710
FXHW60 PHFO 160143
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
343 PM HST TUE APR 15 2025
SYNOPSIS
EAST SOUTHEAST WINDS WILL EASE TONIGHT, WITH DAYTIME SEA BREEZE
AND NIGHTTIME LAND BREEZE PATTERN FROM WEDNESDAY AND CONTINUING
THROUGH FRIDAY. A DISTURBANCE ALOFT MOVING OVER THE ISLANDS COULD
BRING SOME HEAVIER SHOWERS AND THUNDERSTORMS THURSDAY AND FRIDAY.
A RETURN TO A MORE TYPICAL TRADE WIND REGIME ALONG WITH A GRADUAL
INCREASE IN TRADE WIND SPEEDS WILL BE POSSIBLE OVER THE WEEKEND
INTO EARLY NEXT WEEK.
DISCUSSION
AT THE SURFACE, A 1025 MB SURFACE HIGH IS CENTERED FAR NORTHEAST
OF HAWAII DRIVING GENTLE TO MODERATE EAST SOUTHEAST WINDS ACROSS
THE AREA. AN APPROACHING COLD FRONT IS LOCATED AROUND 650 MILES
NORTHWEST OF KAUAI, WHILE AN APPROACHING WEAK TROUGH IS LOCATED
300 MILES EAST OF THE BIG ISLAND.
WINDS WILL TAPER OFF AND VEER SOUTHEASTERLY TONIGHT AS THE FRONT
AND TROUGH CONVERGE TOWARDS THE ISLANDS. LAND BREEZES WILL KEEP
MOST OF THE ASSOCIATED CLOUDS AND SHOWERS WITH BOTH FEATURES
OFFSHORE, BUT AS SEA BREEZES BUILD IN DURING THE DAY WEDNESDAY,
CLOUDS AND SHOWERS WILL FOCUS OVER THE ISLANDS.
AN UPPER TROUGH WILL DIG SOUTHEASTERLY ACROSS THE ISLANDS LATE
WEDNESDAY NIGHT THROUGH FRIDAY. THE FRONT WILL MERGE WITH THE
SURFACE TROUGH CREATING A POOL OF LOW LEVEL MOISTURE OVER THE
STATE. AS THE UPPER TROUGH MOVES THROUGH, 500 MB TEMPERATURES
WILL LOWER TO AROUND -12 TO -13C AND PRECIPITABLE WATER VALUES
WILL INCREASE FROM AROUND 1.2 CURRENTLY TO AROUND 1.5 INCHES ON
THURSDAY. THIS WILL LIKELY RESULT IN SOME HEAVIER SHOWERS AND A
SLIGHT CHANCE OF THUNDERSTORMS THURSDAY AND FRIDAY (MORE OF THE
FOCUS WILL BE ON BIG ISLAND FRIDAY). POSSIBLE MINOR PONDING/FLOODING
RESULTING FROM THIS RAINFALL, BUT HOLDING OFF WITH A FLOOD WATCH
FOR NOW GIVEN THE BRIEF WINDOW OF UPPER LEVEL FORCING. SNOW WILL
BE POSSIBLE ON THE BIG ISLAND SUMMITS THURSDAY THROUGH FRIDAY AND
WILL CONSIDER A WINTER WEATHER ADVISORY. THE UPPER TROUGH WILL
WEAKEN AND SLIDE EAST OF THE STATE BY LATE FRIDAY RETURNING TO
MORE A MORE STABLE ATMOSPHERE.
LIGHT TO MODERATE TRADE WINDS WILL GRADUALLY NOSE IN OVER THE
WEEKEND, WITH LIKELY WETTER-THAN-NORMAL WINDWARD AND MAUKA SHOWERS
BEFORE THE AREA OF MOISTURE IS CLEARED TO THE WEST. A MORE
TYPICAL TRADE WIND PATTERN MAY SLOWLY RETURN OVER THE WEEKEND INTO
EARLY NEXT WEEK.
