231
FXHW60 PHFO 131922
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
922 AM HST MON JUL 13 2026
SYNOPSIS
LOCALLY BREEZY TRADE WINDS WILL EASE TO MODERATE LEVELS TUESDAY
AND WEDNESDAY, THEN STRENGTHEN THURSDAY INTO THE WEEKEND. SHOWERS
WILL CONTINUE TO FAVOR WINDWARD AND MAUKA AREAS, WITH A SLIGHT
UPTICK IN MOISTURE EXPECTED TUESDAY AND WEDNESDAY.
DISCUSSION
TRADE WINDS HAVE EASED SLIGHTLY COMPARED TO THE PAST SEVERAL DAYS
BUT WILL REMAIN LOCALLY BREEZY TODAY. THE SURFACE HIGH DRIVING THE
TRADES REMAINS QUITE STRONG AT 1034 MB FAR NORTH OF HAWAII, BUT A
WEAK MID-LEVEL TROUGH JUST NORTHEAST OF THE ISLANDS IS BEGINNING
TO ERODE THE LOCAL PRESSURE GRADIENT. AS THE TROUGH DRIFTS
WESTWARD THROUGH TONIGHT, TRADES WILL CONTINUE A GRADUAL DECLINE.
EVEN WITH THE MID-LEVEL TROUGH NEARBY, STABLE CONDITIONS WILL
PERSIST, KEEPING SHOWERS FOCUSED ACROSS TYPICAL WINDWARD AND MAUKA
AREAS. THE GREATEST AMOUNT OF RAINFALL TODAY WILL BE ON WINDWARD
BIG ISLAND, WHERE A NARROW LINE OF MOISTURE IS PRODUCING ENHANCED
SHOWERS.
A NOTICEABLE DECREASE IN TRADE WINDS WILL OCCUR TUESDAY AND
WEDNESDAY. THE POSITIONS OF THE SURFACE HIGH WILL CHANGE LITTLE,
BUT THE MID-LEVEL TROUGH WILL DRIFT WESTWARD OVER THE ISLANDS,
LEADING TO A WEAKENING OF THE LOCAL PRESSURE GRADIENT AND
RESULTING TRADES. GUIDANCE SUGGESTS THAT SHALLOW MOISTURE RIDING
ALONG THE MODERATE TRADE WIND FLOW WILL KEEP WINDWARD SHOWER
ACTIVITY SOMEWHAT ENHANCED. IF TRADES WEAKEN ENOUGH, LOCALIZED SEA
BREEZES COULD PRODUCE CLOUDS AND A FEW SHOWERS ACROSS LEEWARD
TERRAIN EACH AFTERNOON.
TRADE WINDS SHOULD REBUILD THURSDAY AND FRIDAY AS THE MID-LEVEL
TROUGH MOVES AWAY. ANOTHER FACTOR IN THE THE RESTRENGTHENING
TRADE WINDS COULD BE DEVELOPMENT OF A TROPICAL CYCLONE FAR SOUTH
OF HAWAII. AT THIS TIME, IT DOES NOT APPEAR THAT ANY OF THIS
TROPICAL ACTIVITY WOULD DIRECTLY IMPACT THE ISLANDS.
AVIATION
BREEZY TRADE WINDS WILL GRADUALLY EASY THROUGH TUESDAY, CARRYING
INTERMITTENT SHOWERS INTO WINDWARD AREAS OF THE ISLANDS THROUGH
THE FORECAST PERIOD, MOST ACTIVE IN THE OVERNIGHT AND EARLY
MORNING HOURS. MVFR CONDITIONS ARE POSSIBLE UNDER SHOWERS, THOUGH
VFR IS GENERALLY EXPECTED TO PREVAIL. TRADE WINDS ARE EXPECTED TO
GRADUALLY WEAKEN OVER THE NEXT FEW DAYS.
