERS. THE UPPER TROUGH WILL ALSO DRAW A
SHIELD OF HIGH CLOUDS OVER THE STATE.

FORECAST MODELS BEGIN TO DIVERGE HEADING INTO NEXT WEEKEND. AN UPPER
TROUGH IN THE JET STREAM WILL DIP INTO THE CENTRAL PACIFIC...PICKING
UP THE UPPER TROUGH WEST OF KAUAI. HOWEVER...THE MODELS DIFFER ON
HOW QUICKLY THE UPPER TROUGH WILL LIFT NORTH OF THE AREA. WHEN IT
DOES...A BUILDING SURFACE HIGH NORTHWEST OF THE STATE WILL BRING
INCREASED TRADE WINDS. THE GFS BRINGS IN THE STRONGER TRADE WINDS BY
FRIDAY...WITH THE NOGAPS AND ECMWF LAGGING BY A DAY.

&&

.MARINE...
A FETCH STRONGER NORTHEAST WINDS ASSOCIATED WITH THE SURFACE LOW
SEVERAL HUNDRED MILES NORTHEAST OF THE STATE IS PRODUCING BORDERLINE
CONDITIONS ACROSS HAWAIIAN WATERS. SEAS AT THE KAILUA BUOY HAVE BEEN
BOUNCING BETWEEN 9 AND 10 FEET OVERNIGHT. WITH THE LOW WEAKENING THE
WAVE WATCH III MODEL SHOWS A DECLINE IN THE SEAS TODAY...AND WE HAVE
DECIDED TO HOLD OFF ON A SMALL CRAFT ADVISORY. HOWEVER...THE
INCREASE HAS LIKELY CAUSED SURF ALONG EAST FACING SHORES TO RISE
AROUND THE 8 FOOT ADVISORY LEVEL. SURF WILL SUBSIDE THIS AFTERNOON.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY FOR EAST FACING SHORES OF KAUAI OAHU MOLOKAI MAUI
AND THE BIG ISLAND THROUGH THIS AFTERNOON.

&&

WROE