135
FXHW60 PHFO 071407
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
407 AM HST THU MAY 7 2026
SYNOPSIS
TRADE WINDS WILL RETURN THE NEXT COUPLE OF DAYS UNDER TYPICALLY
PARTLY CLOUDY CONDITIONS. PRECIPITATION WILL PRIMARILY FOCUS
ALONG UPSLOPE MAUKA AND HIGHER TERRAIN WITH AFTERNOON HEATING
INTRODUCING ISOLATED LEEWARD SHOWERS. HIGHER CHANCES FOR MORE
FREQUENT RAIN EPISODES WILL OCCUR FROM FRIDAY INTO EARLY NEXT WEEK
ACROSS BETTER WINDWARD EXPOSURES.
DISCUSSION
A TRANQUIL, DRY MORNING ACROSS THE ISLANDS UNDER PARTIALLY CLEAR
SKIES AND LIGHT, VARIABLE BREEZES. WATER VAPOR IMAGERY IS EVIDENCE
THAT MOISTURE LEVELS ARE NEAR TO SLIGHTLY BELOW NORMAL BY SEASONAL
STANDARDS. WEAK TROUGHING LOCATED A FEW HUNDRED MILES NORTHEAST
OF THE STATE WILL LIKELY PROVIDE JUST ENOUGH INSTABILITY TO GO
WITH LOW END MODERATE RAIN CHANCES TODAY AND TONIGHT. EARLY DAY
WARMING UNDER MAINLY CLEAR SKIES WILL INITIATE THICKER CLOUDS AND
INCREASE SCATTERED SHOWERS OVER LEEWARD BIG ISLAND'S KONA REGION.
TRADES WILL RETURN TODAY BUT LIKELY STILL BE WEAK ENOUGH FOR
LOCALIZED SEA BREEZES TO DEVELOP AND BECOME THE DOMINANT FLOW
PATTERN. EARLY DAY SUN ON LEEWARD SLOPES, WITH SEA BREEZES
DRAWING UP HIGHER MOISTURE, WILL INCREASE LEEWARD ISOLATED
SHOWERS.
ON THE SYNOPTIC SCALE, HAWAII LIES WITHIN A HEIGHT WEAKNESS
REGION BETWEEN TWO SURFACE HIGH PRESSURE SYSTEMS...ONE FAR
NORTHWEST OF THE ISLANDS AND THE OTHER FAR NORTHEAST OF THE STATE.
THIS HAS CREATED A RELAXED SURFACE PRESSURE GRADIENT AND
MAINTAINED LOCALIZED SEA BREEZES DURING THE DAY FOLLOWED BY
NOCTURNAL DRAINAGE OR LAND BREEZES. THE PRESENCE OF A NORTHEAST
SURFACE TROUGH, WITH APPROACHING WEAK MID TO UPPER LEVEL TROUGHING
FROM THE NORTHWEST WITHIN A SOMEWHAT MOISTENED ENVIRONMENT, WILL
ENSURE THICKENED MAUKA CLOUDS AND MORE FREQUENT PRECIPITATION
WITHIN HIGHER ELEVATIONS. TOMORROW WILL BE ANOTHER PARTLY CLOUDY
DAY WITH THICKER CLOUDS AND MORE FREQUENT SHOWERS BEING CONFINED
TO WINDWARD UPSLOPE REGIONS AND HIGHER TERRAIN. WHILE FEELING A
TOUCH MORE HUMID DUE TO THE LACK OF MODERATE TRADES, THICKER CLOUD
COVER SHOULD KEEP MANY LOCALES IN THE MID TO UPPER 70S FOR THE
MAJORITY OF THE AFTERNOON. HIGH PRESSURE TO THE NORTHWEST WILL
MOVE ACROSS TO THE NORTH THE NEXT COUPLE OF DAYS. THIS WILL ASSIST
IN TIGHTENING UP THE PRESSURE GRADIENT OVER THE ISLANDS AND
STRENGTHENING TRADE WINDS. TRADES WILL GRADUALLY MAKE THEIR RETURN
TOMORROW AND STRENGTHEN TO MORE MODERATE MAGNITUDES THIS WEEKEND.