AIRMET TANGO REMAINS IN EFFECT FOR LOW-LEVEL TURBULENCE OVER
AND DOWNWIND OF TERRAIN, AND IS EXPECTED TO CONTINUE FOR THE NEXT
DAY OR SO AS WE REMAIN UNDER A BREEZY TRADE WIND PATTERN.
MARINE
TRADE WINDS WILL GRADUALLY EASE THROUGH TUESDAY AS THE HIGH
PRESSURE NORTH OF THE ISLANDS LIFTS NORTHEAST AND WEAKENS. A SMALL
CRAFT ADVISORY (SCA) IS NOW IN EFFECT FOR MOST WATERS THROUGH
THIS EVENING AND WILL GET TRIMMED THROUGH TONIGHT TO MAINLY THE
WINDIER WATERS AND CHANNELS AROUND MAUI COUNTY AND THE BIG ISLAND.
THE SCA WILL LIKELY NOT BE NEEDED FOR ANY WATERS TUESDAY AS WINDS
SHOULD HAVE DECREASED TO BELOW CRITERIA. THESE LIGHTER TRADES
SHOULD CONTINUE THROUGH WEDNESDAY NIGHT, THEN MAY INCREASE A BIT
THURSDAY AND FRIDAY AS HIGH PRESSURE NORTHEAST OF THE ISLANDS
DROPS A BIT FURTHER SOUTH AND TIGHTENS UP THE LOCAL PRESSURE
GRADIENT.
THE CURRENT SMALL, LONG-PERIOD SOUTHWEST SWELL WILL PEAK TODAY,
THEN GRADUALLY DECLINE THROUGH THE MIDDLE OF THE WEEK. A SERIES OF
OVERLAPPING SMALL SOUTH AND SOUTHWEST SWELLS WILL THEN GIVE A
SMALL BOOST TO THE SURF ALONG SOUTH FACING SHORES THURSDAY THROUGH
NEXT WEEKEND, WITH PERHAPS A MORE SIZABLE SOUTH SWELL MOVING IN
EARLY NEXT WEEK.
SURF ALONG EAST-FACING SHORES WILL STEADILY DECLINE THROUGH THE
MIDDLE OF THE WEEK. SURF WILL THEN HOLD STEADY AT SLIGHTLY BELOW
NORMAL LEVELS ALONG EAST FACING SHORES LATE IN THE WEEK THROUGH
THE WEEKEND.
A SERIES OF SMALL, LONG TO MEDIUM PERIOD WEST TO WEST-NORTHWEST
SWELLS GENERATED BY FORMER SUPER TYPHOON BAVI WILL BE POSSIBLE
THROUGHOUT THE WEEK. OTHERWISE, NO SIGNIFICANT NORTH OR NORTHWEST
SWELLS ARE EXPECTED, SO SURF ALONG NORTH-FACING SHORES IS EXPECTED
TO REMAIN FLAT TO TINY.
PEAK MONTHLY HIGH TIDES COMBINED WITH WATER LEVELS THAT ARE
RUNNING SLIGHTLY HIGHER THAN PREDICTED WILL LEAD TO MINOR FLOODING
ALONG THE SHORELINE AND IN LOW-LYING COASTAL AREAS. COASTAL
FLOODING IS POSSIBLE AROUND THE DAILY PEAK TIDE, WHICH WILL BE
DURING THE AFTERNOON HOURS. A COASTAL FLOOD STATEMENT REMAINS IN
EFFECT THROUGH TUESDAY AFTERNOON.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 AM HST TUESDAY FOR KAUAI NORTHWEST
WATERS-KAUAI LEEWARD WATERS-MAALAEA BAY-PAILOLO CHANNEL-
ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG ISLAND
SOUTHEAST WATERS.
SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR KAIWI
CHANNEL-MAUI COUNTY WINDWARD WATERS-MAUI COUNTY LEEWARD WATERS.
DISCUSSION...WROE
AVIATION...TS
MARINE...SHIGESATO
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