309
FXHW60 PHFO 090625
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
825 PM HST SAT AUG 8 2026
SYNOPSIS
BREEZY TRADES WILL FOCUS LOW CLOUDS AND SHOWERS ACROSS WINDWARD
AND MAUKA AREAS THROUGH THE MIDDLE OF NEXT WEEK. A PLUME OF
MOISTURE MOVING SOUTH OF THE ISLANDS WILL INCREASE RAIN CHANCES
OVER THE EASTERN END OF THE STATE THROUGH MONDAY, FOLLOWED BY
DRIER CONDITIONS THROUGH MID-WEEK. BREWING DISTURBANCES WITHIN THE
TROPICS WILL NEED TO BE MONITORED FOR MORE ORGANIZED DEVELOPMENT
THE NEXT SEVERAL DAYS.
SHORT TERM UPDATE
UPPER RIDGING CENTERED FAR NORTHEAST OF THE STATE WITH ITS AXIS
DRAPED SOUTHWEST OVER THE REGION WAS THE CONTROLLING FEATURE TO
TODAY'S PARTLY SUNNY AND RELATIVELY DRY CONDITIONS. EVENING IR
SATELLITE IMAGERY DEPICTING AN AREA OF HIGHER MOISTURE SOUTHEAST
OF THE STATE THAT WILL TRACK SOUTH OF THE ISLAND CHAIN TONIGHT.
THIS MORE MOIST AIR WILL PRIMARILY PASS BY BIG ISLAND AND GRAZE
THE SMALLER ISLANDS...OR BE THE IMPETUS TO MORE, MAINLY WINDWARD,
SHOWERS INTO THE EARLY SUNDAY MORNING HOURS. UPPER RIDGING WILL
SUBTLY BACK OFF THE NEXT COUPLE OF DAYS. THE RESULT WILL BE A
DEEPER, MORE MOIST BOUNDARY LAYER OVER THE STATE. THIS WILL
PRODUCE A CLOUDIER AND WETTER SUNDAY, ESPECIALLY FOR THE WINDWARD
COMMUNITIES OF BIG ISLAND AND MAUI.
PREV DISCUSSION
ISSUED AT 351 PM HST SAT AUG 8 2026
HIGH PRESSURE TO THE FAR NORTHEAST AND A WEAK TROUGH APPROACHING
FROM THE SOUTHEAST WILL CONTINUE TO DRIVE BREEZY TRADES ACROSS THE
STATE THROUGH THE WEEKEND. SATELLITE IMAGERY SHOWS MOSTLY DRY
CONDITIONS PERSISTING ACROSS THE WESTERN HALF OF THE STATE THIS
AFTERNOON ALONG WITH SOME PASSING HIGH CIRRUS, AND INCREASING LOW
CLOUD AND SHOWER COVERAGE OVER THE EASTERN END. THESE CLOUDS AND
SHOWERS MOVING INTO WINDWARD SLOPES OF THE BIG ISLAND MARKS THE
LEADING EDGE OF A LARGER PLUME OF MOISTURE ASSOCIATED WITH THE
AFOREMENTIONED WESTWARD-MOVING SURFACE TROUGH PASSING SOUTH OF THE
STATE THIS WEEKEND. SOME OF THIS MOISTURE MAY TRACK UP THE ISLAND
CHAIN TO INCREASE WINDWARD AND MAUKA SHOWERS ACROSS MAUI,
MOLOKAI, AND POSSIBLY OAHU TONIGHT INTO SUNDAY, THOUGH THE HIGHEST
RAIN CHANCES REMAIN CENTERED OVER THE BIG ISLAND. FORECAST
SOUNDINGS INDICATE MODEST INSTABILITY OVER THE BIG ISLAND
TOMORROW. COMBINED WITH INCREASING TROPICAL MOISTURE AND DAYTIME
HEATING, THIS MAY PRODUCE AN ISOLATED THUNDERSTORM OR TWO OVER
INTERIOR SLOPES DURING THE AFTERNOON HOURS.
AS THE PRESSURE GRADIENT RELAXES SLIGHTLY IN RESPONSE TO THE
SURFACE TROUGH WEAKENING AND MOVING FARTHER WESTWARD AWAY FROM
THE STATE, MODERATE TO BREEZY TRADES ARE EXPECTED MONDAY THROUGH
ABOUT THURSDAY. DRIER AIR WILL FILL IN ACROSS THE ISLAND CHAIN
MIDWEEK, DROPPING DEW POINTS AND PROVIDING SOME RELIEF FROM THE
MUGGINESS.