OVERALL TROUGHING WILL LIFT NORTHEAST OF THE STATE GOING INTO THE
EARLY PART OF NEXT WEEK. A GENERAL WEAK TROUGHING PATTERN WILL
HANG OVER THE STATE THROUGH MONDAY. RIBBONS OF HIGHER MOISTURE
MOVING IN ON MORE ESTABLISHED TRADES IN A DEEPER BOUNDARY LAYER
WILL PROMOTE THE INCREASED FREQUENCY OF LIGHT TO MODERATE
PRECIPITATION, ESPECIALLY OVER TRADITIONALLY MORE WET AREAS SUCH
AS KAUAI AND OAHU'S HIGHER ELEVATIONS, EASTERN MAUI COUNTY AND
WINDWARD BIG ISLAND. MORE ROBUST RIDGING IS FORECAST TO EXPAND IN
FROM THE WEST EARLY NEXT WEEK. THIS WILL PROVIDE GREATER STABILITY
IN TANDEM WITH A RELATIVELY DRIER ATMOSPHERE. THUS, OVERALL
STATEWIDE SHOWER ACTIVITY WILL BE ON THE DECLINE GOING INTO THE
MIDDLE OF NEXT WEEK.
AVIATION
LIGHT TO MODERATE TRADES GRADUALLY BUILD BACK ACROSS THE AREA
TODAY, RESULTING IN CLOUDS AND SHOWER DEVELOPMENT ALONG WINDWARD
AND MAUKA AREAS. MVFR CONDITIONS ARE POSSIBLE IN ANY SHOWER
ACTIVITY. OTHERWISE, VFR CONDITIONS PREVAIL.
NO AIRMETS ARE IN EFFECT.
MARINE
A WEAK TROUGH RESIDING NORTHEAST OF THE ISLANDS WILL KEEP TRADE
WINDS LIGHT TO LOCALLY MODERATE ACROSS ALL LOCAL WATERS TODAY INTO
FRIDAY. BY THIS WEEKEND, A SURFACE RIDGE BUILDING NORTHWEST OF
THE STATE WILL BRING A RETURN OF MODERATE TO LOCALLY FRESH TRADES.
A SMALL CRAFT ADVISORY MAY BE NEEDED FOR THE TYPICAL WINDY WATERS
SURROUNDING MAUI AND THE BIG ISLAND BY EARLY NEXT WEEK LATE AS
THE HIGH EXPANDS EASTWARD.
A MODERATE, LONG PERIOD, NORTHWEST SWELL IS FILLING IN ACROSS THE
LOCAL WATERS, AS NOTED ON THE LATEST HANALEI BUOY OBSERVATIONS.
THIS SWELL SHOULD PEAK LATER TODAY AND BRING ELEVATED SURF ALONG
NORTH AND WEST FACING BEACHES, JUST SHY OF ADVISORY LEVELS. EXPECT
A GRADUAL DECLINE TO SWELL AND SURF FRIDAY INTO THE WEEKEND.
A SMALL, LONG-PERIOD, SOUTH SWELL WILL CONTINUE TO FILL IN TODAY.
THIS SWELL SHOULD PROVIDE A SMALL BUMP IN SOUTH SHORE SURF
THROUGH THE END OF THE WEEK.
SURF ALONG EAST FACING SHORES WILL REMAIN BELOW NORMAL DURING THE
NEXT SEVERAL DAYS DUE TO THE LACK OF STRONG TRADES OVER AND
UPSTREAM OF THE ISLANDS. EAST SHORE SURF WILL GRADUALLY INCREASE INTO
THE WEEKEND AS TRADES MAKE A SLOW RETURN.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...BLOOD
AVIATION...PIERCE
MARINE...THOMAS
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