High Surf in Hawaii, March 11 to 14, 2016

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST FRI MAR 11 2016

.SYNOPSIS...
COOL AND BREEZY TRADE WIND WEATHER WILL CONTINUE THROUGH THE WEEKEND
AS STRONG SURFACE HIGH PRESSURE REMAINS NORTH OF THE STATE. THE
TRADE WINDS WILL BRING PERIODS OF CLOUDS AND A FEW SHOWERS TO
WINDWARD AREAS...ESPECIALLY DURING NIGHTS AND MORNINGS. INCREASED
MOISTURE APPROACHING THE ISLANDS FROM THE SOUTHEAST MAY FUEL
ADDITIONAL WINDWARD SHOWERS ON THE BIG ISLAND AND MAUI THIS WEEKEND.
TRADE WINDS WILL DIMINISH TO MODERATE SPEEDS ON SUNDAY...BECOMING
LIGHT AND VARIABLE MONDAY NIGHT INTO TUESDAY. A COLD FRONT IS
EXPECTED TO MOVE DOWN THE ISLAND CHAIN ON TUESDAY...BRINGING A
BRIEF PERIOD OF SHOWERS...FOLLOWED BY ANOTHER ROUND OF COOL AND
BREEZY WEATHER.

&&

.DISCUSSION...
A STRONG RIDGE OF HIGH PRESSURE CENTERED ALONG 30N WILL MAINTAIN
BREEZY TRADE WINDS THROUGH SATURDAY. WINDS WILL GRADUALLY EASE AND
VEER TO THE ESE SUNDAY THROUGH MONDAY AS THE HIGH WEAKENS AND MOVES
FAR NE OF THE AREA. A LOW WILL RAPIDLY DEVELOP WELL N OF THE ISLANDS
MONDAY NIGHT AND TUESDAY...AND WINDS LOCALLY WILL WEAKEN TO THE
POINT THAT THEY BRIEFLY BECOME WEAK AND VARIABLE. A FRONT ASSOCIATED
WITH THE LOW IS EXPECTED TO MOVE DOWN THE ISLAND CHAIN ON TUESDAY
INTO WEDNESDAY. AS THE LOW PULLS AWAY TO THE NE...BREEZY AND COOL
N WINDS WILL GRADUALLY VEER TO THE NE DURING THE SECOND HALF OF
NEXT WEEK.

A WIND ADVISORY IS IN EFFECT FOR LANAI AND KAHOOLAWE AND PORTIONS
OF THE BIG ISLAND THROUGH TODAY. WITH WINDS NOT EXPECTED TO CHANGE
MUCH THROUGH SATURDAY...WILL MONITOR OBSERVATIONS TODAY TO DETERMINE
IF AN EXTENSION IN TIME IS REQUIRED.

AN OVERNIGHT UPTICK IN SHOWERS APPEARS TO BE RELATED TO THE PASSAGE
OF A WEAK BACKDOOR FRONTAL BOUNDARY...THAT IS STILL FUELING WINDWARD
SHOWERS THIS MORNING. AS THIS MOISTURE AXIS SLIDES W OF THE
ISLANDS...CLOSED-CELL STABLE STRATOCUMULUS PREVAILING UPSTREAM OF
THE ISLANDS ARE EXPECTED TO MOVE IN LATER TODAY...AND TRADE SHOWERS
SHOULD DIMINISH AND REMAIN BELOW NORMAL THROUGH SATURDAY. THE ISLAND
AIR MASS WILL GRADUALLY MOISTEN AND WARM OVER THE NEXT SEVERAL DAYS
WITH DEW POINTS CLIMBING OUT OF THE UPPER 50/S...AND INTO THE LOW TO
MID-60S. LATEST MODEL GUIDANCE INDICATES THAT MOISTURE POOLED SE OF
THE BIG ISLAND WILL TRACK WNW OVER WINDWARD BIG ISLAND...AND
POTENTIALLY THE OTHER ISLANDS...TO FUEL INCREASED TRADE WIND SHOWERS
ON SUNDAY. ANOTHER AREA OF MOISTURE MAY MOVE OVER E AND SE PORTIONS
OF THE BIG ISLAND AND MAUI IN THE SE FLOW THAT DEVELOPS MONDAY NIGHT
THROUGH TUESDAY NIGHT. THE FRONTAL PASSAGE NEXT WEEK DOES NOT
APPEAR TO BE A HEAVY RAIN THREAT...AND ACTUALLY LOOKS TO BRING
MINIMAL RAINFALL TOTALS.

