413
FXHW60 PHFO 110115
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
315 PM HST SAT JAN 10 2026
SYNOPSIS
STABLE AND MOSTLY DRY CONDITIONS ARE ACCOMPANIED BY LIGHT WINDS
THROUGH SUNDAY. A QUICK-MOVING COLD FRONT THEN BRINGS A QUICK HIT
OF SHOWERS TO THE ISLANDS LATE SUNDAY NIGHT INTO MONDAY. A SECOND
FRONT WILL BRING ANOTHER ROUND OF SHOWERS WEDNESDAY NIGHT INTO
THURSDAY WITH INCREASED POTENTIAL FOR HEAVY RAINFALL AROUND KAUAI
DURING WEDNESDAY.
DISCUSSION
POSITIVELY TILTED RIDGE WILL AMPLIFY OVER THE STATE THROUGH TONIGHT
ALLOWING SURFACE HIGH PRESSURE AND MODERATE SE WINDS TO BUILD OVER
THE EASTERN END OF THE STATE FOR SUNDAY. THE GRADIENT OVER OAHU AND
KAUAI TRANSITIONS TO LIGHT SW BUT LIKELY REMAINS LIGHT ENOUGH TO
SUPPORT ANOTHER DAY OF EXPANDING SEA BREEZES AND A FEW AFTERNOON
SHOWERS OVER THE INTERIOR.
A SHALLOW COLD FRONT WITH CLOUD TOPS GENERALLY 10KFT OR LESS IS
NOTED ON VISIBLE IMAGERY OVER AND EAST OF MIDWAY ATOLL. AHEAD OF IT,
LOW AND MID-LEVEL MOISTURE LINGERS IN THE FORM OF DISORGANIZED
SHOWERY CLOUDS. AN UPPER WAVE ONLY JUST BEGINNING TO DEEPEN OVER THE
NORTH PACIFIC WEST OF THE DATELINE IS SEEN ON WATER VAPOR AND IS
HANDLED WELL BY THE GUIDANCE. THIS WAVE WILL UNDERGO SUBSTANTIAL
AMPLIFICATION THROUGH MONDAY, THE ATTENDANT UPPER JET COUPLING WITH
THE AFOREMENTIONED FRONT AS DEEP LAYER ASCENT INCREASES. COMBINED
WITH AN INFLUX OF PREFRONTAL MOISTURE, THE FRONTAL CIRCULATION WILL
DEEPEN CONSIDERABLY AS CLOUD TOPS GROW TO AT LEAST 15-20KFT
SUPPORTING HEAVIER SHOWER DEVELOPMENT. THE MATURE JET-FRONT SYSTEM
REACHES KAUAI LATE SUNDAY NIGHT BRINGING A QUICK HIT OF SHOWERS,
SOME OF WHICH MAY BE HEAVY ALONG WEST AND NORTH FACING SLOPES. THE
FRONT THEN RAPIDLY WEAKENS AND SHALLOWS AS DYNAMICS DEPART TO THE
NE. INTENSITY WILL TREND STEADILY DOWNWARD AS HEIGHT FALLS AND
STRONG NW FLOW USHERS IT EASTWARD ACROSS THE STATE DURING MONDAY.
LEADING SW FLOW WILL STEER THE OCCASIONAL SHOWER OVER LEEWARD
PORTIONS OF THE SMALLER ISLANDS PRIOR TO THE FRONTAL PASSAGE. DRY
AND STRONGLY SUBSIDENT NW FLOW FILLS IN BEHIND THE FRONT RESULTING
IN A RAPID TRANSITION TO A HIGH STABILITY POST-FRONTAL ENVIRONMENT
AS DEWPOINTS CRASH WELL INTO THE 50S. LOWS OVER THE WESTERN END OF
THE STATE LIKELY FALL INTO THE LOW 60S WITH SHELTERED AND INTERIOR
LOCALES DIPPING INTO THE 50S BY TUESDAY MORNING. LIGHT TO MODERATE
TRADES AND DRY/LOW DEWPOINT WEATHER PREVAILS ON TUESDAY.
BY TUESDAY NIGHT, THE NEXT WAVE IN THE SEQUENCE APPROACHES THE
FORECAST AREA. VEERING WINDS WILL CAUSE THE REMNANTS OF MONDAY'S
FRONT TO LIFT NORTHWARD PROVIDING SUBSTANTIALLY MORE PREFRONTAL
MOISTURE THIS TIME AROUND. LEEWARD LOCATIONS WILL LIKELY SEE A
GREATER COVERAGE OF SHOWERS WITHIN PREVAILING SW FLOW LATE TUESDAY
NIGHT AND POTENTIALLY THROUGH WEDNESDAY. OF NOTE, THE EC AND GFS
BOTH ALLOW FRONTAL REMNANTS TO ORGANIZE WITHIN CONVERGENT,
PREFRONTAL SW FLOW OVER KAUAI FOR ALL OF WEDNESDAY. THIS PERIOD WILL
BEAR WATCHING AS A FLOOD THREAT PERHAPS 12-18 HOURS IN DURATION
COULD MANIFEST FOR KAUAI DURING THIS TIME. THE FRONT ITSELF ARRIVES
WEDNESDAY NIGHT AND IS ALMOST INDISTINGUISHABLE FROM MONDAY'S
FRONTAL PASSAGE IN THAT IT WILL ARRIVE AS A STRONG, DYNAMICALLY
COUPLED FEATURE THAT WILL LOSE SUPPORT AND WEAKEN AS IT ADVANCES
EASTWARD. SIMILARLY, DEWPOINTS ONCE AGAIN FALL INTO THE 50S IN ITS
WAKE AS BREEZY POST-FRONTAL NW WINDS VEER TO TRADES BY THURSDAY
NIGHT.