AVIATION
MODERATE TRADES WILL GRADUALLY EASE INTO TOMORROW AND USHER IN
SHRA AND LOW CIGS TO WINDWARD AND MAUKA LOCATIONS. HOWEVER, WINDS
MAY BEGIN TO BE LIGHT ENOUGH TO SEE SOME SEA BREEZE DEVELOPMENT
THAT WOULD BRING SOME ISOL SHRA TO LEEWARD AREAS. MVFR CONDS WILL
BE POSSIBLE IN ANY SHRA, BUT VFR SHOULD PREVAIL.
WHILE THE ONGOING ERUPTION OF KILAUEA IS CURRENTLY PAUSED, THERE
IS DEGASSING OCCURRING. THIS COULD CAUSE SOME HAZY CONDS ACROSS
THE ISLANDS. IT IS NOT ENOUGH TO IMPACT VSBYS AT THIS TIME AND NOT
CURRENTLY IN ANY TAFS BUT WAS WORTH A MENTION.
NO AIRMETS IN EFFECT.
MARINE
TRADE WINDS WILL CONTINUE TO DECLINE AND SHIFT OUT OF THE
SOUTHEAST THROUGH WEDNESDAY AS AN ADVANCING FRONT WEAKENS THE
SURFACE RIDGE NORTH OF THE STATE. EASTERLY TRADE WINDS ARE
CURRENTLY AT MODERATE TO FRESH STRENGTH, AND A MORNING ASCAT PASS
CONFIRMED THAT WINDS AROUND THE BIG ISLAND HAVE EASED ENOUGH TO
ALLOW THE SMALL CRAFT ADVISORY (SCA) TO BE DROPPED. BY WEDNESDAY
MORNING, GENTLE TO MODERATE EAST TO SOUTHEASTERLY WINDS WILL
PREVAIL STATEWIDE, FOLLOWED BY A BRIEF PERIOD OF VARIABLE WINDS
AROUND KAUAI AND POSSIBLY OAHU WEDNESDAY AFTERNOON AND EVENING.
GENTLE TO LOCALLY FRESH EAST TO EAST-SOUTHEAST TRADE WINDS WILL
DOMINATE THURSDAY AND FRIDAY, AND A SLIGHT INCREASE IN WINDS MAY
REQUIRE THE SCA TO BE REISSUED AROUND THE BIG ISLAND AND MAUI
DURING THE WEEKEND.
AS TRADES DIMINISH, CHANCES FOR HEAVY SHOWERS AND THUNDERSTORMS
WILL INCREASE. THE MAIN THREAT WILL DEVELOP AROUND KAUAI AND OAHU
LATE WEDNESDAY NIGHT, SLOWLY SPREAD TO THE ENTIRE ISLAND CHAIN
THURSDAY, THEN DIMINISH FROM WEST TO EAST ON FRIDAY.
SMALL SURF ALONG EXPOSED NORTH AND WEST FACING SHORES WILL
CONTINUE TO LOWER THROUGH WEDNESDAY AS A NORTHWEST SWELL FADES. A
MEDIUM PERIOD NORTH-NORTHWEST SWELL WILL BUILD THURSDAY AND WILL
PUSH SURF NEAR HIGH SURF ADVISORY LEVELS DURING THE PEAK THURSDAY
NIGHT AND EARLY FRIDAY. THIS SWELL WILL STEADILY DECLINE AND SHIFT
OUT OF THE NORTH LATER FRIDAY AND THE WEEKEND.
SURF ALONG EAST FACING SHORES WILL TREND DOWN TONIGHT AS TRADES
EASE. EAST SHORE SURF WILL REMAIN BELOW APRIL AVERAGE THROUGH AT
LEAST SATURDAY AND WILL LIKELY RISE TO AROUND AVERAGE ON SUNDAY.
SURF ALONG SOUTH FACING SHORES WILL REMAIN SMALL THROUGH MOST OF
THE WEEK, WITH MAINLY OVERLAPPING BACKGROUND SOUTH SWELLS MOVING
THROUGH. A LARGER PULSE OF SOUTH-SOUTHWEST SWELL MAY ARRIVE
TUESDAY.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...FOSTER
AVIATION...WALSH
MARINE...WROE
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