819
FXHW60 PHFO 131357
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
357 AM HST SAT DEC 13 2025
SYNOPSIS
SOUTHERLY WINDS WILL BE ON THE INCREASE TODAY AHEAD OF A FRONT
APPROACHING THE ISLANDS FROM THE NORTHWEST. THE FRONT WILL BEING
ENHANCED SHOWERS AND ISOLATED THUNDERSTORMS TO THE WESTERN END OF
THE STATE SUNDAY THROUGH MONDAY NIGHT. ADDITIONAL UNSETTLED WET
WEATHER WILL BE POSSIBLE DURING THE MIDDLE AND LATTER HALF OF THE
NEW WEEK AS ANOTHER FRONT APPROACHES, THEN STALLS ACROSS THE
WESTERN HALF OF THE STATE.
DISCUSSION
UNSETTLED WEATHER REMAINS THE MAIN STORY FOR THE FORECAST FOR MUCH
OF THE NEXT WEEK. THE FORECAST HAS LARGELY BEEN NUDGED TOWARDS THE
LATEST RUN OF THE NATIONAL BLEND OF MODELS (NBM), WITH THE
EXCEPTION OF THE WINDS FOR THE FIRST 36 HOURS OR SO WHICH HAVE
BEEN NUDGED TOWARDS THE HIGH RESOLUTION FV3. SOUTHERLY WINDS ARE
EXPECTED TO INCREASE OVER AND NEAR KAUAI TODAY, REACHING SMALL
CRAFT ADVISORY (SCA) LEVELS. SEE THE MARINE SECTION BELOW FOR MORE
DETAILS. POPS ARE LOWERED IN SOME AREAS AHEAD OF THE FRONT FOR
TODAY THROUGH SUNDAY BASED ON THE NBM. CONFIDENCE WAS HIGH ENOUGH
TO BACK OFF ON SOME OF THOSE POPS DUE TO THE NUMBER OF MODELS
THAT SUPPORTED THAT CHANGE. SIMILARLY, THUNDERSTORM AREAS HAVE
BEEN TWEAKED A LITTLE BASED ON THE LATEST GUIDANCE.
A TROUGH TO THE NORTHEAST WILL CONTINUE TO MOVE AWAY FROM THE
ISLANDS, AS A FRONT TO THE NORTHWEST MOVES CLOSER TO THE ISLANDS.
THERE IS GOOD MODEL AGREEMENT WITH THE GLOBAL MODELS WITH THIS
FRONT HOLDING TOGETHER AS IT APPROACHES KAUAI LATER TODAY. WINDS
ARE EXPECTED TO INCREASE AHEAD OF THE FRONT. THE FORECASTED WINDS
ARE HIGHER THAT THE NBM, AND HAVE BEEN TRENDED TOWARDS THE FV3,
WHICH AGREES WITH SOME OF THE OTHER HIGHER RESOLUTION MODEL
GUIDANCE. THE UKMET IS A LITTLE SLOWER THAT THE ECMWF AND GFS IN
BRINGING THE FRONT TO KAUAI, BUT GENERALLY THESE MODELS SHOW
THE RAIN FROM THE FRONT MOVING OVER THE COASTAL WATERS NORTHWEST
OF KAUAI LATER TODAY.
THE FRONT IS EXPECTED TO REACH KAUAI LATE TONIGHT (SATURDAY
NIGHT), AND MOVE TOWARD OAHU ON SUNDAY, BEFORE STALLING OUT IN THE
VICINITY OF KAUAI OR OAHU SUNDAY NIGHT INTO MONDAY. THERE IS GOOD
AGREEMENT IN THE GLOBAL MODELS WITH THE HANDLING OF THE UPPER
LEVEL DYNAMICS WITH THIS SYSTEM, WITH A STRONG SOUTHWESTERLY JET
HELPING TO PUSH THE SURFACE FRONT TOWARDS THE ISLANDS, AND PROVIDE
ADDITIONAL INSTABILITY THAT COULD RESULT IN LOCALLY HEAVY RAINFALL
AND ISOLATED THUNDERSTORMS. ALTHOUGH UNCERTAINTY REMAINS AS TO THE
EXACT LOCATION WHERE ANY BANDS OF HEAVY SHOWERS MAY FORM, A FLOOD
WATCH CONTINUES FOR KAUAI, NIIHAU, AND OAHU FROM MIDNIGHT SUNDAY
THROUGH LATE MONDAY NIGHT.
THE UPPER LEVEL FEATURE IS EXPECTED TO LIFT TUESDAY, AND BRING THE
SURFACE LOW WITH IT. THE SURFACE FRONT WILL ALSO LIFT AND WEAKEN,
ALTHOUGH LINGERING MOISTURE WILL REMAIN IN THE AREA. ANOTHER
SURFACE LOW FORMING NEAR THE DATELINE MONDAY, IS EXPECTED TO
APPROACH THE ISLANDS DURING THE MIDDLE TO LATTER PART OF THE NEW
WEEK. THE WILL BRING ANOTHER FRONT TO THE AREA FROM THE NORTHWEST,
AND IT TOO IS EXPECTED TO STALL OVER THE WESTERN END OF THE
STATE. THERE IS STILL SOME UNCERTAINTY WITH HOW STRONG THIS FRONT
WILL BE, BUT EXPECT ADDITIONAL SHOWERS TO CONTINUE THROUGH THE
REST OF THE WEEK.
