970
FXHW60 PHFO 060118
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
318 PM HST WED AUG 5 2026
SYNOPSIS
LIGHT TO MODERATE TRADE WINDS WILL PREVAIL FOR THE NEXT FEW DAYS,
FOLLOWED BY INCREASING TRADE WIND SPEEDS THIS WEEKEND. MEANWHILE,
AN UPPER DISTURBANCE JUST TO THE NORTHWEST WILL ENHANCE SHOWERS
OVER THE WESTERN END OF THE STATE THROUGH THURSDAY. THE FOCUS FOR
INCREASED SHOWERS WILL SHIFT TO THE EASTERN END OF THE STATE THIS
WEEKEND AS AN AREA OF TROPICAL MOISTURE PASSES BY.
DISCUSSION
WATER VAPOR IMAGERY SHOWS AN UPPER LOW WEST OF THE MAIN HAWAIIAN
ISLANDS THIS AFTERNOON. THIS FEATURE IS GENERATING INSTABILITY
AND WIND SHEAR ACROSS THE WESTERN END OF THE STATE THAT WILL LAST
UNTIL THURSDAY. THE UPPER LOW IS FORECAST TO LIFT AWAY TO THE
NORTH ON FRIDAY, RETURNING MORE STABLE CONDITIONS TO THE AREA.
MEANWHILE, TRADE WINDS WILL REMAIN AT ONLY LIGHT TO MODERATE
SPEEDS FOR THE NEXT COUPLE OF DAYS AS THE REMNANTS OF FORMER
TROPICAL CYCLONE GENEVIEVE HAVE CUT OFF THE HIGH PRESSURE TO OUR
NORTH, INTERRUPTING THE TRADE WIND FLOW. THE WEAKER TRADES WILL
LIKELY RESULT IN LOCALIZED SEA BREEZES EACH AFTERNOON, BRINGING
INCREASED CLOUD BUILDUPS AND A FEW SHOWERS EACH AFTERNOON. SHOWERS
WILL BE MORE PROMINENT ACROSS KAUAI AND OAHU DUE TO MORE
AVAILABLE MOISTURE AND INSTABILITY. BY THE WEEKEND, TRADE WINDS
WILL INCREASE BACK TO LOCALLY BREEZY LEVELS.
THE FORECAST BECOMES MORE INTERESTING AGAIN THIS WEEKEND AS MODEL
GUIDANCE CONTINUES TO SUGGEST THAT A PLUME OF MOISTURE WILL EITHER
MOVE OVER OR VERY NEAR THE EASTERN END OF THE STATE LATE SATURDAY
INTO SUNDAY. DESPITE MOST GUIDANCE KEEPING THE BULK OF THE
MOISTURE JUST SOUTH OF THE STATE, IT IS LIKELY THAT AT LEAST SOME
OF THE ENHANCED TROPICAL MOISTURE WILL BECOME EMBEDDED WITHIN THE
TRADE WIND FLOW, INCREASING SHOWERS FOR MAUI AND THE BIG ISLAND.
AVIATION
A WEAK HIGH PRESSURE RIDGE FAR NORTH OF THE STATE WILL MAINTAIN
GENTLE TO MODERATE TRADE WINDS THROUGH THURSDAY. OVERALL, A
FAIRLY DRY AFTERNOON AND EVENING IS EXPECTED, BUT A SLIGHT
INCREASE OF SHOWERS IS EXPECTED LATE TONIGHT INTO THURSDAY
MORNING, MAINLY OVER WINDWARD AREAS. SOME OF THESE SHOWERS COULD
PRODUCE BRIEF MVFR CEILINGS OVER SELECT AREAS.
NO AIRMETS ARE IN EFFECT. AIRMET SIERRA MAY BE NEEDED ACROSS
SELECT WINDWARD AREAS LATE TONIGHT INTO THURSDAY MORNING DEPENDING
ON SHOWER COVERAGE.
MARINE
MODERATE TRADES PERSIST AS SURFACE TROUGHING TO THE NE MAINTAINS A
RATHER WEAK PRESSURE GRADIENT OVER THE STATE. DISSIPATION OF THE
TROUGH TO THE NE COMBINED WITH RENEWED TROUGH DEVELOPMENT S OF THE
ISLANDS WILL FAVOR BREEZY TRADES BY WEEK'S END.
EXISTING SMALL S SWELL WILL FADE TONIGHT AND WILL BE
QUICKLY REPLACED BY A SIMILARLY SIZED MEDIUM PERIOD S SWELL DURING
THURSDAY. SMALL, MEDIUM PERIOD ENERGY REMAINS PREVALENT HEADING INTO
THE WEEKEND. A LARGER, MEDIUM TO LONG PERIOD S SWELL ARRIVES EARLY
NEXT WEEK AND LIKELY PEAKS SHY OF THE HIGH SURF ADVISORY THRESHOLD BY
THE MIDDLE OF NEXT WEEK. LONG PERIOD FORERUNNERS ARE EXPECTED TO
ARRIVE AS EARLY AS FRIDAY EVENING OR FRIDAY NIGHT.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...FOSTER
AVIATION...KINO
MARINE...JVC
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