659
FXHW60 PHFO 081343
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
343 AM HST MON SEP 8 2025
SYNOPSIS
DRIER AIR MOVING INTO THE STABLE, LIGHT TO MODERATE TRADE WIND
FLOW OVER THE ISLANDS WILL LIMIT SHOWER ACTIVITY ON MOST ISLANDS.
HURRICANE KIKO IS FORECAST TO PASS NORTH OF THE ISLAND CHAIN
TUESDAY AND WEDNESDAY, DISRUPTING THE TRADE WINDS, PRODUCING
INCREASED HUMIDITY WITH AREAS OF HEAVY RAINFALL, AND GENERATING
LARGE SURF ALONG EAST FACING SHORES.
DISCUSSION
NO CHANGES TO THE FIRST FEW DAYS OF THE FORECAST, WITH ONLY MINOR
CHANGES IN THE FORECAST BEYOND THAT. SATELLITE DERIVED
PRECIPITABLE WATER IMAGERY SHOWS A DRIER SLOT OF AIR MOVING OVER
THE ISLANDS THIS MORNING. THIS DRIER AIR WILL HELP TO LIMIT SHOWER
ACTIVITY TODAY.
A TROUGH TO THE NORTHWEST OF THE ISLANDS CONTINUES TO MOVE WEST
AWAY FROM THE ISLANDS. THIS WILL ALLOW A BIT OF AN UPTICK IN WIND
SPEEDS TODAY, HOWEVER SOME LOCALIZED LAND AND SEA BREEZES WILL
REMAIN A POSSIBILITY. HURRICANE KIKO IS ABOUT 425 MILES EAST OF
HILO THIS MORNING, AND IS MOVING TO THE NORTHWEST. TOWARDS
SUNSET, MOISTURE ALONG THE WESTERN FLANK OF WEAKENING KIKO WILL
NEAR THE WINDWARD COASTS OF THE BIG ISLAND AND MAUI.
THE LATEST NATIONAL HURRICANE CENTER FORECASTS CONTINUE TO SHOW
KIKO WEAKENING TO A TROPICAL STORM AS IT PASSES NORTH OF THE
ISLANDS TUESDAY AND WEDNESDAY. CONFIDENCE IN THIS SCENARIO IS
INCREASING, THOUGH INTERESTS IN HAWAII SHOULD CONTINUE TO MONITOR
OFFICIAL FORECASTS FOR KIKO. MOISTURE ALONG THE PERIPHERY OF THE
SYSTEM WILL SPREAD OVER THE STATE MONDAY NIGHT AND TUESDAY.
INITIALLY, THIS WILL PROVIDE AN INCREASE IN CLOUDS AND MAINLY
WINDWARD SHOWERS, BUT AS TRADE WINDS BECOME DISRUPTED, AFTERNOON
SEA BREEZES WILL LIKELY TRIGGER SPOTTY INTERIOR RAINFALL. THESE
SHOWERS COULD BE LOCALLY HEAVY IN PLACES, AND WE CANNOT RULE OUT A
BRIEF THUNDERSTORM AS THE ATMOSPHERE DESTABILIZES ON TUESDAY. AS
DEW POINTS CREEP INTO THE LOW TO MID 70S, RATHER HUMID CONDITIONS
WILL PREVAIL. IN ADDITION, LARGE SURF WILL AFFECT EAST FACING
SHORES, AND SEE THE MARINE SECTION OF THIS DISCUSSION FOR MORE
DETAILS.
AS KIKO MOVES OFF TO THE NORTHWEST OF THE STATE ON WEDNESDAY
NIGHT AND THURSDAY, MODERATE TRADE WINDS AND A RIDGE ALOFT ARE
EXPECTED TO BUILD IN FROM THE EAST. THE RESULTING STABLE
CONDITIONS WILL BRING A DRIER AIR MASS WITH A TYPICAL PATTERN OF
WINDWARD RAINFALL AND DEW POINTS DROPPING BACK INTO THE MID 60S.
AVIATION
LIGHT TO MODERATE TRADES EXPECTED TODAY WITH LOCALIZED LAND/SEA
BREEZES. AN INCREASE IN CLDS AND SHRA IS EXPECTED THIS AFTERNOON.
MVFR CONDS POSSIBLE IN SHRA. VFR SHOULD PREVAIL OTHERWISE.
TROPICAL CYCLONE KIKO WILL APPROACH THE ISLANDS FROM THE
SOUTHEAST OVER THE NEXT FEW DAYS. THE NATIONAL HURRICANE CENTER
IS CURRENTLY FORECASTING KIKO TO PASS NORTH OF THE ISLANDS ON
TUESDAY. ANY DEVIATION SOUTH OF THIS FORECAST TRACK MAY RESULT IN
WIND AND RAIN IMPACTS TO THE STATE.
