584
FXHW60 PHFO 100147
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
347 PM HST WED SEP 9 2026
SYNOPSIS
RESIDUAL MOISTURE FROM TROPICAL STORM LOWELL STRETCHING INTO TO
BIG ISLAND AND PORTIONS OF MAUI COUNTY MAY BRING A RENEWED THREAT
OF HEAVY SHOWERS THROUGH THIS EVENING, WHILE SEA BREEZES TRIGGER
SPOTTY AFTERNOON SHOWERS ACROSS THE REST OF THE STATE. TRADE WINDS
WILL SLOWLY BUILD OVER THE STATE LATE TONIGHT INTO THURSDAY,
THOUGH MOISTURE REMAINS ELEVATED ACROSS MUCH OF THE STATE. DRIER
TRADE WIND WEATHER IS EXPECTED TO DEVELOP THURSDAY NIGHT INTO
EARLY NEXT WEEK.
DISCUSSION
AFTERNOON SATELLITE WATER VAPOR IMAGERY SHOWS DRIER AIR IN THE LOW
AND MID LEVELS SPREADING SOUTH INTO MAUI COUNTY, WITH REMNANT
MOISTURE FROM TROPICAL STORM LOWELL LINGERING ACROSS THE BIG
ISLAND. SCATTERED SHOWERS HAVE DEVELOPED FROM MOLOKAI SOUTHWARD.
DESPITE PRECIPITABLE WATER AROUND 2" FURTHER SOUTH, PEAK RAINFALL
RATES OVER THE BIG ISLAND HAVE ONLY BEEN AROUND 0.50"/HR SO FAR.
HI-RES ENSEMBLES SHOW LITTLE CHANGE IN RAINFALL RATES THROUGH THE
REST OF THE AFTERNOON, INCREASING MAINLY ON THE WINDWARD SIDES OF
THE ISLANDS TONIGHT INTO THURSDAY MORNING AS THE BAND OF TROPICAL
MOISTURE SHIFTS WESTWARD ACROSS THE STATE AND EASTERLY FLOW
STRENGTHENS SLIGHTLY, AND A FEW SHOWERS MAY SPILL OVER ONTO THE
LEEWARD SIDE. INSTABILITY REMAINS MARGINAL TOMORROW, BUT ENOUGH
TO WARRANT A SLIGHT CHANCE OF THUNDERSTORMS WITH LOCALLY HEAVIER
RAINFALL OVER THE INTERIOR OF THE BIG ISLAND THIS AFTERNOON AND
AGAIN THURSDAY AFTERNOON.
FRIDAY THROUGH EARLY NEXT WEEK, A LARGE UPPER LEVEL LOW WELL
NORTHEAST OF THE STATE AND WEAK TROUGHING ALOFT WILL ALLOW FOR
LIGHT TO MODERATE TRADE WINDS TO PREVAIL WITH A MORE TYPICAL TRADE
SHOWERS CONCENTRATED ALONG WINDWARD LOCATIONS IN THE NIGHT TO
EARLY MORNING HOURS. HUMIDITY WILL ALSO DECREASE DURING THIS
PERIOD AS LOW-LEVEL DRYING OCCURS.
AVIATION
TROPICAL STORM LOWELL REMAINS NORTH OF THE MAIN HAWAIIAN ISLANDS,
AND WILL CONTINUE TO WEAKEN AND MOVE FURTHER AWAY FROM THE
ISLANDS. SURFACE OBSERVATIONS ALONG WITH SATELLITE DERIVED WINDS
INDICATE TRADE WINDS ARE STARTING TO AFFECT THE EASTERN ISLANDS
ALONG WITH THE AFTERNOON SEA BREEZE. THE TRADE WINDS ARE EXPECTED
TO SPREAD THROUGH THE REMAINING ISLANDS, AND PERSIST INTO
TOMORROW.
