Drought in Hawaii, April 1 to 30, 2016

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST THU MAR 31 2016

.SYNOPSIS...
TRADE WINDS WILL GRADUALLY STRENGTHEN FRIDAY THROUGH THE REST OF THE
WEEKEND AS A SURFACE HIGH PASSES FAR NORTH OF THE ISLANDS. THE
MODERATE TRADE WINDS WILL DELIVER A FEW WINDWARD SHOWERS MAINLY
DURING NIGHTS AND MORNINGS. WINDS ARE EXPECTED TO WEAKEN MONDAY AS
ANOTHER FRONT APPROACHES THE STATE FROM THE NORTHWEST. BREEZY TRADE
WINDS ARE EXPECTED TO RETURN ACROSS THE AREA BEHIND THE FRONT.

&&

.DISCUSSION...
FAIR WEATHER CONTINUES ACROSS THE ISLANDS THIS EVENING AS A RATHER
DRY AND STABLE AIRMASS PERSISTS IN THE AREA. A WEAK SURFACE RIDGE IS
ALSO LOCATED JUST NORTH OF THE STATE...RESULTING IN LIGHT WINDS
OVER THE AREA. THERE ARE STILL SOME LINGERING LOW CLOUDS FROM THE
AFTERNOON CONVECTION...THOUGH THESE WILL DISSIPATE IN THE COMING
HOURS. WINDS WILL BE LIGHT ENOUGH TO ALLOW LAND BREEZES TO DEVELOP
OVERNIGHT.

THE WEAK SURFACE RIDGE IS STILL EXPECTED TO NUDGE NORTH ON
FRIDAY...WITH A SURFACE HIGH PASSING NORTH OF THE STATE LATE FRIDAY
AND SATURDAY. THIS WILL LEAD TO A SLOW STRENGTHENING TRADE WINDS
ACROSS THE ISLANDS OVER THE WEEKEND. WITH THE RETURN OF THE STRONGER
TRADE WINDS...LOW CLOUDS AND SHOWERS CARRIED BY THE WINDS TO AFFECT
MAINLY WINDWARD AND MOUNTAIN AREAS. FORECAST MODELS INDICATE AIRMASS
IN THE ISLAND VICINITY WILL REMAIN STABLE AND SOMEWHAT DRY. THUS
PRECIPITATION AMOUNTS WILL ATTENUATED.

WINDS WILL WEAKEN AND VEER SOUTHEAST ON MONDAY OVER THE ISLANDS IN
ADVANCE OF ANOTHER APPROACHING FRONT FROM THE NORTHWEST...WITH
POSSIBLY MORE WIDESPREAD VOLCANO EMISSIONS ACROSS THE AREA. LATEST
FORECAST MODELS STILL HAVE A SLIGHT DIFFERENCE IN TERMS OF HOW FAST
THIS PENDING FRONTAL SYSTEM WILL REACH THE ISLANDS...WITH GFS STILL
THE FASTEST WHILE ECMWF IS SLIGHTLY SLOWER. AT LEAST THESE MODELS
ARE CLOSE ENOUGH SUCH THAT CONFIDENCE IS HIGHER ON THIS FRONT
REACHING KAUAI BY TUESDAY MORNING...THEN ADVANCING DOWN THE ISLAND
CHAIN THROUGH REST OF TUESDAY INTO WEDNESDAY. ONCE AGAIN...THIS WILL
BE ANOTHER WEAK FRONT...WITH THE CLOUD BAND ASSOCIATED WITH THE
FRONT BRINGING SOME SHOWERS. A STRONG HIGH PRESSURE BEHIND THE FRONT
WILL PROVIDE RATHER STRONG NORTH TO NORTHEAST WINDS TO THE STATE.
MOISTURE EMBEDDED IN THE WIND FLOW WILL AFFECT MAINLY WINDWARD AND
MOUNTAIN AREAS...THOUGH WINDS MAY BE STRONG ENOUGH TO CARRY SOME OF
THE LOW CLOUDS AND SHOWERS TO LEE AREAS OF THE SMALLER ISLANDS.

&&

.AVIATION...
RETURNING LIGHT TRADES WILL KEEP SOME CLOUDS FOCUSED ACROSS WINDWARD
SECTIONS...BUT WILL STILL BE LIGHT ENOUGH FOR OFFSHORE LAND BREEZES
TO DEVELOP ACROSS SOME AREAS AGAIN OVERNIGHT. AFTERNOON CLOUDS THAT
FORMED ACROSS INTERIOR AND LEEWARD SECTIONS WILL CLEAR OUT DURING
THE EVENING.  EXPECT VFR CONDITIONS TO PREVAIL OVERNIGHT...WITH
ISOLATED MVFR POSSIBLE AT TIMES ACROSS WINDWARD AREAS. TRADE WINDS
WILL INCREASE ON FRIDAY AND FRIDAY NIGHT...WITH AIRMET TANGO FOR
MODERATE LOW LEVEL TURB OVER AND DOWNWIND OF THE HIGHER TERRAIN
POSSIBLY NEEDED BY FRIDAY EVENING.

NO AIRMETS ARE CURRENTLY IN EFFECT AND NONE ARE ANTICIPATED
OVERNIGHT.

&&

.MARINE...
THE CURRENT WEST NORTHWEST SWELL CONTINUES TO SLOWLY DECLINE THIS
EVENING...THOUGH SURF HEIGHTS WILL STILL BE LARGE ENOUGH ALONG NORTH
AND WEST FACING SHORES OF THE SMALLER ISLANDS AS WELL AS WEST
FACING SHORES OF THE BIG ISLAND TO WARRANT THE CONTINUATION OF THE
HIGH SURF ADVISORY AT TIME. STILL EXPECT THE SWELL TO SUBSIDE ENOUGH
BY EARLY FRIDAY MORNING SUCH THAT SURF WILL BE BELOW ADVISORY LEVELS
ALONG THE AFFECTED SHORES...THEREFORE ALLOWING THE CANCELLATION OF
THE ADVISORY.

STRENGTHENING TRADE WINDS OVER THE WEEKEND MAY BRING ADVISORY LEVEL
WINDS TO THE USUAL WINDIER COASTAL MARINE ZONES AROUND MAUI AND THE
BIG ISLAND BEGINNING FRIDAY EVENING AND CONTINUING THROUGH THE REST
OF THE WEEKEND. AS THE WINDS ARE EXPECTED TO DIMINISH ON
MONDAY...CONDITIONS WILL IMPROVE. BUT THEN STRONGER WINDS ARE
EXPECTED TO RETURN BY THE MIDDLE OF NEXT WEEK...WHICH MAY RESULT IN
THE POSTING OF SMALL CRAFT ADVISORY FOR MUCH OF THE COASTAL WATERS.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 AM HST FRIDAY FOR NORTH AND WEST FACING
SHORES OF KAUAI NIIHAU OAHU AND MOLOKAI...NORTH FACING SHORES OF
MAUI...AND FOR WEST FACING SHORES OF THE BIG ISLAND.

&&

DISCUSSION/MARINE...HUI
AVIATION...JACOBSON