025
FXHW60 PHFO 260646
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
846 PM HST SAT APR 25 2026
SYNOPSIS
A HIGH PRESSURE SYSTEM FAR NORTH OF THE HAWAIIAN ISLANDS WILL
SLOWLY DRIFT EAST OVER THE NEXT FEW DAYS, THE RIDGE WILL REMAIN
IN PLACE NORTH OF THE REGION KEEPING EASTERLY TRADE WINDS IN THE
FORECAST THROUGH THE END OF NEXT WEEK. AN UPPER LEVEL DISTURBANCE
MOVES OVER THE ISLANDS ON TUESDAY AND THEN DRIFTS SLOWLY EASTWARD,
INCREASING CLOUDS AND SHOWERS ACROSS THE REGION LASTING INTO THE
END OF NEXT WEEK. SHOWER ACTIVITY DURING THIS TIME PERIOD WILL
FAVOR WINDWARD MOUNTAIN AREAS MAINLY IN THE OVERNIGHT TO EARLY
MORNING HOURS.
SHORT TERM UPDATE
THE SATELLITE PICTURE THIS EVENING SHOWS A WEAK LOW LEVEL TROUGH
PASSING THROUGH THE HAWAII REGION. EXPECT OVERNIGHT DIURNAL
SHOWER ACTIVITY TO INCREASE WITH TEMPERATURE INVERSION HEIGHTS
RISING TO AROUND 8,000 FEET AS THIS 700 MB TROUGH PASSES THROUGH
THE ISLAND CHAIN. BY SUNDAY A WEAK UPPER LEVEL TROUGH MOVES IN
FROM THE NORTH, KEEPING TEMPERATURE INVERSION HEIGHTS ELEVATED AND
PASSING SHOWERS IN THE FORECAST FAVORING WINDWARD MOUNTAIN AREAS
IN THE OVERNIGHT THROUGH EARLY MORNING HOURS LINGERING INTO
MONDAY MORNING.
THE FORECAST GRIDS LOOK REASONABLE WITH NO EVENING UPDATES.
PREVIOUS DISCUSSION
ISSUED AT 343 PM HST SAT APR 25 2026
ISOLATED LIGHT SHOWERS WERE SEEN ON RADAR THIS AFTERNOON OVER THE
WINDWARD AREAS OF MOST ISLANDS, WITH THE HIGHEST CONCENTRATION OF
SHOWERS OVER THE KAU DISTRICT ON BIG ISLAND. CLOUDS WERE ALSO
CONCENTRATED OVER WINDWARD AND MAUKA AREAS, AND OVER THE KONA
REGION OF BIG ISLAND. SHOWERS AND CLOUDS WILL DECREASE IN MOST
AREAS AROUND AND ESPECIALLY AFTER SUNSET.
UPPER LEVEL RIDGING TO OUR NORTHWEST WILL CONTINUE FOR THE NEXT
FEW DAYS, AND THIS WILL HELP KEEP TRADES WINDS GOING. MODELS ARE
CONSISTENT SHOWING A LITTLE MORE INSTABILITY OVER BIG ISLAND
TOMORROW AFTERNOON, AND THE CHANCE OF SHOWERS WAS INCREASED OVER
MAINLY THE SOUTHERN HALF OF THE ISLAND. BY TUESDAY NIGHT, THERE
IS INCREASING CONFIDENCE THAT A FAST MOVING UPPER LEVEL LOW WILL
MOVE OVER THE ISLANDS FROM THE NORTHWEST, BRINGING WITH IT COLD
AIR ALOFT. MOISTURE WILL BE LIMITED, BUT THERE STILL SHOULD BE AN
UPTICK IN SHOWER COVERAGE AND STRENGTH TUESDAY NIGHT AND
WEDNESDAY. THE NBM GUIDANCE WAS UNUSUALLY DRY THROUGH THIS PERIOD,
AND WAS NOT USED.
