253
FXHW60 PHFO 290636
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
836 PM HST TUE APR 28 2026
SYNOPSIS
AN UPPER TROUGH WILL SLIDE FROM NORTH OF THE STATE TO THE EAST
THROUGH WEDNESDAY BEFORE SETTLING NORTHEAST OF THE AREA. MODERATE
TO FRESH TRADE WINDS WILL CONTINUE TO FUNNEL IN CLOUDS AND
SHOWERS THAT WILL BE ENHANCED BY THE UPPER TROUGH OVER THE NEXT
SEVERAL DAYS.
SHORT TERM UPDATE
THE BROAD AREA OF HIGH PRESSURE REMAINS NORTH OF THE HAWAIIAN
ISLANDS AND WILL CONTINUE TO SUPPORT MODERATE TRADES THROUGH THE
NEXT SEVERAL DAYS. AN UPPER-LEVEL TROUGH IS STILL DEPICTED TO MOVE
THROUGH THE AREA THROUGH MIDWEEK, SETTLING NORTHEAST OF THE STATE
FOR THE REMAINDER OF THE WEEK BEFORE MEANDERING AWAY BY THE
WEEKEND. THIS WILL BE ADDRESSED IN FURTHER DETAIL WITH THE MORNING
FORECAST PACKAGE. OTHERWISE, NO AMENDMENTS WERE NEEDED TO THE
LATEST FORECAST AS IT CONTINUES TO REMAIN ON TRACK.
PREV DISCUSSION
ISSUED AT 355 PM HST TUE APR 28 2026
AN UPPER TROUGH NORTH OF HAWAII WILL DIVE SOUTHEASTWARD THROUGH
WEDNESDAY. THE TROUGH WILL FORM A CUTOFF LOW AND BECOME
STATIONARY AROUND 600 MILES NORTHEAST OF HAWAII THROUGH FRIDAY
NIGHT BEFORE SHIFTING AWAY THIS WEEKEND. MEANWHILE, MODERATE TO
FRESH TRADE WINDS CONTINUE AT THE SURFACE. CURRENT VISIBLE
SATELLITE SHOWS CLOUD BUILD UPS ACROSS EAST MAUI AND BIG ISLAND
AND PARTLY CLOUDS ELSEWHERE WHERE TRADES ARE BLOWING THIS
AFTERNOON. RADAR SHOWS HEAVY SHOWERS POPPING UP ACROSS THE BIG
ISLAND DUE TO SEA BREEZE CONVERGENCE AND INSTABILITY FROM THE
UPPER TROUGH. EXPECT THESE SHOWERS TO WANE AROUND SUNSET. 00Z
SOUNDINGS SHOW NO INVERSION PRESENT WITH WITH A NARROW BAND OF
CAPE TO THE EQUILIBRIUM LEVEL AT BOTH HILO AND LIHUE. PRECIPITABLE
WATER VALUES ARE AVERAGE 1.2 TO 1.3 INCHES.
INSTABILITY GENERATED BY THE COLD POOL ALOFT WILL ENHANCE SHOWERS
AND BRING A SLIGHT CHANCE OF THUNDERSTORMS ON THE BIG ISLAND
AGAIN WEDNESDAY AFTERNOON. WINDWARD SHOWERS WILL SEE THE HIGHEST
ACTIVITY DURING THE OVERNIGHT TO EARLY MORNING HOURS.
THE UPPER LOW NORTHEAST OF THE ISLANDS WILL KEEP INVERSION AND
CLOUD HEIGHTS ELEVATED, ALLOWING PERIODS OF SHOWERS TO CONTINUE
THROUGH THE SECOND HALF OF 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.
AVIATION
ISSUED AT 355 PM HST TUE APR 28 2026
WHILST UNDERGOING MODEST STRENGTHENING INTO TOMORROW, LOCALLY
BREEZY TRADES CONTINUE TO DELIVER SHOWERS WINDWARD AND MAUKA.
ISOLATED MVFR POSSIBLE WITHIN HEAVIER SHOWERS, BUT VFR PREVAILS,
EXCEPT PERHAPS WINDWARD BIG ISLAND WHERE OBSERVATIONAL TRENDS AND
THE LATEST GUIDANCE SUGGEST A GREATER COVERAGE OF SHOWERS AND MVFR
POTENTIAL TONIGHT.
AIRMET SIERRA MAY BE NEEDED FOR WINDWARD BIG ISLAND TONIGHT.
AIRMET TANGO FOR LEE TURB MAY BE NEEDED AS EARLY AS WEDNESDAY
AFTERNOON AS TRADES STRENGTHEN.
NO AIRMETS IN EFFECT.
MARINE
ISSUED AT 355 PM HST TUE APR 28 2026
MODERATE TO FRESH EAST-NORTHEAST TRADES WILL CONTINUE TONIGHT
BEFORE STRENGTHENING ON WEDNESDAY AS A WEAK TROUGH SHIFTS TO THE
WEST AND A RIDGE BUILDS NORTH OF THE STATE. A SMALL CRAFT
ADVISORY (SCA) HAS BEEN ISSUED FOR THE TYPICALLY WINDIER WATERS
SURROUNDING MAUI COUNTY AND THE BIG ISLAND BEGINNING WEDNESDAY
MORNING. THE SCA IS LIKELY TO BE EXTENDED THROUGH AT LEAST FRIDAY
BEFORE A TROUGH APPROACHES FROM THE NORTHWEST THIS WEEKEND, WHICH
WILL LEAD TO A PERIOD OF MORE RELAXED TRADE WINDS.
OFFSHORE BUOYS CONTINUE TO SHOW THE NEW NORTHWEST SWELL AROUND OR
BELOW 1 FT. AS A RESULT, SURF ALONG NORTH AND WEST FACING SHORES
WILL REMAIN SMALL TONIGHT BEFORE A SMALL BUMP IS POSSIBLE ON
WEDNESDAY. AN UPWARD TREND IS THEN EXPECTED DURING THE SECOND HALF
OF THE WEEK AS ANOTHER NORTHWEST SWELL ARRIVES AS EARLY AS
WEDNESDAY NIGHT. THIS SWELL ORIGINATES FROM A STORM-FORCE LOW THAT
TRACKED INTO THE BERING SEA THIS PAST WEEKEND, AS CONFIRMED BY
SCATTEROMETRY. THEREFORE, THIS SWELL APPEARS MORE LIKELY TO
MATERIALIZE. 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 THURSDAY AND
FRIDAY AS TRADES STRENGTHEN.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY FROM 6 AM WEDNESDAY TO 6 AM HST THURSDAY
FOR KAHOOLAWE.
SMALL CRAFT ADVISORY FROM 6 AM WEDNESDAY TO 6 AM HST THURSDAY
FOR ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG ISLAND
SOUTHEAST WATERS-MAALAEA BAY-PAILOLO CHANNEL.
SHORT TERM UPDATE...PIERCE
DISCUSSION...FOSTER
AVIATION...JVC
MARINE...QUESADA
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