AIRMET SIERRA FOR MTN OBSC IS IN EFFECT FOR OAHU. CONDS SHOULD
IMPROVE BY MID-MORNING. AIRMET SIERRA MAY BE NEEDED THIS AFTERNOON
AND EVENING FOR MTN OBSC AS MOISTURE FROM TROPICAL CYCLONE KIKO
MOVES INTO THE AREA.
MARINE
A WEAK TROUGH NORTHWEST OF THE STATE WILL CONTINUE TO DRIFT
WESTWARD, AWAY FROM THE STATE TODAY. A BRIEF STINT OF MODERATE TO
LOCALLY FRESH TRADE WINDS ARE EXPECTED THROUGH TONIGHT.
HURRICANE KIKO, WHICH WAS LOCATED APPROXIMATELY 375 NM E OF HILO
THIS MORNING CONTINUES TO TRACK WEST- NORTHWEST IN THE CENTRAL
PACIFIC. ACCORDING TO THE LATEST FORECAST FROM THE NATIONAL
HURRICANE CENTER, KIKO IS EXPECTED TO ENTER THE EASTERN OFFSHORE
WATERS THIS EVENING AS A TROPICAL STORM. KIKO WILL THEN CONTINUE
TO WEAKEN AND MOVE WEST-NORTHWEST THROUGH THE OFFSHORE WATERS. A
TROPICAL STORM WARNING IS IN EFFECT FOR THE OFFSHORE WATERS WITH
TROPICAL STORM CONDITIONS EXPECTED OVER THE E AND NE OFFSHORE
WATERS TONIGHT THROUGH WEDNESDAY. THE LATEST FORECAST FOR THE
COASTAL WATERS, SHOWS STRONG CONFIDENCE FOR KIKO TO STAY NORTH OF
THE COASTAL WATERS. ALTHOUGH NO WIND IMPACTS ARE EXPECTED OVER THE
COASTAL WATERS, A QUICK RISE OF WAVE HEIGHTS ARE EXPECTED TONIGHT
INTO TUESDAY AS KIKO PASSES.
SURF ALONG EAST FACING SHORES WILL SLOWLY RISE TODAY AS SWELL
ENERGY FROM TROPICAL CYCLONE KIKO ARRIVES. LATEST BUOY
OBSERVATIONS FROM BUOY 51004 HAS STARTED TO PICK UP ENERGY IN THE
11 TO 13 SECOND SPECTRAL BANDS THROUGHOUT THE NIGHT. SURF WILL
LIKELY COME IN BELOW ADVISORY THRESHOLDS THROUGH TODAY. BUT, AS
KIKO MOVES NORTHWEST, A RAPID RISE OF A SHORT LIVED EAST SWELL IS
EXPECTED TO FILL IN, PEAK POTENTIALLY AT LOW END HIGH SURF WARNING
LEVELS TUESDAY, BEFORE DECLINING THROUGH WEDNESDAY. A HIGH SURF
WARNING FOR EAST FACING SHORES WILL LIKELY BE ISSUED THIS
AFTERNOON. NOTE, PEAK SURF HEIGHTS WILL BE HIGHLY DEPENDENT ON
THE TRACK AND INTENSITY OF KIKO AS IT NEARS THE STATE.
A MODERATE LONG PERIOD SOUTH-SOUTHWEST SWELL HAS FILLED IN
OVERNIGHT, LIKELY PEAK THIS MORNING AND WILL SLOWLY DECLINE THIS
AFTERNOON BEFORE ANOTHER REINFORCING SWELL OUT OF THE SOUTH-
SOUTHWEST IS EXPECTED ON TUESDAY. THIS SHOULD HELP MAINTAIN SURF
NEAR OR SLIGHTLY ABOVE THE SUMMER AVERAGE THROUGHOUT THE FIRST
HALF OF THE WEEK. ADDITIONALLY, MULTIPLE SMALL PULES OF NORTHWEST
SWELL ENERGY WILL GENERATE SMALL SURF ALONG NORTH FACING BEACHES
THROUGHOUT THE WEEK.
FIRE WEATHER
WINDS ARE FORECAST TO REMAIN BELOW CRITICAL FIRE WEATHER
THRESHOLDS FOR THE NEXT FEW DAYS. A NARROW SLOT OF VERY DRY AND
STABLE AIR WILL MOVE OVER THE ISLANDS FROM EAST TO WEST ON THE
WEAK TRADE WIND FLOW TODAY. THIS COULD PUSH THE INVERSION DOWN TO
AROUND 4,000 FEET AND PRODUCE VERY LOW HUMIDITY AT HIGHER
ELEVATIONS OF THE KAALA FIRE IN THE HAMAKUA DISTRICT OF THE BIG
ISLAND. INCREASED HUMIDITY AND HIGHER CHANCES FOR RAINFALL ARE
EXPECTED MONDAY NIGHT INTO WEDNESDAY AND TROPICAL CYCLONE KIKO
PASSES NORTH OF THE STATE.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...M BALLARD
AVIATION...WALSH
MARINE...SHIGESATO
FIRE WEATHER...M BALLARD
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