557
FXHW60 PHFO 161954
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
954 AM HST THU APR 16 2026
SYNOPSIS
A LOW PRESSURE SYSTEM LINGERS FAR TO THE NORTH OF HAWAII THIS
MORNING, SUPPORTING CONTINUED LIGHT AND VARIABLE WINDS WITH
CHANCES FOR LIGHT TO MODERATE SHOWERS TODAY. A PASSING HIGH
PRESSURE SYSTEM WILL BRING A BRIEF RETURN TO EASTERLY TRADE WINDS
WITH SUBTLE DRYING TRENDS FROM TONIGHT INTO SATURDAY. A SERIES OF
LOW PRESSURE SYSTEMS PASSING JUST NORTH OF THE STATE WILL PRODUCE
LIGHT TO MODERATE SOUTHEASTERLY WINDS FROM SUNDAY INTO THE MIDDLE
OF NEXT WEEK ALONG WITH ENHANCED SHOWER TRENDS OVER THE WESTERN
ISLANDS ON MONDAY AND TUESDAY.
SHORT TERM UPDATE
ISSUED AT 939 AM HST THU APR 16 2026
NO MAJOR CHANGES TO THE FORECAST THIS MORNING, AS RELATIVELY
BENIGN WEATHER WITH BROKEN TO OVERCAST HIGH CLOUDS (ESPECIALLY
ACROSS THE EASTERN HALF OF THE STATE) CONTINUES. WINDS TODAY ARE
TRANSITIONING BACK TO A MORE EASTERLY TRADE WIND REGIME, BUT WILL
REMAIN LIGHT ENOUGH TO SUPPORT SEA BREEZE DEVELOPMENT IN SHELTERED
AREAS THIS AFTERNOON. KAUAI AND OAHU MAY HAVE SLIGHTLY MORE
SHOWER ACTIVITY VERSUS THE OTHER ISLANDS TODAY DUE TO LESS
OVERCAST CLOUD COVER AND INCREASED DAYTIME HEATING. HOWEVER, NOT
ANTICIPATING MUCH MORE THAN BRIEF SHOWERS STATEWIDE.
PREV DISCUSSION
LOOKING INTO THE WATER VAPOR SATELLITE IMAGERY THIS MORNING WE
CONTINUE TO SEE A DIVERGENT SUB TROPICAL JET STREAM OVER THE
HAWAIIAN ISLANDS PRODUCING EXTENSIVE HIGH LEVEL CIRRUS AND MIDDLE
LEVEL ALTO-CUMULUS CLOUDS. THESE CLOUDY SKIES WILL LINGER INTO
EARLY NEXT WEEK WITH ENOUGH INSTABILITY IN THE ATMOSPHERE TO
SUPPORT BRIEF CHANCES FOR PASSING SHOWERS EACH DAY.
A HIGH PRESSURE SYSTEM WILL PASS BY JUST NORTH OF THE STATE LATER
TONIGHT INTO SATURDAY, BRIEFLY BUILDING IN EASTERLY TRADE WINDS
ACROSS THE REGION. WIND SPEEDS WILL BECOME STRONG ENOUGH TO LIMIT
SEA BREEZES TO TERRAIN SHELTERED LEEWARD WESTERN SLOPES OF EACH
ISLAND. SUBTLE DRYING TRENDS WILL DEVELOP DURING THIS TIME PERIOD
DUE TO A SLIGHT INCREASE IN SUBSIDENCE, DOWNWARD VERTICAL MOTIONS
CREATING WARMING AND DRYING EFFECTS, MAKING THE ATMOSPHERE A BIT
MORE STABLE.
HOWEVER, THE RETURN TO EASTERLY TRADE WINDS WILL BE FLEETING AND
VANISH QUICKLY BY SUNDAY AS A SERIES OF LOW PRESSURE SYSTEMS
DEVELOP AND BREAK DOWN THE RIDGE NORTH OF THE STATE. THESE
PASSING LOWS APPEAR TO TRACK FAR ENOUGH NORTH TO LIMIT ANY HEAVY
RAINFALL OR FLOODING ISSUES FOR THE ISLANDS. A PASSING UPPER LEVEL
TROUGH MAY INCREASE CLOUD AND SHOWER TRENDS OVER THE WESTERN
ISLANDS OF NIIHAU, KAUAI, OAHU AND MOLOKAI FROM MONDAY THROUGH
TUESDAY. A WEAK RIDGE WILL SETTLE IN OVER THE EASTERN ISLANDS
PRODUCING A FAIRLY STABLE SOUTHEASTERLY WIND PATTERN ACROSS THE
REGION. ANY ADDITIONAL ENHANCED SHOWERS IN THIS WIND DRIVEN
PATTERN WILL FAVOR SOUTHEAST SLOPES OF MAUI AND THE BIG ISLAND
WITH MODEST ADDITIONAL RAINFALL AMOUNTS. ELSEWHERE RAINFALL WILL
BE LIMITED AS THE PASSING CLOUD BANDS WILL MOVE MORE PARALLEL TO
ISLAND MOUNTAINS AND THE BIG ISLAND WILL PRODUCE A LEESIDE RAIN
SHADOW ACROSS MUCH OF THE ISLANDS IN MAUI COUNTY.
