489
FXHW60 PHFO 201508
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
508 AM HST THU AUG 20 2026
SYNOPSIS
INCREASED SHOWER ACTIVITY IS EXPECTED THROUGH FRIDAY AS TRADE
WINDS WEAKEN. WE'RE CONTINUING TO MONITOR TROPICAL DEPRESSION
TWO-C WHICH COULD STRENGTHEN INTO A TROPICAL CYCLONE WITH IMPACTS
TO THE STATE POSSIBLE LATE SATURDAY THROUGH LATE MONDAY. THERE
REMAINS UNCERTAINTY IN THE DETAILS OF THE FORECAST SO PLEASE
CONTINUE TO MONITOR IN THE COMING DAYS FOR ADDITIONAL INFORMATION.
DISCUSSION
WEAK TRADE WINDS TODAY WILL ALLOW FOR A SEA BREEZE TO DEVELOP,
INCREASING CHANCES OF SHOWERS IN SOME LEEWARD AREAS. WINDS WILL
INCREASE LATE FRIDAY AND VEER EASTERLY. TYPICAL TRADE SHOWERS WILL
RETURN OVER WINDWARD AND MAUKA AREAS, MOST COMMON AT NIGHT. FORECAST
FOR SATURDAY WILL BE INFLUENCED BY HOW THE TROPICAL SYSTEM TO THE
EAST-SOUTHEAST OF THE STATE EVOLVES. CURRENT FORECAST MAINTAINS
TYPICAL TRADE WIND SHOWERS AND INCREASING WINDS.
TROPICAL DEPRESSION TWO-C HAS DEVELOPED 960 MILES EAST-SOUTHEAST OF
HILO. THE FIRST LOOK AT THE POTENTIAL TRACK KEEPS THE STORM SOUTH OF
THE BIG ISLAND, BUT IT IS STILL EARLY IN THE FORECAST PROCESS AND
THE TRACK COULD SHIFT EITHER NORTH OR SOUTH IN COMING ADVISORY
CYCLES. IMPACTS FROM RAIN, WIND, AND SURF CAN BE EXPERIENCED WELL
OUTSIDE THE CENTER OF THE STORM SO DO NOT FOCUS TOO MUCH ON THE
EXACT TRACK. CURRENT GUIDANCE INDICATES THAT PRECIPITATION WILL
INCREASE ON THE EAST SIDE OF THE STATE SATURDAY NIGHT INTO SUNDAY,
SPREADING WEST SUNDAY NIGHT INTO MONDAY. THE TIMING, DIRECTION, AND
MAGNITUDE OF THE STRONGEST WINDS REMAIN HIGHLY DEPENDENT ON THE
TRACK AND INTENSITY OF THE SYSTEM.
IN ANTICIPATION OF CRITICAL NEW UPDATES WITH EACH OF THE ADVISORY
PACKAGES ISSUED BY THE NATIONAL HURRICANE CENTER (NHC), NWS HONOLULU
WILL DELAY THE ISSUANCES OF OUR TYPICAL FORECAST PACKAGE PRODUCTS
(AFD, SFT, PFM, ZFP, SRF, CWF, ETC) UNTIL AFTER THE RELEASE OF NHC'S
SUITE OF PRODUCTS, TO INCORPORATE THE LATEST AND MOST UP-TO-DATE
INFORMATION ON TROPICAL DEPRESSION TWO-C.
AVIATION
A SURFACE TROUGH PASSING OVER THE ISLANDS WILL WEAKEN WINDS
ALLOWING FOR SEA/LAND BREEZE DEVELOPMENT. AFTERNOON SHRA ARE
POSSIBLE OVER LEEWARD AND INTERIOR AREAS WITH ISOL SHRA OVER MAUKA
AND WINDWARD SPOTS OVERNIGHT. MVFR CONDS CAN BE EXPECTED IN SHRA,
OTHERWISE VFR PREVAILS.
NO AIRMETS ARE CURRENTLY IN EFFECT.
MARINE
HIGH PRESSURE TO THE FAR NORTHEAST WILL GRADUALLY WEAKEN OVER
THE NEXT COUPLE OF DAYS. ADDITIONALLY, A TROUGH NORTHEAST OF THE
ISLANDS WILL TRACK NORTHWESTWARD ACROSS THE OFFSHORE WATERS,
LEADING TO A PERIOD OF LIGHT AND VARIABLE WINDS TODAY FOR MOST
WATERS, ALLOWING DAYTIME SEA BREEZES AND OVERNIGHT LAND BREEZES
TO BECOME ESTABLISHED. BY LATE FRIDAY, MODERATE TO LOCALLY FRESH
TRADES WILL BEGIN TO BUILD BACK INTO THE REGION AS THE TROUGH
EXITS TO THE NORTHWEST, HIGH PRESSURE DRIFTS SOUTHWARD CLOSER TO
THE ISLAND CHAIN, AND NEWLY DEVELOPED TROPICAL DEPRESSION TWO-C
NEARS THE STATE FROM THE SOUTHEAST. THE FORECAST FOR THIS WEEKEND
WILL DEPEND SIGNIFICANTLY ON THE UNCERTAIN TRACK OF THIS TROPICAL
CYCLONE.
SURF ALONG SOUTH FACING SHORES WILL REMAIN SLIGHTLY BELOW AVERAGE
THROUGH THURSDAY. A LONG PERIOD SOUTH-SOUTHWEST SWELL GENERATED FROM
GALES JUST SOUTH AND EAST OF NEW ZEALAND WILL BEGIN ARRIVING LATE
THURSDAY INTO FRIDAY, BOOSTING SURF TO NEAR AVERAGE BY FRIDAY NIGHT.
SURF ALONG EAST FACING SHORES ALSO REMAINS BELOW AVERAGE WITH WEAK
TRADES, THEN BUILDS THIS WEEKEND AS THE TRADES RESTRENGTHEN. THIS WILL
BE COMPOUNDED BY A SOUTHEAST SWELL GENERATED BY TROPICAL DEPRESSION
TWO-C THAT WILL BUILD THROUGH SUNDAY AND COULD APPROACH ADVISORY
LEVELS. NORTH FACING SHORES WILL REMAIN TINY THROUGH FRIDAY, WITH
A SLIGHT BUMP FROM LALA SWELL (290 TO 300 DEGREES) POSSIBLE THIS
WEEKEND.
FIRE WEATHER
ISSUED AT 504 AM HST THU AUG 20 2026
TRADE WINDS WILL WEAKEN TODAY, INCREASING CHANCES OF SHOWERS
FOR THE LEEWARD SIDE OF THE ISLANDS. TRADE WINDS INCREASE OVER THE
WEEKEND WITH SHOWERS SWITCHING TO WINDWARD. THE INVERSION IS 6000 TO
7000 FT. INCREASED WIND AND RAIN POSSIBLE ACROSS THE STATE LATE
IN THE WEEKEND INTO EARLY NEXT WEEK.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION/FIRE WEATHER...CO
AVIATION...WALSH
MARINE...QUESADA
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