AVIATION
MODERATE SOUTHERLY WINDS WILL STRENGTHEN TODAY, PARTICULARLY OVER
AND AROUND KAUAI AND OAHU AHEAD OF A FRONT APPROACHING FROM THE
NORTHWEST. THIS FRONT WILL BRING INCREASING CLOUDS AND SHOWERS,
MAINLY TO THE WESTERN END OF THE STATE THAT WILL BRING SOME
IFR/MVFR CONDITIONS. NO AIRMETS IN EFFECT, BUT AS THE CLOUDS AND
SHOWERS INCREASE, AIRMETS ARE POSSIBLE.
MARINE
AN APPROACHING FRONT MOVING SOUTHEAST IS EXPECTED TO ARRIVE ON
THE DOORSTEP OF KAUAI LATER THIS EVENING AND MAKE ITS WAY OVER THE
WESTERN END OF THE STATE THIS WEEKEND. GENTLE TO LOCALLY STRONG
SOUTH WINDS ARE EXPECTED THROUGH THE DAY WITH STRONG SOUTH TO
SOUTHWEST WINDS OVER MAINLY KAUAI WATERS. A SMALL CRAFT ADVISORY
HAS BEEN ISSUED OVER SELECT KAUAI WATERS THROUGH TONIGHT BEFORE
THE WINDS ARE EXPECTED TO EASE SUNDAY. SHOWERS AND THE POTENTIAL
FOR ISOLATED THUNDERSTORMS ARE EXPECTED ALONG THE FRONT THROUGH
SUNDAY.
A SURFACE LOW FAR NORTHWEST OF THE OFFSHORE WATERS WILL DEVELOP
EARLY NEXT WEEK, AND WILL LIKELY SEND ANOTHER FRONT TO THE ISLANDS
THAT GUIDANCE IS SHOWING WILL STALL OVER THE WESTERN END OF THE
STATE. THERE IS STILL SOME UNCERTAINTY WITH HOW STRONG THIS FRONT
WILL BE, BUT EXPECT ADDITIONAL SHOWERS AND ISOLATED THUNDERSTORMS
TO CONTINUE THROUGH THE FORECAST PERIOD MAINLY OVER THE WESTERN
WATERS. GENTLE TO LOCALLY FRESH SOUTHERLY WINDS ARE EXPECTED
SUNDAY THROUGH THE FORECAST PERIOD AS THE SURFACE LOW DEVELOPS
NORTHWEST OF THE ISLANDS.
THE CURRENT NORTH SWELL HAS DECLINED OVERNIGHT AND WILL PLATEAU
AT MODERATE LEVELS THROUGH THE WEEKEND. A NEW MODERATE MEDIUM TO
LONG PERIOD NORTHWEST SWELL IS EXPECTED TO FILL IN LATE TONIGHT
AND PEAK SUNDAY NEAR OR AT HIGH SURF ADVISORY LEVEL CRITERIA FOR
NORTH AND WEST FACING SHORES BEFORE GRADUALLY DECLINING MONDAY. A
COMBINATION OF MODERATE NORTHWEST AND NORTH SWELLS WILL KEEP SURF
ELEVATED THROUGH THE FIRST HALF OF NEXT WEEK.
EAST FACING SHORES WILL REMAIN TINY TO SMALL GIVEN THE LACK OF
TRADE WINDS BUT SHORELINES EXPOSED TO THE NORTH SWELLS MAY BE
SLIGHTLY ELEVATED THROUGH WEDNESDAY. SURF ALONG SOUTH FACING
SHORES WILL SEE AN INCREASE OF SHORT PERIOD WIND WAVE CHOP MAINLY
OVER THE WESTERN ISLANDS THIS WEEKEND ASSOCIATED WITH THE PASSING
FRONT. A SLIGHT LULL IS EXPECTED SUNDAY BEFORE THE NEXT FRONT
APPROACHES AND INCREASES THE WIND WAVES COMING FROM THE SOUTH.
FIRE WEATHER
CONDITIONS WILL REMAIN BELOW CRITICAL FIRE WEATHER THRESHOLDS
THROUGH THE FORECAST PERIOD. WINDS ARE EXPECTED TO REMAIN LIGHT TO
MODERATE, WITH RELATIVE HUMIDITY STEADILY INCREASING AS A FRONT
APPROACHES FROM THE NORTHWEST LATE SATURDAY, THEN STALLS OVER THE
WESTERN END OF THE STATE SUNDAY AND MONDAY. ADDITIONAL SHOWERS
CHANCES EXPECTED MID TO LATE NEXT WEEK AS ANOTHER FRONT
APPROACHES, THEN STALLS ACROSS THE WESTERN HALF OF THE STATE.
HFO WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH FROM LATE TONIGHT THROUGH LATE MONDAY NIGHT FOR
NIIHAU-KAUAI LEEWARD-KAUAI MOUNTAINS-WAIANAE COAST-OAHU NORTH
SHORE-OLOMANA-CENTRAL OAHU-WAIANAE MOUNTAINS-KAUAI NORTH-KAUAI
EAST-KAUAI SOUTH-EAST HONOLULU-HONOLULU METRO-EWA PLAIN-KOOLAU
WINDWARD-KOOLAU LEEWARD.
SMALL CRAFT ADVISORY UNTIL 6 AM HST SUNDAY FOR KAUAI NORTHWEST
WATERS-KAUAI WINDWARD WATERS-KAUAI LEEWARD WATERS.
DISCUSSION...M BALLARD
AVIATION...M BALLARD
MARINE...SHIGESATO
FIRE WEATHER...M BALLARD
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