High Surf in Hawaii, March 5 to 6, 2016

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
331 AM HST SAT MAR 5 2016

.SYNOPSIS...
LIGHT TRADE WINDS HAVE RETURNED ACROSS THE ISLANDS THIS WEEKEND
AS A RIDGE OF HIGH PRESSURE RETREATS NORTHWARD. HOWEVER...WINDS
WILL BEGIN TO SWING BACK TO SOUTHERLIES LATE SUNDAY AS A FRONT
APPROACHES THE STATE FROM THE NORTHWEST. THE FRONT WILL MOVE
THROUGH THE ISLANDS TUESDAY AND WEDNESDAY...BRINGING A GOOD CHANCE
OF SHOWERS ALONG WITH WINDY CONDITIONS THROUGH LATE NEXT WEEK.

&&

.DISCUSSION...
A WEAK SURFACE RIDGE WHICH SPANNED THE ISLANDS OVER THE LAST DAY
OR SO HAS BEGUN TO RETREAT NORTHWARD...ALLOWING OUR LOCAL PRESSURE
GRADIENT TO STEEPEN SUFFICIENTLY TO SUPPORT LIGHT EAST TO
NORTHEAST TRADE WINDS. AS TRADES RETURN...SHALLOW MOISTURE NOW
POOLED NEAR MAUI AND THE BIG ISLAND WILL GRADUALLY BUILD BACK
TOWARD THE WEST...RESTORING A PATTERN OF CLOUDS AND SHOWERS
FAVORING WINDWARD AND MAUKA SECTIONS OF ALL THE ISLANDS.
OVERALL...WE EXPECT RATHER STABLE CONDITIONS THROUGH THE WEEKEND
AND INTO EARLY NEXT WEEK...WITH ONLY LIGHT RAINFALL AMOUNTS
EXPECTED.

BY SUNDAY NIGHT...WINDS WILL BEGIN TO VEER TO SOUTHERLIES AS A
FRONT APPROACHES THE ALOHA STATE FROM THE NORTHWEST. MODELS SHOW
THIS FRONT WILL REACH KAUAI SOMETIME TUESDAY...THEN CONTINUE TO
MOVE SOUTHEASTWARD ACROSS THE ISLAND CHAIN THROUGH WEDNESDAY. THE
FRONT SHOULD THEN PASS EAST OF THE ISLANDS LATE WEDNESDAY. A BAND
OF CLOUDS AND SHOWERS WILL ACCOMPANY THE FRONT...INTRODUCING A
SHORT-LIVED BOUT OF INCREASED RAINFALL FOR EACH ISLAND IN TURN AS
THE FRONT PASSES BY. WE EXPECT STRONG NORTH TO NORTHEAST WINDS IN
THE WAKE OF THIS FRONT...LASTING THROUGH THURSDAY AND INTO FRIDAY.
THESE WINDS WILL THEN WEAKEN SLIGHTLY AND VEER BACK TO EAST TO
NORTHEAST TRADES AS HIGH PRESSURE BEHIND THE FRONT SETTLES IN TO
OUR NORTH.

&&

.AVIATION...
THE AREA OF LOW CLOUDS AND SHOWERS OVER PORTIONS OF THE WINDWARD BIG
ISLAND CONTINUES TO DIMINISH EARLY THIS MORNING. THEREFORE...AIRMET
SIERRA FOR MTN OBSCURATION IS BEING DISCONTINUED. THERE ARE STILL
PATCHES OF LOW CLOUDS AND SHOWERS IN THE VICINITY OF UPOLU POINT AND
CAPE KUMAKAHI ON THE BIG ISLAND...AS WELL AS OVER PARTS OF EAST
MAUI. HOWEVER...THESE DO NOT APPEAR TO BE WIDESPREAD ENOUGH TO
REQUIRE AN AIRMET AT THIS TIME.

