709
FXHW60 PHFO 191511
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
511 AM HST FRI DEC 19 2025
UPDATE
THUNDERSTORMS HAVE BEEN ADDED TO THE FORECAST FOR THE CENTRAL
ISLANDS (MAUI COUNTY AND OAHU) AND THE SURROUNDING WATERS, AS
THUNDERSTORMS HAVE DEVELOPED AND ARE MOVING NORTHWARD.
SYNOPSIS
A WEAKENING TROUGH NEAR KAUAI WILL CONTINUE TO BRING SHOWERS TO
THE GARDEN ISLE TODAY. ADDITIONAL MOISTURE MOVING INTO THE ISLANDS
WILL CONTINUE THE CHANCE FOR SHOWERS STATEWIDE THROUGH THE
WEEKEND. SOUTHERLY WINDS THROUGH THE WEEKEND WILL GIVE WAY TO
RETURNING TRADE WINDS MONDAY, WHICH WILL CARRY SHOWERS INTO THE
ISLANDS EARLY NEXT WEEK.
SYNOPSIS
A WEAKENING TROUGH NEAR KAUAI WILL CONTINUE TO BRING SHOWERS TO
THE GARDEN ISLE TODAY. ADDITIONAL MOISTURE MOVING INTO THE ISLANDS
WILL CONTINUE THE CHANCE FOR SHOWERS STATEWIDE THROUGH THE
WEEKEND. SOUTHERLY WINDS THROUGH THE WEEKEND WILL GIVE WAY TO
RETURNING TRADE WINDS MONDAY, WHICH WILL CARRY SHOWERS INTO THE
ISLANDS EARLY NEXT WEEK.
DISCUSSION
A NORTHEAST TO SOUTHWEST ORIENTED TROUGH NEAR KAUAI BROUGHT
SHOWERS AND THUNDERSTORMS TO THE AREA OVERNIGHT. WHILE ADDITIONAL
SHOWERS AND EVEN SOME THUNDERSTORMS REMAIN POSSIBLE, THE MAIN
THREAT FOR FLOODING HAS DIMINISHED, AND SO THE FLOOD WATCH WAS
CANCELLED THIS MORNING.
THE FORECAST HAS BEEN UPDATED TO TREND TOWARDS THE NATIONAL BLEND
OF MODELS (NBM), HOWEVER THERE HAVEN'T BEEN ANY SIGNIFICANT
CHANGES WITH THE MORNING PACKAGE. A CHANGE FOR TODAY HAS BEEN AN
INCREASE IN POP FOR THE CENTRAL ISLANDS (MAUI COUNTY AND OAHU).
THE NBM APPEARS TO HAVE LOCKED ON TO AN AREA OF CLOUDS AND SHOWERS A
LITTLE OVER 100 MILES SOUTH OF OAHU AT 330 AM, THAT IS MOVING
NORTH. THUNDERSTORMS REMAIN IN THE FORECAST FOR TODAY OVER AND
AROUND KAUAI, HOWEVER THERE ARE SOME INDICATORS IN THE MODELS TO
SUGGEST THAT THUNDERSTORMS COULD STILL BE POSSIBLE TONIGHT AND
TOMORROW, AND EVEN OVER THE CENTRAL ISLANDS. HOWEVER THERE IS
CONFLICTING GUIDANCE, SO CONFIDENCE IS LOW, SO HAVE LEFT
THUNDERSTORMS ONLY IN FOR TODAY NEAR KAUAI.
THE TROUGH IS EXPECTED TO WEAKEN OVER THE NEXT 24 HOURS, ALTHOUGH
SOUTHERLY WINDS WILL CONTINUE OVER THE REGION. THIS WILL CONTINUE
TO BRING MOISTURE UP OVER THE ISLANDS INTO SATURDAY. A SURFACE LOW
DEVELOPING ABOUT 1100 MILES NORTHWEST OF KAUAI ON SATURDAY WILL
HELP TO BRING ADDITIONAL MOISTURE NORTHWARD, HOWEVER THE LOW IS
EXPECTED TO STAY FAR TO THE NORTHWEST OF THE ISLANDS, SO NOT
EXPECTING THOSE SHOWERS TO IMPACT US.
SUNDAY SHOULD SEE OUR WINDS BECOME SOUTHEASTERLY, AND BY MONDAY
WE EXPECT TO SEE TRADE WINDS FILTERING BACK INTO THE ISLANDS. AS
THE TRADE WINDS BUILD BACK, MOISTURE UPSTREAM WILL BE CARRIED IN
ON THE TRADES, BRINGING SHOWERS BACK TO THE MORE TYPICAL WINDWARD
AND MAUKA AREAS. DURING THE SECOND HALF OF THE WEEK, THE HIGH
PRESSURE RESPONSIBLE FOR THE RETURNING TRADES IS EXPECTED TO BE
SINKING SOUTHWARD, WHICH WILL SHIFT OUR WINDS TO A MORE
SOUTHEASTERLY DIRECTION. WILL NEED TO MONITOR FUTURE MODELS RUNS
TO DETERMINE ANY SIGNIFICANT CHANGES IN SHOWER .
