321
FXHW60 PHFO 051303
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
303 AM HST SUN JUL 5 2026
SYNOPSIS
A RIDGE OF HIGH PRESSURE WILL REMAIN ANCHORED IN PLACE NORTH OF
THE HAWAIIAN ISLANDS FOR THE FORESEEABLE FUTURE. EASTERLY TRADE
WINDS WILL CONTINUE TO BLOW ACROSS THE REGION THROUGH THE END OF
THIS WEEK. SHOWER ACTIVITY WILL REMAIN LIMITED WITH BRIEF
INCREASING TRENDS ON TUESDAY, AND STRONGER TRENDS 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, 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 THE
HOLIDAY WEEKEND, WITH A SLIGHT UPTICK IN SPEED EXPECTED THIS
AFTERNOON. LOW CLOUDS AND SHOWERS MAY CONTINUE TO IMPACT WINDWARD
AND MOUNTAIN AREAS AT TIMES THROUGHOUT THE PERIOD, WITH SOME
SPILLOVER SHOWERS INTO LEEWARD SITES POSSIBLE AS WELL, HOWEVER VFR
CONDITIONS ARE BROADLY EXPECTED, WITH LOCALIZED MVFR POSSIBLE
MAINLY FOR WINDWARD SITES.
AIRMET SIERRA IS IN EFFECT FOR MOUNTAIN OBSCURATION ACROSS
WINDWARD SECTIONS OF OAHU AND THE BIG ISLAND. THIS IS EXPECTED TO
PERSIST THROUGH THE EARLY MORNING, HOWEVER THE SPORADIC NATURE OF
SHOWER ACTIVITY MAY SHIFT HOW LONG THIS AIRMET IS IN EFFECT FOR.
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 WEEKEND.
MARINE
A HIGH PRESSURE RIDGE NORTH OF THE HAWAIIAN ISLANDS WILL REMAIN
NEARLY STATIONARY THIS WEEK AND HELP DRIVE MODERATE TO STRONG
TRADES ACROSS THE LOCAL WATERS. A SMALL CRAFT ADVISORY
(SCA), CURRENTLY IN EFFECT FOR THE TYPICAL WINDY WATERS AND
CHANNELS AROUND MAUI AND THE BIG ISLAND WILL BE EXPANDED BY MID
MORNING TO COVER ALL LOCAL HAWAIIAN WATERS. MODERATE TO LOCALLY
STRONG TRADES AND ACCOMPANYING SCAS WILL CONTINUE THROUGH THE
WEEK.
A NEW LONG PERIOD SOUTH-SOUTHWEST SWELL, ALREADY BEING REPORTED
AT THE NEAR SHORE BUOYS, WILL CONTINUE TO FILL IN TODAY. THIS
WILL BOOST SOUTH SHORE SURF HEIGHTS TO JUST SHY OF HIGH SURF
ADVISORY (HSA) LEVELS THROUGH MONDAY. IF THIS SWELL COMES IN MUCH
ABOVE GUIDANCE, A HSA WILL NEED TO BE ISSUED. THIS SWELL WILL
REMAIN THE PRIMARY SOUTH SWELL DURING THE REST OF NEXT WEEK AS IT
GRADUALLY FADES BEGINNING ON TUESDAY.
SURF ALONG EAST FACING SHORES WILL REMAIN ROUGH AND CHOPPY THROUGH
THE FORECAST PERIOD AS MODERATE TO LOCALLY STRONG TRADES HOLD. SURF
ALONG NORTH FACING SHORES REMAINS FLAT TO TINY THROUGH MUCH OF
THIS WEEK.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 6 PM HST MONDAY
FOR KAUAI NORTHWEST WATERS-KAUAI WINDWARD WATERS-KAUAI LEEWARD
WATERS-KAUAI CHANNEL-OAHU WINDWARD WATERS-OAHU LEEWARD WATERS-
KAIWI CHANNEL-MAUI COUNTY WINDWARD WATERS-MAUI COUNTY LEEWARD
WATERS-BIG ISLAND WINDWARD WATERS.
SMALL CRAFT ADVISORY UNTIL 6 PM HST MONDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.
DISCUSSION...BOHLIN
AVIATION...EVANS
MARINE...JT
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page