885
FXHW60 PHFO 060121
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
321 PM HST SUN JUL 5 2026
SYNOPSIS
HIGH PRESSURE TO THE NORTH WILL DRIVE BREEZY TRADE WINDS THIS
WEEK. SHOWER ACTIVITY WILL REMAIN LIMITED WITH A BRIEF INCREASING
TREND ON TUESDAY, AND AGAIN FROM THURSDAY THROUGH FRIDAY AS A
WEAK EASTERLY WAVE MOVES FROM EAST TO WEST ACROSS THE STATE. ANY
SHOWERS WILL THAT DEVELOP IN THIS TRADE WIND PATTERN WILL FAVOR
WINDWARD MOUNTAIN SLOPES OF EACH ISLAND DURING THE OVERNIGHT TO
EARLY MORNING HOURS.
DISCUSSION
THE SATELLITE IMAGERY THIS MORNING SHOWS A WEAK EASTERLY WAVE
NEAR 150W LONGITUDE RIDING THE EASTERLY TRADE WINDS TOWARDS THE
BIG ISLAND. THIS WEAK TROUGH WILL BRING A BRIEF PERIOD OF
INCREASING SHOWER TRENDS TO THE STATE ON TUESDAY. ANOTHER STRONGER
TROUGH CURRENTLY NEAR 130W LONGITUDE, LOOSELY ASSOCIATED WITH THE
REMNANTS OF FORMER TROPICAL CYCLONE DOUGLAS, WILL RIDE THE TRADE
WINDS INTO HAWAII FROM THURSDAY TO FRIDAY PRODUCING ANOTHER ROUND
OF SHOWERS SPREADING EAST TO WEST ACROSS THE STATE. RAINFALL
AMOUNTS WITH THIS FIRST SYSTEM WILL BE LIMITED DUE TO THE STABLE
RIDGE ALOFT, THE SECOND TROUGH WILL BRING SIGNIFICANT INCREASES TO
HUMIDITY LEVELS AND THE POTENTIAL FOR HIGHER RAINFALL AMOUNTS
FAVORING ISLAND MOUNTAIN SLOPES.
OTHERWISE, EASTERLY TRADE WINDS WILL CONTINUE THROUGH THE END OF
THIS WEEK AS THE SUBTROPICAL RIDGE REMAINS LOCKED IN PLACE NORTH
OF HAWAII. SUBTLE DAY TO DAY CHANGES TO THE TRADE WIND SPEEDS
SHOULD BE EXPECTED. MOSTLY STABLE WEATHER CONDITIONS ARE FORECAST
FOR THE NEXT SEVEN DAYS WITH SLIGHT INCREASES IN SHOWER ACTIVITY
ON TUESDAY, AND STRONGER RAINFALL TRENDS FROM THURSDAY THROUGH
FRIDAY AS TWO EASTERLY WAVES DRIFT THROUGH THE ISLAND CHAIN.
RAINFALL AMOUNTS OVER THE NEXT SEVEN DAYS WILL REMAIN LIMITED DUE
TO LARGE SCALE STABILITY, WITH THE HIGHEST AMOUNTS FORECAST DURING
THE THURSDAY TO FRIDAY TIME PERIOD.
AVIATION
MODERATE TO LOCALLY BREEZY TRADES WILL CONTINUE THROUGH MONDAY.
LOW CLOUDS AND SCATTERED SHOWERS WILL CONTINUE TO IMPACT WINDWARD
AND MOUNTAIN AREAS, WITH SOME SPILLOVER INTO LEEWARD SITES. VFR
CONDITIONS ARE BROADLY EXPECTED, WITH LOCALIZED MVFR MAINLY FOR
WINDWARD/MAUKA SITES.
AIRMET TANGO REMAINS IN EFFECT FOR MODERATE LOW LEVEL TURBULENCE
OVER AND DOWNWIND OF TERRAIN FOR ALL ISLANDS. THIS AIRMET WILL
LIKELY CONTINUE THROUGH THE NEXT SEVERAL DAYS.
MARINE
HIGH PRESSURE MAINTAINS FRESH TO LOCALLY STRONG TRADES THROUGH
THE WEEK. A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL LOCAL
WATERS.
A MODERATE, LONG PERIOD, SSW SWELL IS FILLING IN TODAY AND
BOOSTING SURF ALONG S SHORES TO JUST SHY OF THE ADVISORY
THRESHOLD. ENERGY ASSOCIATED WITH THIS SWELL IS SPREAD ACROSS THE
SPECTRUM AND NOT NECESSARILY FOCUSED IN THE LONG PERIOD BINS. THIS
INCREASES CONFIDENCE THAT AN ADVISORY WILL NOT BE NEEDED.
SURF ALONG E FACING SHORES WILL REMAIN CHOPPY THROUGH THE
WEEK AS FRESH TO LOCALLY STRONG TRADES HOLD. SURF ALONG N SHORES
REMAINS FLAT TO TINY.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 PM HST MONDAY FOR ALL HAWAIIAN
WATERS-
DISCUSSION...FOSTER
AVIATION...PARKER
MARINE...JVC
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