ELSEWHERE...LIGHT BACKGROUND WINDS ALLOWED DOWNSLOPE WINDS TO
DEVELOP ACROSS THE ISLANDS FROM KAUAI TO MOLOKAI AND LANAI. AS A
RESULT...VFR CONDITIONS PREVAIL ACROSS MOST OF THESE ISLANDS...IN
ADDITION TO LEEWARD MAUI AND THE BIG ISLAND.

A SURFACE HIGH PASSING BY NORTH OF THE ISLANDS LATER TODAY AND
TONIGHT IS EXPECTED TO PRODUCE LIGHT LOW LEVEL TRADE WIND FLOW OVER
MOST OF THE STATE. THE TRADE WINDS MAY CARRY ADDITIONAL LOW CLOUDS
AND LIGHT SHOWERS INTO THE WINDWARD SECTIONS OF THE BIG ISLAND AND
MAUI THROUGH THIS AFTERNOON. THERE MAY ALSO BE LOCAL SEA BREEZES
OVER SOME LEEWARD SECTIONS THIS AFTERNOON THAT MAY PRODUCE CLOUDS
AND A SHOWER OR TWO. OTHERWISE...VFR CONDITIONS WILL PREVAIL OVER
THE REMAINING AREAS OF THE STATE.

NOTE THAT THE VOLCANIC HAZE LAYER...WHICH WAS MOST NOTICEABLE ACROSS
THE SMALLER CENTRAL ISLANDS AND THE LEEWARD BIG ISLAND INTO FRIDAY
EVENING...APPEARS TO BE PUSHING SOUTHWARD AWAY FROM MAUI THIS
MORNING. SOME VOLCANIC HAZE MAY CONTINUE TO CAUSE LOCALIZED REDUCED
VISIBILITIES OVER PARTS OF THE LEEWARD BIG ISLAND THROUGH THIS
EVENING.

&&

.MARINE...
A LONG PERIOD NORTHWEST SWELL ARRIVING TODAY WILL PUSH SURF TO
HIGH-END ADVISORY...NEAR WARNING...LEVELS ACROSS NORTH AND WEST
FACING SHORES OF THE SMALLER ISLANDS TONIGHT THROUGH SUNDAY
NIGHT. ACROSS WEST FACING SHORES OF THE BIG ISLAND...THIS SAME
SWELL MAY RESULT IN SURF REACHING WARNING LEVELS FROM LATE
TONIGHT THROUGH SUNDAY.

WINDS WILL REMAIN BELOW SMALL CRAFT ADVISORY /SCA/ LEVELS THROUGH
EARLY NEXT WEEK. THE NEW NORTHWEST SWELL ARRIVING TODAY WILL
REQUIRE AN SCA FOR MOST HAWAIIAN WATERS STARTING LATE TODAY AND
CONTINUING THROUGH SUNDAY NIGHT. AN EXTENDED PERIOD OF STRONG
NORTHEAST WINDS AND ELEVATED SEAS REQUIRING A SCA FOR MOST WATERS
IS EXPECTED AFTER THE PASSAGE OF A FRONT THAT IS FORECAST TO MOVE
DOWN THE ISLAND CHAIN TUESDAY AND WEDNESDAY. A GALE WARNING MAY
ALSO BE NEEDED FOR THE TYPICALLY WINDIER AREAS AROUND MAUI COUNTY
AND THE BIG ISLAND.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY FROM NOON TODAY TO 6 PM HST SUNDAY FOR NIIHAU-
KAUAI WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-MAUI CENTRAL VALLEY-WINDWARD
HALEAKALA.

SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM HST SUNDAY FOR
KAUAI NORTHWEST WATERS-KAUAI WINDWARD WATERS-KAUAI LEEWARD
WATERS-KAUAI CHANNEL-OAHU WINDWARD WATERS-KAIWI CHANNEL-MAUI
COUNTY WINDWARD WATERS-ALENUIHAHA CHANNEL-BIG ISLAND WINDWARD
WATERS.

&&

PUBLIC/MARINE...POWELL
AVIATION...HOUSTON