THE LONG RANGE FORECAST GUIDANCE SHOWS ANOTHER ROUND OF
RETURNING EASTERLY TRADE WINDS FROM NEXT WEEK THURSDAY INTO THE
FOLLOWING WEEKEND. A BUILDING UPPER LEVEL RIDGE WILL KEEP SHOWER
ACTIVITY TO A MINIMUM, WITH BRIEF PASSING SHOWERS FAVORING THE
TYPICAL WINDWARD AND MOUNTAIN AREAS IN THE OVERNIGHT TO EARLY
MORNING HOURS.
AVIATION
ISSUED AT 939 AM HST THU APR 16 2026
A LIGHT BACKGROUND EASTERLY TRADE WIND FLOW SHOULD TAKE PLACE
TODAY. LAND AND SEA BREEZES ARE EXPECTED FOR TERRAIN SHELTERED
AREAS DUE TO THE LIGHT WINDS. IT IS ALSO POSSIBLE FOR AFTERNOON
SHOWERS TO OCCUR OVER ISLAND INTERIORS, PROVIDING ISOLATED MVFR
CONDITIONS FOR THE AFTERNOON HOURS, BEFORE DISSIPATING BY THE
EVENING. WINDWARD AND MOUNTAIN AREAS COULD ALSO SEE BRIEF AND
ISOLATED MVFR CONDITIONS FROM PASSING SHOWERS. VFR WILL PREVAIL
ELSEWHERE.
NO AIRMETS ARE IN EFFECT.
MARINE
ISSUED AT 939 AM HST THU APR 16 2026
TROUGH TO THE NW MAINTAINS GENTLE TO MODERATE EASTERLY TRADES
THROUGH TODAY. THE STRONGEST BREEZES WILL OCCUR THROUGH THE
TYPICAL WINDY CHANNELS SURROUNDING MAUI AND THE BIG ISLAND.
BUILDING HIGH PRESSURE THEN SUPPORTS MODERATE TO LOCALLY FRESH
EASTERLY TRADES ACROSS THE WATERS FRIDAY INTO SATURDAY. WINDS MAY
BRIEFLY REACH THE SMALL CRAFT ADVISORY THRESHOLD ON SATURDAY. LOW
PRESSURE TO OUR NW ON SUNDAY WILL CAUSE TRADES TO WEAKEN SLIGHTLY
AND VEER TO ESE. GENTLE TO MODERATE ESE WINDS ARE EXPECTED SUNDAY
INTO EARLY NEXT WEEK.
A SMALL, SHORT-PERIOD, NNW SWELL FADES THIS AFTERNOON INTO TONIGHT.
SMALL BACKGROUND ENERGY FROM THE W THIS WEEKEND INTO NEXT WEEK
FROM TYPHOON SINLAKU, BUT CONFIDENCE REMAINS LOW. A MUCH LARGER
NW TO WNW SWELL IS POSSIBLE TOWARDS THE END OF NEXT WEEK AS
TYPHOON SINLAKU TRANSITIONS TO EXTRATROPICAL EARLY NEXT WEEK.
A SMALL TO MODERATE, MEDIUM-PERIOD, SSE SWELL BOOSTS SURF ALONG S
SHORES THROUGH FRIDAY THEN LOWERS OVER THE WEEKEND. SURF ALONG E
SHORES REMAINS BELOW THE SEASONAL AVERAGE AS TRADES REMAIN LIGHT.
HOWEVER, INCREASING TRADES BY WEEK'S END SHOULD BRINGS A SLIGHT
BUMP TO SURF. LOW PRESSURE ADVANCING S ALONG THE W COAST OF THE US
NEXT WEEK THEN SENDS A SMALL, MEDIUM PERIOD NE SWELL TOWARD THE
ISLANDS BY MIDWEEK.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM UPDATE...VAUGHAN
DISCUSSION...BOHLIN
AVIATION...DT
MARINE...JVC
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