879
FXHW60 PHFO 111317
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
317 AM HST SUN OCT 11 2026
SYNOPSIS
MOISTURE WILL DECREASE THROUGH MONDAY. LIGHT TO MODERATE
BACKGROUND TRADE WINDS WILL PREVAIL, ALLOWING SEA BREEZES TO
DEVELOP IN SHELTERED LEEWARD AREAS. A BRIEF INCREASE IN SHOWERS IS
EXPECTED MONDAY NIGHT, MAINLY ON THE BIG ISLAND, BEFORE WE RETURN
TO RELATIVELY DRY TRADES THROUGH THE END OF NEXT WEEK. WIND
SPEEDS ARE FORECAST TO INCREASE FROM FRIDAY INTO NEXT WEEKEND.
DISCUSSION
SATELLITE SHOWED MOSTLY CLOUDY SKIES OVER KAUAI COUNTY AND THE
BIG ISLAND THIS MORNING, AND PARTLY CLOUDY SKIES ELSEWHERE. RADAR
INDICATED ISOLATED SHOWERS OVER KAUAI COUNTY, WITH A LARGER AREA
OF SHOWERS TO THEIR SOUTH AND WEST. WINDS WERE GENERALLY OUT OF
THE EAST AT 5 TO 10 MPH.
A WEAK UPPER LEVEL LOW JUST TO THE EAST OF THE BIG ISLAND WILL
WEAKEN FURTHER AND THEN MOVE OFF TO THE NORTHEAST OVER THE NEXT
FEW DAYS. THIS WILL HAVE VIRTUALLY NO IMPACT AT THE SURFACE, APART
FROM SOME SHADE FROM INCREASED CLOUDINESS. TRADE WINDS WILL
CONTINUE TO BUILD BACK IN - INITIALLY FROM THE EAST, THEN BECOMING
NORTHEAST AND STRENGTHENING LATE THIS COMING WEEK.
WINDS ARE EXPECTED TO BE LIGHT ENOUGH FOR SEA-BREEZES TO DEVELOP
IN SOME AREAS AGAIN TODAY, LEADING TO AN INCREASED CHANCE OF
SHOWERS IN LEEWARD AREAS. THIS WAS ALREADY IN THE FORECAST, AND
WAS MAINTAINED.
WE WILL SEE AN INCREASE IN THE CHANCE OF SHOWERS MONDAY NIGHT
INTO TUESDAY AS AN AREA OF ENHANCED MOISTURE MOVES IN FROM THE
EAST. THIS MOISTURE WILL BE MOST PRONOUNCED NEAR THE BIG ISLAND,
BUT WILL IMPACT THE WINDWARD AREAS OF ALL ISLANDS. SOME
ADJUSTMENTS WERE PREVIOUSLY MADE TO ACCOUNT FOR THIS, AND WE HAVE
FURTHER INCREASED THE CHANCE OF RAIN DURING THIS PERIOD IN THIS
MORNING'S FORECAST AS CONFIDENCE INCREASES.
AVIATION
LIGHT TO MODERATE TRADES THROUGH THE PERIOD. LOW CIGS AND SHRA
SHOULD PRIMARILY IMPACT WINDWARD AND MAUKA LOCATIONS WITH SOME
ISOL SHRA OVER LEEWARD AREAS. MVFR CONDS POSSIBLE IN SHRA,
OTHERWISE VFR PREVAILS.
AIRMET SIERRA IS IN EFFECT FOR MTN OBSC FOR PORTIONS OF ALL
ISLANDS. CONDS SHOULD IMPROVE IN THE MID MORNING HOURS.
MARINE
MODERATE TO FRESH TRADE WINDS CONTINUE THIS WEEKEND, THOUGH
WEAKER WINDS WILL REMAIN IN PLACE OVER THE WESTERN WATERS AS A
TROUGH LINGERS WEST OF THE AREA. TRADE WINDS THEN DECREASE THIS
UPCOMING WEEK INTO THE LIGHT TO MODERATE RANGE THROUGH MUCH OF THE
WEEK WITH SLIGHT DAY TO DAY FLUCTUATIONS. STRENGTHENING TRADES
ARE POSSIBLE TOWARDS THE END OF THE WEEK AS HIGH PRESSURE BUILDS
NORTH OF THE AREA.
A LONG-PERIOD SOUTH SWELL WILL PEAK TODAY AND HOLD THROUGH MONDAY,
PRODUCING ELEVATED SURF ALONG SOUTH AND WEST-FACING SHORES, BUT IT
WILL REMAIN BELOW ADVISORY LEVELS. SOUTH SHORE SURF WILL DECLINE
GRADUALLY TUESDAY INTO WEDNESDAY, BUT A NEW LONG-PERIOD SOUTH SWELL
ARRIVING LATE WEDNESDAY WILL PROVIDE ANOTHER BUMP IN SURF FOR THURSDAY
AND FRIDAY.
THE SHORT-PERIOD NORTH-NORTHWEST SWELL GENERATED BY LOW PRESSURE
TO THE NORTHWEST OF THE ISLANDS WILL FADE TODAY, WHILE A NEW
SMALL, LONG-PERIOD SWELL PEAKS. THIS WILL KEEP SMALL SURF
CONTINUING TODAY FOR NORTH-FACING SHORES, BUT SURF DECLINES ON
MONDAY AS THIS SWELL FADES. ANOTHER SMALL, LONG-PERIOD NORTHWEST
SWELL IS FORECAST TO ARRIVE ON MONDAY AND PEAK TUESDAY, WHICH WILL
BOOST NORTH SHORE SURF BACK TO MODERATE LEVELS. A MODERATE NORTH-
NORTHWEST SWELL IS POSSIBLE BY THE END OF THE WEEK, DEPENDING ON
THE EVOLUTION OF A PROJECTED LOW IN THE NORTH PACIFIC. HOWEVER,
CONFIDENCE IS LOW GIVEN DIFFERENCES IN MODEL SOLUTIONS WITH THIS
FEATURE.
SURF ALONG EAST-FACING SHORES WILL REMAIN SMALL AS LOCAL WINDS
REMAIN FAIRLY WEAK WITH ONLY SLIGHT VARIATIONS EACH DAY. SMALL,
MODERATE-PERIOD WEST AND EAST SWELLS GENERATED BY MULTIPLE PACIFIC
TROPICAL CYCLONES CONTINUE TO MOVE THROUGH THE ISLANDS THROUGH
MONDAY.
FIRE WEATHER
LIGHT TO MODERATE TRADES WILL BE WITH US INTO THE MIDDLE OF THE
COMING WEEK. MOISTURE WILL DECREASE TODAY THROUGH MONDAY, BRINGING
RH VALUES DOWN TO NEAR CRITICAL VALUES ON PARTS OF THE BIG ISLAND
MONDAY, INCLUDING NEAR KONA. HOWEVER, WINDS WILL TOO LIGHT FOR
ANY FIRE WEATHER HEADLINES. INVERSION HEIGHTS ARE AROUND 5500-6500
FEET ACROSS THE EASTERN END OF THE STATE.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...PARKER
AVIATION...WALSH
MARINE...QUESADA
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