AVIATION
THE TROUGH NEAR KAUAI CONTINUES TO BRING CLOUDS AND SHOWERS TO
KAUAI IN THE SOUTHERLY FLOW NEAR THE ISLANDS. AIRMET SIERRA IS IN
EFFECT FOR KAUAI FOR THE RESULTING MOUNTAIN OBSCURATION, AND THAT
IS EXPECTED TO CONTINUE THROUGH MUCH OF THE DAY. CLOUDS AND
SHOWERS ARE POSSIBLE TODAY OVER THE REMAINING ISLANDS,
PARTICULARLY OVER OAHU AND THE ISLANDS OF MAUI COUNTY. THESE
CLOUDS AND SHOWERS COULD AT TIMES PRODUCE MOUNTAIN OBSCURATION OR
MVFR CONDITIONS, WHICH COULD RESULT IN THOSE AREAS BEING PLACED
UNDER AN AIRMET. ANTICIPATE THE BIG ISLAND TO REMAIN MOSTLY UNDER
VFR CONDITIONS TODAY.
MARINE
A SURFACE TROUGH, NEAR KAUAI, WILL CONTINUE TO BRING SCATTERED TO
NUMEROUS SHOWERS TO MUCH OF THE COASTAL WATERS TODAY WITH
ISOLATED THUNDERSTORMS POSSIBLE OVER THE WESTERN WATERS. ASIDE
FROM ANY GUSTY WINDS ASSOCIATED WITH PASSING THUNDERSTORMS,
GENERALLY GENTLE TO LOCALLY MODERATE SOUTHERLY WINDS WILL PREVAIL
EAST OF THE TROUGH. THE SMALL CRAFT ADVISORY (SCA) FOR WATERS
SURROUNDING KAUAI AND OAHU HAS BEEN CANCELLED, AS COMBINED SEAS
HAVE LOWERED BELOW ADVISORY LEVELS (10 FT). BY LATE THIS WEEKEND,
EASTERLY TRADE WINDS WILL GRADUALLY BUILD FROM EAST TO WEST WITH
THE POTENTIAL FOR SCA CONDITIONS OVER THE WINDIER WATERS AND
CHANNELS AROUND MAUI COUNTY AND THE BIG ISLAND. EXPECT TRADES TO
STRENGTHEN FURTHER EARLY NEXT WEEK AS SURFACE HIGH PRESSURE BUILDS
TO THE NORTH.
THE CURRENT MODERATE, MEDIUM PERIOD, NORTH NORTHWESTERLY SWELL
(340-350 DEG) PEAKED YESTERDAY EVENING AND HAS BEEN SLOWLY FADING
SINCE. THUS, THE HIGH SURF ADVISORY (HSA) FOR NORTH AND WEST
FACING SHORES OF NIIHAU, KAUAI, OAHU, MOLOKAI, AND NORTH FACING
SHORES OF MAUI HAS BEEN CANCELLED. HOWEVER, THIS NORTH NORTHWEST
SWELL WILL REMAIN ELEVATED TODAY AND KEEP SURF JUST SHY OF
ADVISORY LEVELS THROUGH EARLY SATURDAY. A MODERATE, MEDIUM
PERIOD, NORTHERLY SWELL IS PROGGED TO ENTER THE WATERS LATE
SATURDAY AND MAY BUMP SURF BACK UP TO NEAR ADVISORY LEVELS
SATURDAY NIGHT INTO SUNDAY. SUNDAY NIGHT INTO EARLY NEXT WEEK, THE
SWELL FADES AND SHOULD ALLOW SURF TO DROP TO BELOW SEASONAL
AVERAGES.
EAST FACING SHORES WILL REMAIN SMALL GIVEN THE LACK OF TRADE WINDS
UPSTREAM OF THE ISLANDS, BUT AREAS EXPOSED TO THE NORTH SWELL
WILL SEE AN UPTICK THROUGH THE REST OF THE WEEK. AS TRADE WINDS
GRADUALLY STRENGTHEN LATER THIS WEEKEND, EAST FACING SHORES COULD
BECOME ROUGH AND CHOPPY SUNDAY THROUGH EARLY NEXT WEEK. SURF ALONG
SOUTH FACING SHORES WILL REMAIN SMALL THROUGH REMAIN FLAT TO TINY
THROUGH THE WEEKEND INTO EARLY NEXT WEEK.
FIRE WEATHER
SHOWERS WILL CONTINUE, ALONG WITH LIGHT SOUTHERLY WINDS AND
GENERALLY HIGH RELATIVE HUMIDITIES. THIS WILL KEEP CONDITIONS
BELOW CRITICAL FIRE THRESHOLDS THROUGH THE NEXT FEW DAYS. LONGER
RANGE FORECAST SHOW LITTLE CHANCE FOR DANGEROUS FIRE WEATHER WELL
INTO NEXT WEEK.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...M BALLARD
DISCUSSION...M BALLARD
AVIATION...M BALLARD
MARINE...THOMAS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page