High Surf in Hawaii, May 21, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST SUN MAY 21 2006

.SYNOPSIS...
STRONG HIGH PRESSURE FAR NORTH OF THE ISLANDS WILL MAINTAIN BREEZY
TRADE WINDS THROUGH TODAY. AN AREA OF CLOUDS AND SHOWERS WILL CLEAR
KAUAI AND OAHU THIS MORNING...BUT WILL KEEP WINDWARD MAUI AND BIG
ISLAND SHOWERY TODAY. AFTER THE PASSAGE OF THIS CLOUD BAND...MOST
AREAS...EXCEPT WINDWARD BIG ISLAND...WILL SEE MINIMAL RAINFALL FOR
THE NEXT SEVERAL DAYS. LIGHTER TRADES ON MONDAY AND TUESDAY WILL
GIVE WAY TO LIGHT SOUTHEAST WINDS ON WEDNESDAY AND THURSDAY. THESE
LIGHT WINDS WILL CONTINUE INTO NEXT WEEKEND...WITH RELATIVELY DRY
WEATHER PREVAILING.

&&

.DISCUSSION...
CURRENTLY...A 1035 MB HIGH IS CENTERED ABOUT 1100 MILES NORTH OF
THE ISLANDS NEAR 38N 161W...AND IS SUPPLYING THE ISLANDS WITH PLENTY
OF NATURAL AIR CONDITIONING IN THE FORM OF STRONG TRADE WINDS.
WITHIN THE TRADE FLOW IS A NEARLY WEST TO EAST ORIENTED...100 MILE
WIDE...BAND OF BROKEN TO OVERCAST SHOWERY LOW CLOUDS THAT HAS BEEN
AFFECTING THE SMALLER ISLANDS OVERNIGHT. THE CLOUD BAND IS CURRENTLY
CLEARING KAUAI..OAHU AND MOLOKAI...BUT APPEARS SLATED TO KEEP
WINDWARD PORTIONS OF MAUI AND THE BIG ISLANDS SHOWERY INTO THIS
AFTERNOON AT LEAST. FURTHER NORTH AND EAST OF THIS BAND...THE CLOUD
FIELD IS DOMINATED BY BROKEN TO OVERCAST STRATOCUMULUS...WHICH
APPEAR TO CONTAIN LITTLE IN THE WAY OF PRECIPITATION.

AFTER THE PASSAGE OF THE SHOWERY CLOUD BAND...THE STABLE CLOUD FIELD
NORTHEAST OF THE ISLANDS WILL MOVE IN...AND ALTHOUGH WINDWARD AREAS
WILL BE ESPECIALLY CLOUDY NIGHTS AND MORNINGS...PRECIP AMOUNTS
SHOULD BE MINIMAL. THIS STABLE CLOUD FIELD WILL UNDERGO DIURNAL
CYCLES...BECOMING BROKEN TO OVERCAST IN THE OVERNIGHT HOURS...AND
SCATTERED TO BROKEN DURING THE DAYLIGHT HOURS.

LATEST GUIDANCE INDICATES A SURFACE RIDGE WILL MOVE TOWARD...AND
EVENTUALLY OVER...THE ISLANDS FROM THE NORTH AS THE HIGH TO OUR
NORTH WEAKENS TO 1022 MB ON MONDAY...AND THEN MOVES EAST ON TUESDAY.
OUR CURRENT BREEZY TRADES WILL WEAKEN ON MONDAY...WITH LIGHT EAST
WINDS TUESDAY AND WEDNESDAY. THE RIDGE IS FORECAST TO MOVE OVER THE
ISLANDS BY THURSDAY...AND REMAIN THERE INTO THE WEEKEND. THIS WILL
RESULT IN LIGHT SOUTHEAST TO SOUTH WINDS NEAR KAUAI...AND LIGHT TO
MODERATE EAST WINDS NEAR THE BIG ISLAND. ALTHO WEAK TROUGHING ALOFT
IS FORECAST TO BE IN PLACE AT THE TIME...IT IS NOT EXPECTED TO LEAD
TO MUCH DESTABILIZATION OF THE ATMOSPHERE. WITH THE LIGHT WINDS FROM
TUESDAY ONWARD...WE CAN EXPECT AFTERNOON INTERIOR AND LEEWARD CLOUDS
THAT DROP A FEW SHOWERS...BUT RAINFALL AMOUNTS ARE NOT EXPECTED TO
BE ALL THAT LARGE. THE LIGHT EAST TO SOUTHEAST SYNOPTIC FLOW WILL BE
OVERRIDDEN BY ISLAND SCALE EFFECTS...WITH EARLY MORNING LAND BREEZES
AND AFTERNOON SEA BREEZES...BUT MAY BE STRONG ENOUGH TO PROVIDE A
FEW WINDWARD SHOWERS WHEN ISLAND SCALE EFFECTS ARE LEAST
PRONOUNCED.

A RETURN TO A MORE TYPICAL TRADE WIND DIRECTION...WIND SPEED AND
WEATHER PATTERN IS EXPECTED AROUND NEXT SUNDAY.

&&

.MARINE...
A SMALL CRAFT ADVISORY /SCA/ WILL REMAIN IN EFFECT THRU THIS EVENING
FOR ALL COASTAL AND CHANNEL WATERS...AS OVERNIGHT WIND OBS SUPPORT A
CONTINUANCE FOR THE COASTAL WATERS. A SOUTH SWELL NEAR 3 FEET WITH A
PRIMARY PERIOD NEAR 15 SECONDS IS EXPECTED TO BUILD TODAY...AND
PEAK ON MONDAY. SIGNIFICANT WAVE HEIGHTS WILL BE BELOW 8 FEET...BUT
SETS NEAR THE 8 FOOT ADVISORY THRESHOLD ARE LIKELY AT LOCATIONS WITH
THE GREATEST SHOALING/EXPOSURE ON MONDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY FOR ALL COASTAL WATERS/CHANNELS TIL 6 PM
TODAY...EXCEPT PAILOLO AND ALENUIHAHA CHANNELS AND BIG ISLAND SE
WATERS TIL 6AM MONDAY.

&&

BIRCHARD