031
FXHW60 PHFO 281314
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
314 AM HST TUE APR 28 2026
SYNOPSIS
MODERATE EASTERLY TRADE WINDS WILL CONTINUE INTO EARLY NEXT WEEK.
AN UPPER LEVEL TROUGH APPROACHING THE ISLANDS AND WILL DEEPEN
INTO AN UPPER LOW JUST NORTH OF KAUAI TODAY. THIS UPPER DISTURBANCE
WILL PASS SLOWLY THROUGH THE REGION AND THEN LINGER NORTHEAST OF
THE STATE INTO THE WEEKEND. EXPECT PERIODS OF ENHANCED CLOUDS AND
SHOWERS ACROSS THE REGION THROUGH THE WEEK. SHOWER ACTIVITY WILL
FAVOR WINDWARD MOUNTAIN AREAS IN THE OVERNIGHT TO EARLY MORNING
HOURS, WITH BRIEF PERIODS OF SHOWERS DRIFTING INTO LEEWARD AREAS.
LOCATIONS SHELTERED FROM THE MODERATE EASTERLY TRADE WINDS COULD
ALSO SEE INCREASED CLOUDS AND A FEW SHOWERS DURING THE AFTERNOONS.
DISCUSSION
THE WATER VAPOR SATELLITE IMAGERY CHANNEL SHOWS THE UPPER LEVEL
TROUGH MOVING INTO THE WESTERN ISLANDS THIS MORNING CONTINUES TO
DEEPEN INTO AN UPPER LEVEL LOW FORECAST TO TRACK SLOWLY EASTWARD
THROUGH THE ISLAND CHAIN. THIS UPPER LOW WILL LIFT SUBSIDENCE
TEMPERATURE INVERSION HEIGHTS AND ENHANCE CLOUDS AND SHOWERS
ACROSS THE STATE. WINDWARD MOUNTAINS WILL SEE THE HIGHEST SHOWER
ACTIVITY DURING THE OVERNIGHT TO EARLY MORNING HOURS, WHILE
TERRAIN SHELTERED LEEWARD WESTERN MOUNTAINS WILL SEE SEA BREEZE
TRADE WIND CONVERGENCE ZONES TRIGGERING ENHANCED SHOWERS DURING
THE AFTERNOON HOURS EACH DAY.
THE UPPER LOW AND TRAILING UPPER TROUGH WILL SLOW DOWN AND REMAIN
JUST NORTHEAST OF THE HAWAIIAN ISLANDS INTO THE WEEKEND. THE UPPER
LEVEL LIFT JUST UPSTREAM OF THE ISLANDS WILL KEEP INVERSION
AND CLOUD HEIGHTS ELEVATED, ALLOWING PERIODS OF SHOWERS TO
CONTINUE THROUGH THE WEEK. ONLY SUBTLE DAY TO DAY CHANGES IN
ISLAND WEATHER PATTERNS ARE EXPECTED. THIS WET TRADE WIND PATTERN
MAY LINGER INTO THE FIRST HALF OF NEXT WEEK AS A SHALLOW COLD
FRONT AND UPPER LEVEL TROUGH APPROACH THE ISLANDS FROM THE
NORTHWEST. THE WET SEASON CONTINUES INTO THE FIRST WEEK OF MAY.
AVIATION
MODERATE TO LOCALLY BREEZY TRADE WINDS WILL CONTINUE DURING THE
NEXT COUPLE OF DAYS. SCATTERED TO NUMEROUS SHOWER ACTIVITY CAN BE
EXPECTED OVER THE NEXT 24 HOURS OR SO ACROSS WINDWARD AND
MOUNTAIN AREAS AS AN UPPER LEVEL TROUGH MOVES ACROSS THE REGION.
AIRMET SIERRA IS CURRENTLY IN EFFECT FOR WINDWARD AREAS ACROSS THE
STATE DUE TO DEGRADED CIGS UNDER SHOWERS, HOWEVER THIS IS
EXPECTED TO IMPROVE DURING THE DAY TODAY.
MARINE
MODERATE TO FRESH EAST-NORTHEAST TRADES WILL CONTINUE TODAY
BEFORE STRENGTHENING LATE TONIGHT INTO TOMORROW AS A WEAK TROUGH
SHIFTS TO THE WEST AND A RIDGE BUILDS NORTH OF THE STATE. THIS
WILL LIKELY CORRESPOND TO SMALL CRAFT ADVISORY WINDS ACROSS THE
TYPICALLY WINDIER WATERS SURROUNDING MAUI COUNTY AND THE BIG
ISLAND BEGINNING WEDNESDAY.
A SMALL BUMP IN SURF IS EXPECTED TODAY WITH THE ARRIVAL OF A
SMALL NORTHWEST SWELL. AN UPWARD TREND IS EXPECTED DURING THE
SECOND HALF OF THE WEEK AS ANOTHER NORTHWEST SWELL ARRIVES.
LOOKING FURTHER AHEAD, A STORM- FORCE LOW EAST OF JAPAN WILL SEND
A MODERATE, LONGER-PERIOD NORTHWEST SWELL TOWARD THE ISLANDS FOR
FRIDAY AND SATURDAY, WITH SURF HEIGHTS POTENTIALLY APPROACHING
ADVISORY LEVELS ALONG EXPOSED NORTH AND WEST FACING SHORES.
SURF ALONG SOUTH-FACING SHORES WILL REMAIN SMALL THROUGH MUCH OF THE
WEEK, WITH MAINLY BACKGROUND SOUTH TO SOUTHWEST SWELL EXPECTED.
ANOTHER SOUTH-SOUTHWEST PULSE MAY ARRIVE BY THIS WEEKEND FROM RECENT
ACTIVITY WITHIN OUR SWELL WINDOW EAST OF NEW ZEALAND, PROVIDING A
SMALL INCREASE IN SURF.
SURF ALONG EAST-FACING SHORES WILL REMAIN RELATIVELY SMALL AND
CHOPPY THROUGH MIDWEEK, WITH A SLIGHT RISE POSSIBLE LATER IN THE
WEEK AS TRADES STRENGTHEN.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...BOHLIN
AVIATION...EVANS
MARINE...WALSH
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