409
FXHW60 PHFO 150119
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
319 PM HST MON JUL 14 2025
SYNOPSIS
HIGH PRESSURE WILL REMAIN FAR NORTH NORTHEAST OF THE AREA THIS
WEEK. A WEAK SURFACE TROUGH WILL MOVE THROUGH THE ISLANDS AND
BRING AN INCREASE IN SHOWERS THROUGH TUESDAY MORNING. DRY, STABLE
WEATHER IS EXPECTED TUESDAY THROUGH FRIDAY. A BROAD, WEAK UPPER
LOW WILL SET UP OVER AND NORTH OF THE ISLANDS BY LATE FRIDAY
BRINGING INCREASING TRADE WIND SHOWERS.
DISCUSSION
A PERSISTENT 1038 MB SURFACE HIGH IS CENTERED FAR NORTH NORTHEAST
OF HAWAII THIS AFTERNOON DRIVING MODERATE TO FRESH TRADE WINDS. A
WEAK SURFACE TROUGH MOVING ONTO THE ISLAND CHAIN FROM THE EAST IS
CAUSING A BRIEF WEAKNESS IN THE WIND FLOW AND IS EXPECTED TO BRING
A ROUND OF SHOWERS MAINLY TO WINDWARD AREAS OVERNIGHT. THE TROUGH
EXTENDS PAST 700 MB (10,000 FEET) WHICH COULD RESULT IN SOME
MODERATE INTENSITY TRADE WIND SHOWERS, AND POSSIBLY BRING A FEW TO
LEEWARD SIDES OF THE SMALLER ISLANDS. SHOWERS MAY LINGER AROUND
KAUAI TUESDAY MORNING AS THE TROUGH WEAKENS, BUT OVERALL EXPECT A
DRIER AND MORE STABLE ENVIRONMENT AND STRENGTHENING WIND SPEEDS
TUESDAY. LITTLE CHANGE IS EXPECTED TO FORECAST TUESDAY THROUGH
FRIDAY WITH ANY INCOMING CLOUDS AND SHOWERS IMPACTING WINDWARD
SLOPES OCCURRING MAINLY AT NIGHT.
A BROAD, WEAK UPPER LOW WILL SET UP OVER AND NORTH OF THE ISLANDS
BY LATE FRIDAY. A SLIGHT INCREASE IN SHOWER TRENDS ARE
ANTICIPATED MAINLY DURING THE OVERNIGHT TO EARLY MORNING HOURS
FAVORING THE WINDWARD AND MOUNTAIN AREAS THROUGH THE WEEKEND.
AVIATION
HIGH PRESSURE NORTH OF THE STATE WILL MAINTAIN MODERATE TO
LOCALLY BREEZY TRADES. SHOWER TRENDS WILL START TO INCREASE
LATER THIS EVENING AND INTO TONIGHT AS AN AREA OF MOISTURE
MOVES INTO THE REGION. CLOUDS AND SHOWERS WILL FAVOR MAINLY
WINDWARD AND MAUKA AREAS, WITH PERIODS OF MVFR POSSIBLE LATE
TONIGHT INTO TUESDAY MORNING.
NO AIRMETS ARE IN EFFECT, BUT AIRMET SIERRA FOR MOUNTAIN
OBSCURATION IS POSSIBLE ACROSS WINDWARD SLOPES TONIGHT AS
CLOUDS AND SHOWERS INCREASE ACROSS THE ISLANDS.
MARINE
A RIDGE OF HIGH PRESSURE WILL REMAIN FAR NORTH OF THE STATE
THROUGHOUT THE WEEK. MODERATE TO FRESH TRADES THIS AFTERNOON WILL
GRADUALLY STRENGTHEN ON TUESDAY AS THE RIDGE OF HIGH PRESSURE
STRENGTHENS. SMALL CRAFT ADVISORY (SCA) HAS BEEN POSTED FOR THE
TYPICAL WINDY AREAS AROUND MAUI COUNTY AND THE BIG ISLAND STARTING
TUESDAY MORNING. FRESH TO LOCALLY STRONG TRADE WINDS WILL LIKELY
PERSIST THROUGH MOST OF THE WEEK, ALTHOUGH WE COULD SEE WINDS DROP
BELOW SCA THRESHOLDS AS A WEAK TROUGH DEVELOPS OVER THE WESTERN
END OF THE STATE FRIDAY INTO THE WEEKEND.
SURF ALONG SOUTH FACING SHORES SHOULD SEE A MODEST INCREASE OVER
THE NEXT FEW DAYS DUE TO A PAIR OF SOUTH AND SOUTH-SOUTHEAST
SWELLS. A LONG-PERIOD SOUTH SWELL CONTINUES TO SLOWLY FILL IN
TODAY AND THIS SWELL SHOULD PEAK ON TUESDAY NEAR SUMMER AVERAGES.
AS THIS SWELL DECLINES A REINFORCING SWELL FROM THE SOUTH-
SOUTHEAST SHOULD FILL IN TUESDAY OR WEDNESDAY. THIS SHOULD
MAINTAIN SURF HEIGHTS THROUGH THE MIDDLE OF THE WEEK. SURF SHOULD
GRADUALLY DECLINE THURSDAY INTO FRIDAY, BUT ANOTHER SMALL INCREASE
IS EXPECTED INTO THE WEEKEND AS A NEW LONG-PERIOD SOUTHWEST SWELL
ARRIVES FROM THE TASMAN SEA.
SURF ALONG EAST FACING SHORES WILL CONTINUE TO REMAIN CHOPPY WITH
SURF HEIGHTS BELOW AVERAGE DUE TO THE LACK OF STRONG TRADES
LOCALLY AND UPSTREAM OF THE STATE. A SIGHT INCREASE IS EXPECTED
TOWARDS THE MIDDLE OF THE WEEK AS THE TRADES STRENGTHEN. A TINY
NORTHWEST SWELL CONTINUES TO FILL IN THIS AFTERNOON AND WILL
LIKELY PEAK TONIGHT AND FADE OUT BY WEDNESDAY.
FIRE WEATHER
TRADE WINDS WILL REMAIN IN THE MODERATE TO LOCALLY BREEZY RANGE
INTO THE UPCOMING WEEKEND. ASIDE FROM A PERIOD OF HIGHER HUMIDITY
AND AN INCREASE IN SHOWER ACTIVITY THROUGH TUESDAY, THEN THE
ATMOSPHERE WILL REMAIN RATHER DRY THROUGH FRIDAY.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION/FIRE WEATHER...FOSTER
AVIATION...AHUE
MARINE...KINO
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