675
FXHW60 PHFO 210113
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
313 PM HST WED AUG 20 2025
SYNOPSIS
MODERATE TO LOCALLY BREEZY TRADE WINDS WILL PERSIST THROUGH AT
LEAST THE WEEKEND AS HIGH PRESSURE HOLDS NORTH OF THE ISLANDS.
TYPICAL STABLE SUMMERTIME CONDITIONS WILL BRING PERIODS OF MAINLY
WINDWARD AND MAUKA SHOWERS, WHILE MOST LEEWARD AREAS REMAIN RATHER
DRY.
DISCUSSION
A LOCALLY BREEZY AND STABLE TRADE WIND FLOW CONTINUES. THE TRADES
ARE BEING DRIVEN BY BROAD SURFACE HIGH PRESSURE FAR NORTH AND
NORTHEAST OF THE STATE, WHILE A MID-LEVEL RIDGE IS MAINTAINING
STABLE CONDITIONS WITH AN INVERSION BASED BETWEEN 5,000 AND 7.000
FT. A SHALLOW BAND OF MOISTURE TRAVELING WITHIN THE STABLE TRADE
WIND FLOW MOVED ACROSS ALL ISLANDS EXCEPT KAUAI TODAY, DROPPING UP
TO A QUARTER OF AN INCH OF RAINFALL ALONG WINDWARD SLOPES AS WELL
AS A FEW HUNDREDTHS ON THE BURN AREA OF THE KUNIA CAMP FIRE.
ANOTHER BATCH OF SHALLOW MOISTURE WILL MOVE ONTO WINDWARD BIG
ISLAND AND MAUI OVERNIGHT, THEN PASS OVER THE WESTERN HALF OF THE
ISLAND CHAIN ON THURSDAY. WE ARE NOT EXPECTING SIGNIFICANT
WINDWARD RAINFALL, AND WITH THE EXCEPTION OF AFTERNOON SHOWERS
ACROSS THE KONA DISTRICTS OF THE BIG ISLAND, LEEWARD AREAS SHOULD
REMAIN RATHER DRY. IN ADDITION, THIN HIGH CLOUDS WILL LINGER
OVERHEAD INTO TONIGHT, ADDING SOME COLOR TO THE SUNSET.
LITTLE CHANGE TO THE TYPICAL MID AUGUST WEATHER PATTERN IS
EXPECTED THROUGH THE WEEKEND, FOLLOWED BY A POSSIBLE SLIGHT
DECLINE IN WINDS LATE SUNDAY INTO TUESDAY. A PERSISTENT MID-LEVEL
RIDGE WILL MAINTAIN STABILITY, AND LITTLE ORGANIZED MOISTURE IS
SEEN IN THE GUIDANCE UNTIL TUESDAY. AS A RESULT, EXPECT LIMITED
WINDWARD RAINFALL, AND WITH THE EXCEPTION OF THE KONA SLOPES OF
THE BIG ISLAND, MOST LEEWARD AREAS WILL REMAIN RATHER DRY.
AVIATION
MODERATE TO LOCALLY BREEZY TRADES WILL PERSIST THROUGH THE NEXT
SEVERAL DAYS, FOCUSING LOW CLOUDS AND SHOWERS OVER WINDWARD AND
MOUNTAIN AREAS, PARTICULARLY OVERNIGHT INTO THE MORNING HOURS.
MVFR CONDITIONS WILL BE POSSIBLE IN SHOWERS, OTHERWISE VFR WILL
LIKELY PREVAIL.
NO AIRMETS ARE CURRENTLY IN EFFECT.
MARINE
HIGH PRESSURE WILL MAINTAIN FRESH TO LOCALLY STRONG
TRADE WINDS ACROSS HAWAIIAN COASTAL WATERS THROUGHOUT THE NEXT
SEVERAL DAYS. BASED ON THE LATEST GUIDANCE, THE SMALL CRAFT
ADVISORY (SCA) THAT IS IN EFFECT FOR THE WINDIER WATERS AND
CHANNELS OF MAUI COUNTY AND THE BIG ISLAND HAS BEEN EXTENDED IN
TIME THROUGH SATURDAY.
A SERIES OF SMALL, MEDIUM PERIOD SOUTH (170-190 DEGREE) SWELLS
IS EXPECTED THROUGHOUT THE REST OF THIS WEEK, WITH SURF NEAR THE
SUMMERTIME AVERAGE THROUGH AROUND SATURDAY ALONG SOUTH-FACING
SHORES. THE LARGEST OF THESE SOUTH SWELLS LOOKS TO ARRIVE THURSDAY
INTO FRIDAY. SURF HEIGHTS SHOULD DECREASE SUNDAY INTO EARLY NEXT
WEEK AS THESE SWELLS FADE. ANOTHER SMALL, LONG PERIOD SOUTH SWELL
COULD ARRIVE BY THE MIDDLE OF NEXT WEEK.
CHOPPY CONDITIONS WILL CONTINUE FOR EAST-FACING SHORES THROUGH
THE FORECAST PERIOD DUE TO THE PERSISTENT FRESH TRADES. SURF ALONG
NORTH FACING SHORES WILL REMAIN NEARLY FLAT THROUGH THE NEXT WEEK.
PEAK HIGH TIDES ASSOCIATED WITH THE LUNAR CYCLE WILL LEAD TO MINOR
COASTAL FLOODING ALONG SHORELINES AND LOW LYING COASTAL AREAS
DURING THE AFTERNOON HIGH TIDES THROUGH THURSDAY AFTERNOON. A
COASTAL FLOOD STATEMENT REMAINS IN EFFECT FOR MINOR COASTAL
FLOODING.
FIRE WEATHER
TRADE WINDS WILL REMAIN IN THE MODERATE TO LOCALLY BREEZY RANGE
INTO SUNDAY WHILE A RIDGE ALOFT MAINTAINS AN INVERSION BETWEEN
5,500 TO 7,000 FT. UNDER THIS RATHER TYPICAL AUGUST WEATHER
PATTERN, AFTERNOON RELATIVE HUMIDITY SHOULD REMAIN NEAR
SUMMERTIME AVERAGE ON THURSDAY. SLIGHTLY DRIER CONDITIONS ARE
POSSIBLE FRIDAY INTO THE WEEKEND. AS A RESULT, NEAR CRITICAL FIRE
WEATHER CONDITIONS ARE EXPECTED, THOUGH WE DO NOT ANTICIPATE FIRE
WEATHER HEADLINES AT THIS TIME.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 PM HST SATURDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.
DISCUSSION...WROE
AVIATION...FARRIS
MARINE...VAUGHAN
FIRE WEATHER...WROE
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