Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 281930
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST SUN DEC 28 2014

.SYNOPSIS...
LIGHT WINDS AND DRY STABLE CONDITIONS WILL PERSIST ACROSS THE AREA
FOR THE NEXT DAY OR SO. A FRONT WILL PASS DOWN THE ISLAND CHAIN
TUESDAY AND WEDNESDAY...BRINGING LIMITED RAINFALL...WHILE ANOTHER
BOUT OF UNSETTLED WEATHER IS EXPECTED BY NEXT WEEKEND.

&&

.DISCUSSION...
A RIDGE OF HIGH PRESSURE NUDGING EASTWARD HAS SETTLED OVER AND NORTH
OF THE MAIN HAWAIIAN ISLANDS...BRINGING A COMBINATION OF
DRYNESS...STABLE CONDITIONS AND A GRADUAL RETURN OF NORTHEAST TRADE
WINDS. OVERNIGHT SOUNDINGS SHOW STRONG INVERSIONS NEAR 3700 FEET AND
BETWEEN 0.6 AND 0.7 INCHES OF PRECIPITABLE WATER...LIKELY EXPLAINING
THE LACK OF SHOWERS NOTED ON RADAR THIS MORNING. SATELLITE LOOP
SHOWS CLOSED-CELL STABLE LOW CLOUDS STREAMING ACROSS LOCAL WATERS
FROM THE NORTH NORTHEAST...WITH MOST AREAS OF THE ISLANDS BENEATH
CLEAR SKIES.

MODERATE NORTHEAST TRADES WILL WEAKEN AND BECOME SOUTHERLIES BY LATE
MONDAY AS A FRONT APPROACHES THE MAIN ISLANDS FROM THE NORTHWEST.
THOUGH MODELS VARY SLIGHTLY WITH TIMING...WE EXPECT THIS FRONT WILL
REACH KAUAI AROUND MIDDAY TUESDAY...THEN MOVE SOUTHEAST DOWN THE
ISLAND CHAIN UNTIL IT REACHES THE BIG ISLAND WEDNESDAY MORNING.
CLOUDS AND SHOWERS WILL INCREASE ALONG AND NEAR THE FRONT...BUT NO
HEAVY RAINFALL IS EXPECTED. MODERATE NORTHWEST WINDS WILL ALSO
ACCOMPANY FRONTAL PASSAGE. FOLLOWING GFS...WE FORECAST THE FRONT
WILL STALL NEAR THE BIG ISLAND AND WASH OUT THROUGH THURSDAY. WEAK
RIDGING WILL MOVE IN AS THE FRONT PASSES...CAUSING WINDS TO DECREASE
AFTER FRONTAL PASSAGE ACROSS MOST AREAS WEDNESDAY. THIS MEANS THAT
THERE MAY BE LOW VISIBILITIES NEW YEARS EVE ACROSS LOCAL AREAS WITH
HIGH FIREWORKS ACTIVITY DUE TO POOR DISPERSAL.

THE WEAK POST-FRONTAL RIDGE IS FORECAST TO DRIFT SOUTHWARD OVER THE
ISLANDS THURSDAY AND FRIDAY...KEEPING THE NORTH TO NORTHWEST WINDS
LIGHT AS THE WEEKEND APPROACHES. MODELS SHOW UNSETTLED WEATHER
FORMING OVER AND NEAR THE MAIN ISLANDS FRIDAY THROUGH POSSIBLY
SATURDAY AS UPPER TROUGHING STRENGTHENS AND DESTABILIZES OUR
AIRMASS. HOWEVER...MODELS ARE A BIT UNCLEAR WHAT FORM THIS UNSETTLED
WEATHER WILL TAKE SINCE IT DOES NOT LOOK LIKE A TYPICAL FRONTAL
PASSAGE AT THIS POINT.

WINDS ACROSS THE HIGHEST SUMMITS ON MAUI AND THE BIG ISLAND REMAIN
HIGH...AND WIND ADVISORIES ARE IN EFFECT THERE. UPPER ELEVATION
WINDS SHOULD DECREASE BY THIS EVENING.

&&

.AVIATION...
NORTHERLY WINDS WILL VEER MORE NORTHEASTERLY TODAY. THE STRONG MID
LEVEL WINDS OVER THE SUMMITS WILL BEGIN TO WEAKEN TODAY. THE AIRMET
FOR TURBULENCE OVER AND SOUTH OF SUMMITS WILL LIKELY BE CANCELED BY
THIS AFTERNOON. OTHERWISE...VFR WILL PREVAIL UNDER A DRY AND STABLE
ATMOSPHERE.

&&

.MARINE...
SURF HEIGHTS ALONG NORTH-FACING SHORES ARE EXPECTED TO REMAIN BELOW
ADVISORY LEVELS THROUGH TUESDAY. CURRENTLY...THE MODERATE NORTHWEST
SWELL IS RIDING CLOSE TO ADVISORY LEVEL AND WILL BE MONITORED
CLOSELY. THERE COULD BE SOME CONTRIBUTION FROM A SMALLER NORTH
SWELL...IN ADDITION TO WAVES PRODUCED BY THE NORTHERLY WINDS...IN
MAKING SURF VERY CLOSE TO ADVISORY LEVEL. THIS SWELL IS EXPECTED TO
START LOWERING THIS AFTERNOON. A NEW AND LARGER NORTHWEST SWELL IS
EXPECTED TO BOOST THE SURF UP TO NEAR ADVISORY LEVELS FROM TUESDAY
THROUGH THURSDAY.

OVER THE COASTAL WATERS...WIND SPEEDS AND COMBINED SEAS ARE EXPECTED
TO REMAIN BELOW THE THRESHOLD FOR A SMALL CRAFT ADVISORY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FOR MAUNA LOA...MAUNA KEA AND HALEAKALA SUMMIT AREAS
UNTIL 6 PM HST TODAY.

&&

$$

DISCUSSION AND MARINE...POWELL
AVIATION...EATON






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