MOISTURE BEING PULLED NORTH FROM TROPICAL STORM LOWELL, AND THIS
COMBINED WITH SEA BREEZE WINDS HAVE ENHANCED CLOUDS AND SHOWER
ACTIVITY OVER THE BIG ISLAND, MAUI, MOLOKAI AND LANAI. THESE
ISLANDS ARE EXPERIENCED PERIODS OF MVFR CONDITIONS, AND EVEN LOWER
CONDITIONS ON THE BIG ISLAND, AS SUCH, AIRMET SIERRA FOR MOUNTAIN
OBSCURATION REMAINS IN EFFECT AND WILL BE EXPANDED TO COVER
MOLOKAI AND LANAI. THESE ADDITIONAL CLOUDS AND SHOWERS WILL
CREATE MORE MOUNTAIN OBSCURATION, POTENTIALLY LASTING INTO EARLY
THURSDAY MORNING. GIVEN THE LOWER PWAT VALUES FOR THE WESTERN ISLANDS,
WILL LIKELY END THE AIRMET FOR KAUAI.
WITH LIGHT SOUTHERLY WINDS EXPECTED, NOT ANTICIPATING ANY AIRMETS
FOR TURBULENCE TODAY.
MARINE
A SURFACE TROUGH OVER THE STATE WILL GRADUALLY MOVE WESTWARD
TONIGHT. AS THE TROUGH MOVES WEST, MODERATE TO LOCALLY FRESH
TRADE WINDS WILL GRADUALLY RETURN FROM EAST TO WEST ACROSS THE
ISLAND CHAIN THROUGH THROUGH THURSDAY AND THEN PERSIST INTO THE
WEEKEND. THE SURFACE TROUGH WILL BRING SOME SCATTERED SHOWERS
ACROSS THE AREA THROUGH THURSDAY.
THE CURRENT MODERATE MID-PERIOD SOUTH SWELL CONTINUES TO DECLINE
THIS AFTERNOON AND SURF HAS DROPPED BELOW ADVISORY THRESHOLDS FOR
SOUTH FACING SHORES. THIS SWELL WILL CONTINUE TO STEADILY DECLINE
OVER THE NEXT FEW DAYS WITH BELOW AVERAGE SURF EXPECTED BY THE
WEEKEND.
SURF ALONG EAST FACING SHORES WILL GRADUALLY DECREASE TONIGHT AND
WILL REMAIN NEAR SEASONAL AVERAGES THROUGH AROUND SATURDAY DUE TO
EAST AND NORTHEAST SWELLS GENERATE BY FORMER TROPICAL CYCLONES.
SURF ALONG NORTH FACING SHORES CONTINUES TO RECEIVE A SMALL BUMP
DUE TO LOWELL. THIS SHORT-PERIOD NORTHWEST SWELL WILL QUICKLY
FADE, ALLOWING SURF TO BECOME TINY ALONG NORTH FACING SHORES ON
THURSDAY AS LOWELL WEAKENS AND TRACKS AWAY FROM THE ISLANDS.
FIRE WEATHER
FIRE WEATHER RISK WILL REMAIN LOW THE NEXT SEVERAL DAYS DUE LIGHT
WINDS AND LINGERING MOISTURE. EXPECT A SLIGHT CHANCE OF
THUNDERSTORMS OVER THE BIG ISLAND THIS AFTERNOON AND AGAIN
THURSDAY AFTERNOON. TEMPERATURE INVERSION HEIGHTS ARE EXPECTED TO
REMAIN ELEVATED OR WEAK.
HFO WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH UNTIL 6 PM HST THIS EVENING FOR BIG ISLAND EAST-BIG
ISLAND INTERIOR-BIG ISLAND NORTH-BIG ISLAND SOUTH-BIG ISLAND
SOUTHEAST-BIG ISLAND SUMMITS-KOHALA-KONA.
DISCUSSION...SS
AVIATION...PHILLIPS
MARINE...KINO
FIRE WEATHER...SS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page