090
FXHW60 PHFO 310132
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
332 PM HST FRI MAY 30 2025
SYNOPSIS
STABLE, BREEZY TRADES CONTINUE THROUGH THE NEXT SEVEN DAYS,
BRIEFLY INTERRUPTED BY DIMINISHING AND VEERING OF WINDS TO SE
EARLY NEXT WEEK. ENHANCED SHOWER ACTIVITY POSSIBLE IN THE VICNIITY
OF KAUAI ON SUNDAY AND MONDAY.
DISCUSSION
THE ISLANDS RESIDE BENEATH THE INFLECTION POINT BETWEEN LOW
AMPLITUDE SHORTWAVE RIDGING TO THE EAST AND A 588DM 500MB CLOSED LOW
POSITIONED TO THE WEST NEAR 175W. THE WEAK SUBTROPICAL JET SOUTH OF
THE LATTER FEATURE IS STEERING POCKETS OF HIGH CLOUDS ACROSS AREA
SKIES AND WILL CONTINUE TO DO SO FOR THE NEXT FEW DAYS. TYPICAL HIGH
STABILITY TRADE WIND SOUNDINGS ARE OBSERVED AT LIHUE AND HILO THIS
AFTERNOON AS A BATCH OF MOISTURE EMBEDDED WITHIN PREVAILING BREEZY
TRADES WORKS WESTWARD ACROSS THE ISLAND CHAIN. SLIGHT ENHANCEMENT OF
SHOWERS WINDWARD AND MAUKA THIS AFTERNOON INTO TONIGHT ACROSS THE
WESTERN END OF THE STATE AS THIS FEATURE TREKS WEST.
THE WEEKEND WILL BE CHARACTERIZED BY THE EVOLUTION OF THE UPPER
TROUGH WEST OF KAUAI AS IT SHARPENS AND IS USHERED EAST BY UPSTREAM
MID-LATITUDE ENERGY. ATTENDANT SURFACE PRESSURE FALLS WILL WEAKEN
THE GRADIENT LOCALLY WHILE LOW-LEVEL FLOW VEERS TO A MORE ESE
DIRECTION. FROM A SENSIBLE WEATHER STANDPOINT, THIS MAY FAVOR A
COUPLE DAYS OF A SEA BREEZE PATTERN WITH INTERIOR CLOUDS AND
SHOWERS, PARTICULARLY OVER KAUAI, EARLY NEXT WEEK. OTHERWISE,
GENERALLY ANTICIPATE AN INCREASE IN HUMIDITY STATEWIDE AS AMBIENT
SEA LEVEL DEWPOINTS REACH OR ECLIPSE 70F WHILE SHOWER COVERAGE
DIMINISHES (PARTICULARLY LEEWARD) IN RESPONSE TO 850MB STEERING FLOW
ORIENTING INCREASINGLY PARALLEL TO THE ISLANDS.
MEDIUM TO LONG RANGE GUIDANCE MAINTAINS STRONG CONSENSUS THAT
RENEWED UPPER LOW DEVELOPMENT WEST OF KAUAI WILL CONTRIBUTE TO
DIMINISHED STABILITY OVER THE WESTERN END OF THE STATE INTO MID-WEEK
AS BREEZY TRADES RETURN.
AVIATION
AIRMET TANGO HAS BEEN ISSUED FOR ALL LEEWARD LOCATIONS ALONG THE
ISLAND CHAIN AS TRADEWINDS HAVE STRENGTHENED TODAY UNDER A STABLE
ATMOSPHERE GENERATING MODERATE TURBULENCE. THE AIRMET WILL LIKELY
CONTINUE THROUGH SATURDAY AS MODERATE TO STRONG TRADES HOLD
BEFORE VEERING EAST SOUTHEASTERLY LATE SATURDAY INTO SUNDAY.
ISOLATED TO SCATTERED CLOUDS AND EMBEDDED SHOWERS WITHIN THE
TRADEWIND FLOW WILL MAINTAIN VFR CONDITIONS THROUGH THE REST OF
THE DAY. MVFR CONDITIONS MAY DEVELOP ALONG WINDWARD
LOCATIONS OVERNIGHT AND INTO THE EARLY MORNING HOURS SATURDAY AS
SHOWERS INCREASE WITH THE DIURNAL PATTERN.
MARINE
FRESH TO STRONG TRADES WILL CONTINUE TO FILL IN THIS AFTERNOON AS
THE SURFACE RIDGE BUILDS NORTH OF THE ISLANDS. EXPECT THE
STRONGEST WINDS OVER THE TYPICALLY WINDIER CHANNELS AND WATERS
AROUND MAUI COUNTY AND THE BIG ISLAND TO PERSIST THROUGH SATURDAY.
FORECAST GUIDANCE SUGGESTS THE RIDGE WILL BRIEFLY WEAKEN THROUGH
THE LATTER HALF OF THE WEEKEND AND AS A BROAD SURFACE TROUGH
DEVELOPS FAR NORTHWEST OF THE AREA. THIS WILL LEAD TO THE TRADES
VEERING OUT OF THE EAST-SOUTHEAST TO SOUTHEAST BY SUNDAY, WITH
LIGHTER WINDS OVER THE WESTERN END OF THE STATE AND FRESH TRADES
CONTINUING OVER THE EASTERN END. TRADES WILL SHIFT BACK OUT OF THE
EAST AND STRENGTHEN EARLY NEXT WEEK AS THE TROUGH WEAKENS AND
TRACKS AWAY FROM THE AREA.
SURF ALONG EXPOSED NORTH AND WEST-FACING SHORES WILL CLIMB WELL
ABOVE AVERAGE FOR THIS TIME OF YEAR ON SATURDAY AS A FRESH,
MEDIUM-PERIOD NORTH-NORTHWEST (330-340 DEGREES) SWELL ARRIVES.
LATEST BUOY REPORTS ARE SHOWING THE SWELL ARRIVING AT BUOY 51101
THIS AFTERNOON, WHICH IS SLIGHTLY EARLIER THAN GUIDANCE. THIS
NORTH- NORTHWEST SOURCE SHOULD PEAK ON SATURDAY THEN STEADILY
DECLINE SATURDAY NIGHT THROUGH EARLY NEXT WEEK.
SURF ALONG EXPOSED SOUTH-FACING SHORES WILL CONTINUE TO SEE A MIX
OF LONG-PERIOD BACKGROUND SOUTH-SOUTHWEST AND SHORTER- PERIOD
SOUTHEAST SWELL THROUGH THE MIDDLE OF NEXT WEEK. ANOTHER LONG-
PERIOD SOUTH- SOUTHWEST SWELL IS POSSIBLE LATE NEXT WEEK DUE TO A
SYSTEM PASSING THROUGH OUR SWELL WINDOW NEAR NEW ZEALAND. IF THIS
MATERIALIZES, SURF COULD CLIMB TO ABOVE AVERAGE LEVELS BY NEXT
WEEKEND.
SURF ALONG EAST-FACING SHORES WILL GRADUALLY BUILD OVER THE
WEEKEND AND INTO EARLY NEXT WEEK AS BREEZY TO STRONG TRADE WINDS
RETURN UPSTREAM OF THE STATE.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 PM HST SATURDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.
DISCUSSION...JVC
AVIATION...ALMANZA/FOSTER
MARINE...FARRIS/KINO
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