744
FXHW60 PHFO 031342
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
342 AM HST FRI APR 3 2026
SYNOPSIS
MODERATE TRADE WINDS WILL PERSIST THROUGH THIS WEEKEND AND BRING
SCATTERED SHOWERS TO MAINLY WINDWARD AND MAUKA LOCATIONS. BY EARLY
NEXT WEEK, A TROUGH DEEPENING WEST OF THE ISLANDS WILL ACT TO
WEAKEN TRADE WIND FLOW. BY MID-WEEK, THIS TROUGH WILL APPROACH THE
ISLANDS AND BRING GUSTY SOUTHERLY WINDS AND ROUNDS OF MODERATE TO
HEAVY RAIN.
DISCUSSION
IR SATELLITE FROM THIS MORNING SHOWS A LAYER OF HIGH CLOUDS
ASSOCIATED WITH A SUB-TROPICAL JET STREAMING WEST TO EAST OVER
MOST ISLANDS, THICKEST BETWEEN MOLOKAI AND THE BIG ISLAND.
SCATTERED LOW CLOUDS AND EMBEDDED LIGHT SHOWERS, CAUGHT IN THE
TRADE FLOW, HAVE MANAGED TO SQUEEZE OUT A FEW HUNDREDTHS OF AN
INCH OF ACCUMULATION OVERNIGHT AT SEVERAL WINDWARD SITES ON EACH
ISLAND. THE 12Z RAOB SOUNDING AT HILO CLEARLY INDICATED A
BOUNDARY LAYER TEMPERATURE INVERSION AT AROUND 6000 FEET, A DRY
AND STABLE LAYER IN THE MID LEVELS, AND SHARP INCREASE OF MOISTURE
IN THE UPPER LEVELS (BASE OF HIGH CLOUDS) AT AROUND 25000 FEET.
LATEST GUIDANCE HAS THESE HIGH CLOUDS EXITING THE REGION BY
LATE TONIGHT.
A TRANSIENT SURFACE HIGH WELL NORTHEAST OF THE STATE IS PROGGED
MOVE EASTWARD BY THIS WEEKEND, BUT WILL BE REINFORCED BY YET
ANOTHER SURFACE HIGH BUILDING IN FROM THE NORTHWEST. ALL IN ALL,
THIS SHOULD KEEP MODERATE TRADE WINDS IN PLACE ACROSS THE REGION
FOR THE NEXT SEVERAL DAYS. LOW CLOUD COVER WITH EMBEDDED LIGHT
SHOWERS WILL CONTINUE TO FAVOR WINDWARD AND MAUKA SECTIONS OF THE
ISLANDS, ESPECIALLY DURING THE NIGHTS AND EARLY MORNINGS.
MONDAY INTO TUESDAY, A LARGE BROAD TROUGH BEGINS TO SAG
SOUTHWARD, WEST OF THE STATE. IN RESPONSE, BACKGROUND FLOW
WEAKENS AND SHIFTS EASTERLY, THEN SOUTHEASTERLY. A SLIGHT INCREASE
IN MOISTURE, ALONG AFTERNOON SEA BREEZE DEVELOPMENT, COULD SPARK
A FEW SHOWERS OVER ISLAND INTERIORS AND ON MOUNTAIN SLOPES.
TUESDAY NIGHT THROUGH LATE WEEK, A VERY UNSETTLED WEATHER PATTERN
APPEARS TO BE TAKING SHAPE. MODEL SOLUTIONS HAVE BEEN CONSISTENT
IN DEEPENING THE AFOREMENTIONED TROUGH WEST OF THE ISLANDS AND
EVENTUALLY INDUCING A SURFACE LOW AND ASSOCIATED FRONT. AHEAD OF
THESE FEATURES, DEEP LAYER SOUTH OR SOUTHWESTERLY FLOW WILL DRAW
TROPICAL MOISTURE NORTHWARD OVER THE STATE. SOUTHERLY WINDS MAY
BECOME GUSTY AT TIMES, ESPECIALLY ON THE LEE SIDES OF ANY TERRAIN.
VARIOUS LOBES OF ENERGY ROTATING AROUND THE TROUGH WILL ACT TO
DESTABILIZE THE ATMOSPHERE AND PROVIDE LIFT. ROUNDS OF HEAVIER
RAIN, UNFORTUNATELY, WILL BE POSSIBLE AND MAY LEAD TO MORE
FLOODING CONCERNS. HOWEVER, IT IS STILL TOO EARLY TO ACCURATELY
DETERMINE AMOUNTS AND WHICH ISLANDS WOULD BE MOST AFFECTED. PLEASE
KEEP YOURSELF UPDATED THROUGH THE WEEKEND FOR THE LATEST
FORECASTS.
AVIATION
MODERATE TRADE WINDS WILL PERSIST THROUGH THE 24 H PERIOD, WITH
BRIEF SHOWERS FAVORING WINDWARD AREAS OVERNIGHT THROUGH THE EARLY
MORNING PERIODS. THESE SHOWERS COULD BRING PERIODS OF MVFR
CIGS/VSBYS.
AIRMET TANGO REMAINS IN EFFECT ACROSS THE STATE FOR MODERATE
TURBULENCE BETWEEN FL280 AND FL380, WHICH WILL PERSIST THROUGH THE
DAY TODAY.
MARINE
MODERATE TO LOCALLY FRESH TRADE WINDS WILL REMAIN IN PLACE THROUGH
THE WEEKEND. WINDS WILL THEN BEGIN TO VEER EAST TO SOUTHEAST BY
MONDAY AHEAD OF A FRONT APPROACHING FROM THE NORTHWEST AND TROUGH
MOVING UP FROM THE SOUTHWEST. THIS SURFACE FRONT AND TROUGH WILL
BE DRIVEN BY AN UPPER LEVEL TROUGH, WHICH COULD ALLOW FOR ISOLATED
THUNDERSTORMS OVER THE OFFSHORE AND COASTAL WATERS THROUGH MUCH
OF NEXT WEEK. A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE
TYPICALLY WINDIER WATERS AROUND MAUI COUNTY AND THE BIG ISLAND
THROUGH TONIGHT.
SURF OVER NORTH AND EAST FACING SHORES WILL REMAIN CHOPPY TODAY
AS NORTHEAST SWELL DECREASES. BY TONIGHT THROUGH TOMORROW, SMALL,
MEDIUM-PERIOD WEST-NORTHWEST (310 DEGREE) ENERGY WILL FILL IN AND
BUMP UP SURF FOR NORTH AND WEST FACING SHORES. THEN BY MONDAY
NIGHT THROUGH WEDNESDAY, A MODERATE MEDIUM-PERIOD WEST-
NORTHWEST SWELL WILL FILL IN AND INCREASE SURF TO JUST BELOW
ADVISORY LEVELS.
ALONG SOUTH FACING SHORES, EXPECT SMALL REINFORCEMENTS TO
PROVIDE PERIODS OF SMALL SURF THROUGH THE WEEKEND UNTIL A LARGER
LONG PERIOD SOUTH SWELL FILLS IN MONDAY THROUGH MID WEEK.
STRENGTHENING SOUTHERLY WINDS MAY LEAD TO INCREASINGLY CHOPPY
CONDITIONS BY MID WEEK.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 AM HST SATURDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.
DISCUSSION...THOMAS
AVIATION...GIBBS
MARINE...TSAMOUS
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