025
FXHW60 PHFO 050128
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
328 PM HST TUE AUG 4 2026
SYNOPSIS
RELATIVELY WEAK TRADES WILL CONTINUE THROUGH FRIDAY, WITH
INCREASING WIND SPEEDS THIS WEEKEND. AN UPPER LOW AND MIDLEVEL
TROUGH WILL BRING AN INCREASED CHANCE OF SHOWERS TO THE WESTERN
END OF THE STATE OVER THE NEXT FEW DAYS. SHOWERS WILL SHIFT TO
THE EASTERN END OF THE STATE THIS WEEKEND AS AN AREA OF TROPICAL
MOISTURE PASSES BY.
DISCUSSION
AN UPPER LOW TO THE WEST AND ASSOCIATED MIDLEVEL TROUGH WILL
LINGER OVER THE NEXT COUPLE OF DAYS AND ENHANCE INCOMING TRADE
WIND SHOWERS, PARTICULARLY ACROSS THE WESTERN HALF OF THE STATE.
COOLING ALOFT ACROSS THE WEST HAS ERODED THE TRADE WIND INVERSION
WITH 00Z SOUNDINGS SHOW A WEAKER AND ELEVATED INVERSION AT LIHUE
COMPARED TO HILO. THE UPPER LOW IS FORECAST TO LIFT AWAY TO THE
NORTH ON FRIDAY RETURNING MORE STABLE CONDITIONS TO THE AREA.
TRADES WILL BE WEAKER THAN AVERAGE THROUGH THURSDAY AS THE REMNANT
OF FORMER TROPICAL CYCLONE GENEVIEVE LINGERS BETWEEN THE
SUBTROPICAL HIGH AND HAWAII. AS A RESULT, TRADES WILL BE WEAK AND
LOCALIZED SEA BREEZES WILL BRING INTERIOR AND LEEWARD CLOUD BUILD
UPS EACH AFTERNOON. ACROSS KAUAI AND OAHU, SCATTERED SHOWERS MAY
DEVELOP DURING THE AFTERNOONS DUE TO THE INSTABILITY AND LOW LEVEL
MOISTURE FROM THE UPPER LOW/TROUGH DESCRIBED EARLIER. TRADES WILL
INCREASE THIS WEEKEND, DOING AWAY WITH MOST OF THE SEA BREEZE
EFFECTS.
THE WEEKEND GUIDANCE SUGGESTS A PLUME OF MOISTURE COMING EITHER
OVER OR VERY CLOSE TO MAUI AND BIG ISLAND. WHILE MOST OF THE PLUME
WILL PASS SOUTH OF THE AREA, THE NORTHERN PERIPHERY OF IT IS
EXPECTED TO SKIRT BY AND BRING ADDITIONAL SHOWERS TO WINDWARD
SIDES OF BOTH ISLANDS.
AVIATION
A WEAK HIGH PRESSURE RIDGE FAR NORTH OF THE STATE WILL KEEP
GENTLE TRADE WINDS IN THE FORECAST. AN UPPER LEVEL LOW AND
ASSOICATED LOW LEVEL INVERTED TROUGH WILL REMAIN OVER THE WESTERN
END OF THE STATE, ENHANCING TRADE WIND SHOWERS. OTHERWISE HYBRID
PATTERN OF TRADE WIND CLOUDS AND SHOWERS WILL FOCUS OVER WINDWARD
AND MAUKA AREAS WITH AFTERNOON SEABREEZES INCREASING CLOUD AND
SHOWERS OVER LEEWARD AND INTERIOR AREAS. LAND BREEZES WILL CLEAR
CLOUDS AND SHOWERS OVERNIGHT FOR THE SHELTERED AREAS.
AIRMET SIERRA IN EFFECT FOR MOUNTAIN OBSCURATION ABOVE 020 FOR THE
ENTIRE ISLAND OF KAUAI AND FOR WINDWARD AND MAUKA AREAS OF OAHU
AND MOLOKAI. PERIODS OF MVFR CONDITIONS ARE POSSIBLE OVERNIGHT
FOR WINDWARD AND MAUKA AREAS FOR THE REST OF THE STATE. OTHERWISE
EXPECT MOSTLY VFR.
WILL CONTINUE TO MONITOR ALL OBSERVATIONS FOR POSSIBLE AIRMET
TANGO DUE TO UPPER LEVEL TURBULENCE AS THE UPPER LEVEL LOW AND
ASSOCIATED JET APPROACHES KAUAI FROM THE NORTHWEST. IN ADDITION
WILL ALSO KEEP MONITORING FOR POSSIBLE AIRMET ZULU DUE TO LIGHT
ICING ABOVE THE FREEZING LEVEL WITHIN THE UPPER LEVEL CLOUD BAND.
MARINE
NO SIGNIFICANT CHANGES TO THE FORECAST OR THE FORECAST PHILOSOPHY
WITH THE AFTERNOON PACKAGE. THE REMNANTS OF FORMER TROPICAL
CYCLONE GENEVIEVE ARE MORE THAN 900 MILES NORTHEAST OF THE ISLANDS
THIS AFTERNOON, AND CONTINUE TO LIFT NORTHWARD AND WEAKEN. A WEST
TO EAST ORIENTED FRONT REMAINS WELL NORTH OF THE ISLANDS. THESE
SYSTEMS ARE HELPING TO LIMIT TRADE WIND SPEEDS ACROSS THE ISLANDS.
AS THEY DISSIPATE AND MOVE AWAY FROM THE ISLANDS, HIGH PRESSURE
NORTH OF THE ISLANDS WILL HELP TRADES TO RESTRENGTHEN TO LOCALLY
BREEZY LEVELS BY THE END OF THE WEEK. THIS COULD THEN BRING SOME
SMALL CRAFT ADVISORY LEVEL WINDS TO THE MORE TYPICAL WINDIER AREAS
LATE IN THE WEEK OR OVER THE WEEKEND.
SURF ALONG SOUTH-FACING SHORES WILL REMAIN BELOW SEASONAL AVERAGES
THROUGH MUCH OF THIS WEEK, THOUGH OCCASIONAL SMALL FLUCTUATIONS
CAN BE EXPECTED AS SMALL BACKGROUND SWELLS MOVE THROUGH. BY THIS
SATURDAY, A SMALL, LONG PERIOD SOUTH SWELL IS EXPECTED TO ARRIVE,
FOLLOWED BY A SERIES OF REINFORCING SOUTH SWELLS THAT WILL BOOST
SURF HEIGHTS TO NEAR OR ABOVE SEASONAL AVERAGES INTO NEXT WEEK.
SMALL, MEDIUM PERIOD EASTERLY SWELL GENERATED FROM FORMER TROPICAL
CYCLONE GENEVIEVE CONTINUES TO LINGER, BUT WILL GRADUALLY EASE
FOR THE NEXT COUPLE OF DAYS. CHOPPY CONDITIONS WILL REMAIN, GENERATED
BY THE MODERATE TRADE WINDS.
SURF ALONG NORTH FACING AND WEST SHORES WILL REMAIN FLAT TO TINY
THROUGH THE FORECAST PERIOD, EXCEPT FOR AREAS EXPOSED TO THE EASTERLY
TRADE WRAP.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...FOSTER
AVIATION...ALMANZA
MARINE...M BALLARD
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