BEYOND THURSDAY, FORECAST CONFIDENCE DECREASES, AS LOCAL WEATHER
WILL DEPEND ON THE POSSIBLE DEVELOPMENT AND PROGRESSION OF A
TROPICAL CYCLONE IN THE CENTRAL PACIFIC. THE NATIONAL HURRICANE
CENTER IS MONITORING AN EASTERLY WAVE ABOUT 1,400 MILES EAST-
SOUTHEAST OF THE STATE, ASSIGNING AN 80 PERCENT PROBABILITY OF
TROPICAL CYCLONE DEVELOPMENT OVER THE NEXT 7 DAYS. WHILE IT
REMAINS TOO EARLY TO DISCUSS SPECIFIC LOCAL IMPACTS, THIS FEATURE
WARRANTS CLOSE MONITORING OVER THE COMING DAYS.
AVIATION
MODERATE TO FRESH TRADES EXPECTED FOR THE NEXT SEVERAL DAYS. LOW
CIGS AND SHRA SHOULD MAINLY IMPACT WINDWARD AND MAUKA SPOTS. ISOL
IFR AND SOME MVFR CONDS LIKELY IN HEAVIER SHRA, OTHERWISE VFR
PREVAILS.
AIRMET SIERRA IS IN EFFECT FOR MTN OBSC FOR WINDWARD LOCATIONS OF
ALL ISLANDS.
AIRMET TANGO IS IN EFFECT FOR MOD TURB DOWNWIND OF ISLAND
TERRAIN. THIS AIRMET WILL LIKELY BE NEEDED FOR NEXT SEVERAL DAYS.
MARINE
ISSUED AT 351 PM HST SAT AUG 8 2026
FRESH TO LOCALLY STRONG TRADE WINDS WILL PERSIST THROUGH AT LEAST
WEDNESDAY AS HIGH PRESSURE REMAINS ANCHORED NORTHEAST OF THE
STATE. A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE TYPICAL
WINDY CHANNELS AND WATERS AROUND MAUI COUNTY AND THE BIG ISLAND
THROUGH SUNDAY AFTERNOON. THIS ADVISORY MANY NEED TO BE EXTENDED
FURTHER, AS BORDERLINE CONDITIONS WILL PREVAIL THROUGH AT LEAST
WEDNESDAY. LATER IN THE WEEK, THE FOCUS WILL SHIFT TO THE DEEP
TROPICS SOUTHEAST OF THE STATE. A TROPICAL CYCLONE COULD DEVELOP
AND HAVE AN EFFECT ON LOCAL WINDS, SEAS AND WEATHER AS EARLY AS
FRIDAY.
CONTINUED SMALL OVERLAPPING SOUTH-SOUTHWEST SWELLS WILL PRODUCE
SOUTH SHORE SURF NEAR AUGUST AVERAGE THIS WEEKEND AND NEAR TO
ABOVE AVERAGE MONDAY AND TUESDAY. A LARGER SWELL WILL ARRIVE
TUESDAY NIGHT AND MAY PUSH SURF TO THE HIGH SURF ADVISORY LEVEL
LATE WEDNESDAY THROUGH FRIDAY. THIS SWELL SHOULD SLOWLY DECREASE
NEXT WEEKEND.
ALONG EAST-FACING SHORES, SHORT-PERIOD TRADE WIND SWELL WILL
GENERATE SURF JUST BELOW AUGUST AVERAGE THROUGH THURSDAY.
DEPENDING ON HOW POTENTIAL TROPICAL CYCLONE DEVELOPMENT PLAYS OUT
SOUTHEAST OF THE ISLANDS, AN INCREASE IN SOUTHEAST SWELL IS
POSSIBLE FRIDAY AND NEXT WEEKEND. ASIDE FROM WRAPPING TRADE WIND
ENERGY, SURF ALONG NORTH-FACING SHORES WILL REMAIN FLAT TO TINY
THROUGH THE WEEK.
DUE TO A COMBINATION OF PEAK MONTHLY HIGH TIDES AND WATER LEVELS
RUNNING HIGHER THAN PREDICTED IN A FEW LOCATIONS, MINOR COASTAL
FLOODING WILL BE POSSIBLE AROUND THE AFTERNOON HIGH TIDE AS EARLY
AS SUNDAY, WITH PEAK CONDITIONS MONDAY THROUGH WEDNESDAY.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 PM HST SUNDAY FOR ALENUIHAHA
CHANNEL-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS-
MAALAEA BAY-PAILOLO CHANNEL.
DISCUSSION...FARRIS
AVIATION...WALSH
MARINE...WROE
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