THIS LOW MOVES OFF QUICKLY LATE WEDNESDAY INTO WEDNESDAY NIGHT,
AND A NEW UPPER LEVEL RIDGE TO OUR NORTHWEST WILL TAKE OVER.
THEREFORE, TRADES WILL CONTINUE AND STRENGTHEN FROM WEDNESDAY
THROUGH NEXT WEEKEND. WINDS STRONG ENOUGH TO WARRANT A SMALL CRAFT
ADVISORY ARE LIKELY TO DEVELOP, BUT IT'S TOO FAR OUT IN TIME FOR
DETAILS. APART FROM TUESDAY NIGHT AND WEDNESDAY, EXPECT TYPICAL
TRADE SHOWERS MAINLY WINDWARD AND MAUKA.
AVIATION
ISSUED AT 343 PM HST SAT APR 25 2026
MODERATE TO LOCALLY BREEZY TRADES THROUGH EARLY NEXT WEEK. LOW
CIGS AND SHRA CAN BE EXPECTED OVER WINDWARD AND MAUKA LOCATIONS. MVFR
CONDS EXPECTED IN HEAVIER SHRA, OTHERWISE VFR PREVAILS.
NO AIRMETS IN EFFECT.
MARINE
ISSUED AT 343 PM HST SAT APR 25 2026
HIGH PRESSURE NORTH OF THE STATE IS PRODUCING MODERATE TO FRESH
TRADE WINDS THIS AFTERNOON. A SLIGHT DECREASE IS EXPECTED TONIGHT
INTO EARLY NEXT WEEK AS A WEAK TROUGH TRACKS WEST ACROSS THE
STATE. THE TROUGH SHOULD BRING AN INCREASE OF SHOWER COVERAGE,
ESPECIALLY OVER WINDWARD WATERS. HIGH PRESSURE WILL REBUILD FAR
NORTH OF THE STATE TOWARDS THE MIDDLE OF NEXT WEEK, WHICH SHOULD
BRING THE RETURN OF MODERATE TO LOCALLY STRONG TRADES.
A MEDIUM-PERIOD NORTHWEST SWELL PEAKS TONIGHT INTO SUNDAY, PRODUCING
SMALL TO MODERATE SURF FOR NORTH AND WEST-FACING SHORES, BEFORE
GRADUALLY DECLINING THROUGH EARLY NEXT WEEK. A HURRICANE-FORCE LOW
TRACKING ACROSS THE ALEUTIAN ISLANDS TONIGHT SHOULD SEND A MODERATE
NORTHWEST SWELL TOWARDS HAWAII AROUND THE MIDDLE OF NEXT WEEK.
SHORT-PERIOD NORTHEASTERLY ENERGY IS BEGINNING TO DECREASE THIS
AFTERNOON, WHICH WILL KEEP BELOW AVERAGE SURF ALONG EASTERN EXPOSURES
FOR THE FIRST HALF OF NEXT WEEK DUE TO THE LACK OF ANY STRONG TRADE
WIND ACTIVITY. LOCALLY STRONG TRADE WINDS COULD RETURN DURING THE
LATTER HALF OF NEXT WEEK, WHICH COULD BRING ROUGH AND CHOPPY SURF
WITH NEAR NORMAL WAVE HEIGHTS.
SMALL BACKGROUND ENERGY FROM THE WEST WILL CONTINUE TO LINGER THROUGH
TODAY AND FADE OUT ON SUNDAY. A SMALL SOUTHWEST BUMP FROM THE
TASMAN SEA IS EXPECTED TO SLOWLY FILL IN TONIGHT AND PEAK ON SUNDAY.
NO SIGNIFICANT SOUTH SWELL IS EXPECTED THROUGH THE FIRST HALF OF NEXT
WEEK. A FETCH OF GALES PASSING EAST OF NEW ZEALAND TODAY COULD PRODUCE
A SMALL SOUTH-SOUTHWEST SWELL FOR NEXT WEEKEND.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...BOHLIN
PREVIOUS DISCUSSION...PARKER
AVIATION...WALSH
MARINE...QUESADA
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