AVIATION
LIGHT BACKGROUND WINDS HAVE RESULTED IN DAYTIME SEA BREEZES
ACROSS THE ISLAND CHAIN TODAY, INCREASING CLOUD COVER AND
PRODUCING A FEW SHOWERS OVER THE ISLANDS. ANY REMAINING SHOWERS
SHOULD DIMINISH THIS EVENING WITH THE LOSS OF DIURNAL HEATING AND
THE DEVELOPMENT OF THE OFFSHORE LAND BREEZES.
LITTLE CHANGE IS EXPECTED INTO SUNDAY, WITH DAYTIME SEA BREEZES
DEVELOPING AND INCREASING CLOUDS OVER THE ISLANDS ONCE AGAIN. VFR
FLIGHT CONDITIONS ARE ANTICIPATED TO PREVAIL OVER MOST LOCATIONS
THROUGHOUT THE NEXT 24 HOURS.
A FRONT WILL ARRIVE BY SUNDAY NIGHT, AND SHOWERS ARE EXPECTED
FROM SUNDAY NIGHT THROUGH MONDAY ALONG THE FRONTAL BOUNDARY AS IT
MOVES DOWN THE ISLAND CHAIN. AHEAD OF THE FRONT, LIGHT SOUTHERLY
WINDS WILL PREVAIL, BUT AS THE FRONT PASSES, WINDS WILL SWITCH TO
BECOME NORTHERLY AND INCREASE TO MODERATE LEVELS.
THERE ARE NO AIRMETS CURRENTLY IN EFFECT, AND NONE ARE
ANTICIPATED THROUGH TONIGHT.
MARINE
A WEAK HIGH PRESSURE RIDGE WILL REMAIN NEARLY STATIONARY OVER THE
CENTRAL WATERS THIS WEEKEND. A COLD FRONT WILL SWEEP FROM WEST TO
EAST DOWN THE ISLAND CHAIN ON MONDAY, STALLING NEAR THE BIG
ISLAND BY MONDAY NIGHT. AN EVEN STRONGER COLD FRONT WILL QUICKLY
MOVE THROUGH THE ISLANDS, SPREADING STRONG TO NEAR GALE FORCE
WINDS ACROSS THE NORTHWESTERN COASTAL WATERS LATE NEXT WEEK FROM
WEDNESDAY INTO THURSDAY. A SMALL CRAFT ADVISORY IS IN EFFECT FOR
HAWAIIAN COASTAL WATERS EXPOSED TO THE LARGE NORTHWEST SWELL,
THESE ELEVATED SEAS ABOVE 10 FEET ARE FORECAST TO LAST IN SUNDAY
FOR WATERS AND CHANNELS EXPOSED TO THE NORTHWEST SWELL.
A HIGH SURF ADVISORY (HSA) IS IN EFFECT THROUGH SUNDAY FOR
EXPOSED NORTH AND WEST FACING SHORES. NEAR SHORE BUOYS SHOW A
A HEIGHT AND PERIOD UPWARD SPIKE AS THE NEW SWELL ARRIVED. THIS
SWELL WILL PEAK TONIGHT AND HOLD ABOVE HSA THRESHOLDS INTO MONDAY
AS ANOTHER MUCH LARGER OVERLAPPING NORTHWEST (320-330 DEGREE)
SWELL SWIFTLY BUILDS SURF TO HIGH SURF WARNING LEVELS POTENTIALLY
FROM MONDAY THROUGH TUESDAY. YET ANOTHER XL SWELL WILL BUILD INTO
THE ISLANDS BY LATE THURSDAY, POTENTIALLY PRODUCING ANOTHER ROUND
OF WARNING LEVEL SURF ALONG EXPOSED NORTH AND WEST FACING SHORES.
SURF ALONG EAST FACING SHORES WILL REMAIN SMALL THROUGH THE WEEKEND
AS WINDS OVER AND UPWIND OF HAWAII REMAIN WEAK. SOME INCREASE IN EAST
SHORE SURF IS POSSIBLE EARLY NEXT WEEK AS A COLD FRONT MOVES DOWN THE
ISLAND CHAIN. ALONG SOUTH SHORES, SURF WILL REMAIN VERY SMALL THROUGH
THE FORECAST PERIOD.
HFO WATCHES/WARNINGS/ADVISORIES
HIGH SURF ADVISORY UNTIL 6 PM HST SUNDAY FOR NIIHAU-WAIANAE
COAST-OAHU NORTH SHORE-MAUI WINDWARD WEST-KAUAI NORTH-KAUAI EAST-
MOLOKAI WINDWARD-MOLOKAI NORTH-MOLOKAI WEST-MAUI CENTRAL VALLEY
NORTH-WINDWARD HALEAKALA.
SMALL CRAFT ADVISORY UNTIL 6 PM HST SUNDAY FOR KAUAI NORTHWEST
WATERS-KAUAI WINDWARD WATERS-KAUAI LEEWARD WATERS-KAUAI CHANNEL-
OAHU WINDWARD WATERS-KAIWI CHANNEL-MAUI COUNTY WINDWARD WATERS-
ALENUIHAHA CHANNEL-BIG ISLAND WINDWARD WATERS.
DISCUSSION...JVC
AVIATION...VAUGHAN
MARINE...FOSTER
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