&&

.AVIATION...
A STRONG SFC HIGH FAR NW OF THE AREA WILL PRODUCE STRONG NE WINDS
THROUGH TODAY. AIRMET TANGO WILL REMAIN UP THROUGH TODAY FOR TEMPO
MOD TURB BLW 080 SW OF THE MTN OF ALL THE ISLANDS AND FOR STG SFC
WIND OVER WATERS AROUND THE BIG ISLAND AND MAUI.

VFR COND WILL PREVAIL...BUT STABLE LOW CLOUDS MAY PRODUCE LOCALIZED
MVFR CEILINGS ALONG NE SECTIONS OF THE ISLANDS.

&&

.MARINE...
TRADE WINDS ARE SUFFICIENTLY STRONG TO PRODUCE GALE FORCE
WINDS IN AREAS WHERE THE WINDS ARE MOST STRONGLY ACCELERATED BY THE
TERRAIN OF THE BIG ISLAND...WITH A SMALL CRAFT ADVISORY /SCA/ IN
EFFECT FOR ALL OTHER MARINE ZONES. LITTLE SIGNIFICANT CHANGE IN WIND
SPEED IS EXPECTED THROUGH SATURDAY NIGHT...SO THE GALE WARNING/SCA
WILL LIKELY NEED TO BE EXTENDED IN TIME. WIND SPEEDS ON SUNDAY WILL
LIKELY DROP BELOW SCA THRESHOLDS...BUT LINGERING WIND WAVES AND AN
INCREASING LONG-PERIOD NNW SWELL WILL DRIVE SEAS ABOVE THE 10 FOOT
THRESHOLD FOR AN SCA IN MANY MARINE ZONES FROM SATURDAY NIGHT
THROUGH SUNDAY.

NEAR SHORE BUOYS IN WINDWARD WATERS SHOW A SPIKE IN COMBINED SEAS
OVER THE PAST COUPLE OF HOURS...AND CURRENTLY RANGE FROM 9 TO 12
FEET. THESE OBSERVATIONS ARE SEVERAL FEET HIGHER THAN WAVE WATCH
GUIDANCE...DUE TO A COMBINATION OF SHORT-PERIOD WIND WAVES FROM THE
E...AND A RECENT INCREASE IN A SLIGHTLY LONGER PERIOD NNW SWELL. THE
WIND WAVES ARE LARGE ENOUGH TO WARRANT A HIGH SURF ADVISORY FOR E
FACING SHORES OF MOST ISLANDS...WHICH IS IN EFFECT THROUGH TONIGHT.

THE CURRENT NNW SWELL IS NOT LARGE ENOUGH TO WARRANT ANY HEADLINES
ALTHOUGH THE COMBINATION OF WINDS AND SWELL IS MAKING FOR RELATIVELY
ROUGH CONDITIONS ALONG MANY N FACING SHORES. THIS SWELL WILL
GRADUALLY DIMINISH INTO SATURDAY...BUT AN INCREASING LONGER PERIOD
NNW SWELL BUILDING SATURDAY AND PEAKING SUNDAY WILL PRODUCE ADVISORY
LEVEL SURF ALONG N FACING SHORES...AND MAY HAVE ENOUGH OF A N
COMPONENT TO PRODUCE LIGHT TO MODERATE SURGES IN KAHULUI AND HILO
HARBORS. LONG RANGE MODELS INDICATE STRONG CYCLOGENESIS DUE N OF THE
ISLANDS AROUND THE MIDDLE OF NEXT WEEK. IF THIS WERE TO OCCUR AS
FORECAST...SURF WOULD BE PUSHED TO WARNING LEVELS ALONG N FACING
SHORES...AND WOULD POSE A MORE SIGNIFICANT SURGE THREAT IN THE
HARBORS.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 AM HST SATURDAY FOR EAST FACING
SHORES OF KAUAI OAHU MOLOKAI MAUI KAHOOLAWE AND THE BIG ISLAND.

WIND ADVISORY UNTIL 6 PM HST THIS EVENING FOR LANAI-KAHOOLAWE-
SOUTH BIG ISLAND-BIG ISLAND NORTH AND EAST-KOHALA.

GALE WARNING UNTIL 6 PM HST THIS EVENING FOR ALENUIHAHA CHANNEL-
BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS.

SMALL CRAFT ADVISORY UNTIL 6 AM HST SATURDAY FOR KAUAI NORTHWEST
WATERS-KAUAI WINDWARD WATERS-KAUAI LEEWARD WATERS-KAUAI CHANNEL-
OAHU WINDWARD WATERS-OAHU LEEWARD WATERS-KAIWI CHANNEL-MAUI
COUNTY WINDWARD WATERS-MAUI COUNTY LEEWARD WATERS-MAALAEA BAY-
PAILOLO CHANNEL-BIG ISLAND WINDWARD WATERS.

&&

DISCUSSION/MARINE...BIRCHARD
AVIATION...FOSTER