Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 290630
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST SUN DEC 28 2014

.SYNOPSIS...
DRY...STABLE...AND COOL CONDITIONS WILL PERSIST THROUGH MONDAY AS
NORTHEASTERLY WINDS WEAKEN AND SHIFT OUT OF THE SOUTHEAST BY LATE
MONDAY. A FRONT WILL SWEEP DOWN THE ISLAND CHAIN ON TUESDAY AND
TUESDAY NIGHT...BRINGING GUSTY WINDS WITH ONLY MODEST RAINFALL. A
BRIEF PERIOD RATHER DRY NORTHERLY FLOW IS EXPECTED WEDNESDAY INTO
THURSDAY FOLLOWED BY UNSETTLED WEATHER THURSDAY NIGHT AND SATURDAY.

&&

.DISCUSSION...
VERY DRY...STABLE...AND COOL CONDITIONS WILL CONTINUE THROUGH MONDAY
NIGHT AS WINDS WEAKEN AND SHIFT. RIDGING ALOFT WILL HOLD THROUGH
MONDAY AS SURFACE HIGH PRESSURE PASSES JUST NORTH OF THE ISLANDS.
AFTERNOON SOUNDINGS SHOWED PRECIPITABLE WATER VALUES AT NEARLY 50
PERCENT OF NORMAL AROUND 0.6 OF AN INCH AND A STRONG INVERSION DOWN
AT 4000 FT. EXPECT LITTLE TO NO RAINFALL STATE-WIDE THROUGH MONDAY
NIGHT AS THESE VERY DRY AND STABLE CONDITIONS HOLD...AND OVERNIGHT
LOW TEMPS WILL DIP INTO THE UPPER 50/S TO LOWER 60/S NEAR SEA LEVEL.
MODERATE NORTHEASTERLY SURFACE WINDS WILL WEAKEN SHIFT OUT OF THE
EAST BY MONDAY MORNING AS THE SURFACE HIGH TO OUR NORTHWEST PASSES
NORTH OF THE ISLANDS. WINDS WILL WEAKEN FURTHER AND VEER OUT OF THE
SOUTHEAST LATE IN THE AFTERNOON THEN SOUTHERLY OVERNIGHT AS A FRONT
APPROACHES FROM THE NORTHWEST.

A FRONT WILL SWEEP DOWN THE ISLAND CHAIN TUESDAY AND TUESDAY NIGHT.
A VERY STRONG WEST TO EAST FLOWING JET STREAM ALOFT OVER THE
WESTERN PACIFIC WILL DRIVE A SHARP AND DEEP UPPER LEVEL TROUGH OVER
THE ISLANDS ON TUESDAY. FORECAST MODELS ARE ADVERTISING A SURFACE
LOW DEVELOPING ABOUT 300 MILES NORTH OF THE ISLANDS AT THIS TIME
WITH A SURFACE FRONT SWEEPING DOWN ACROSS THE STATE. THE STRONGEST
DYNAMICS WILL PASS JUST NORTH OF THE ISLANDS...AND MOISTURE OVER THE
ISLANDS WILL BE SOMEWHAT LIMITED...PROBABLY UP TO AROUND SEASONAL
NORMAL ALONG THE FRONT. AS A RESULT...FLOODING RAINFALL AND
THUNDERSTORMS NOT EXPECTED...BUT WINDS WILL LIKELY BECOME BREEZY AND
GUSTY JUST AHEAD OF AND BEHIND THE FRONT. AREAS ON THE SMALLER
ISLANDS THAT ARE PRONE TO DOWNSLOPING SOUTHWESTERLY WINDS SHOULD
SEE SOME GUSTS ABOVE 40 MPH...THOUGH WE ARE NOT EXPECTING WIND
ADVISORY CONDITIONS AT THIS TIME. HOWEVER...LOOK FOR ANOTHER BOUT
OF VERY STRONG WINDS ON THE SUMMITS OF THE BIG ISLAND AND POSSIBLY
HALEAKALA.

DRY POST-FRONTAL NORTHERLY WINDS ARE IN STORE FOR WEDNESDAY AS THE
FRONT PUSHES NEAR OR JUST EAST OF THE BIG ISLAND. WINDS WILL
DECREASE ON NEW YEARS EVE.

ACTIVE WEATHER IS POSSIBLE FOR THURSDAY NIGHT THROUGH SATURDAY. THE
STRONG WESTERN PACIFIC JET STREAM IS EXPECTED TO DROP ANOTHER...
STRONGER SHORTWAVE ALOFT INTO THE UPPER TROUGH THAT MOVED OVER THE
STATE A COUPLE OF DAYS PRIOR. AT THIS TIME...IT IS UNCLEAR HOW MUCH
MOISTURE WILL BE AVAILABLE...BUT GIVEN STRONG MID TO UPPER LEVEL
INSTABILITY...ACTIVE WEATHER IN THE FORM OF THUNDERSTORMS IS
POSSIBLE.

&&

.AVIATION...
VFR WILL PREVAIL. AREAS OF VFR CIGS FORMING OVER WINDWARD SLOPES
TONIGHT...BUT LITTLE TO NO RAINFALL OR VIS RESTRICTIONS ARE IN
STORE.

&&

.MARINE...
SURF HEIGHTS ALONG NORTH-FACING SHORES ARE EXPECTED TO REMAIN BELOW
ADVISORY LEVELS THROUGH TUESDAY. A NEW AND LARGER NORTHWEST SWELL IS
EXPECTED TO BOOST SURF HEIGHTS TO NEAR ADVISORY LEVELS FROM TUESDAY
THROUGH THURSDAY.

WIND SPEEDS AND COMBINED SEAS ARE EXPECTED TO REMAIN THE BELOW SMALL
CRAFT ADVISORY /SCA/ THRESHOLD THROUGH MONDAY NIGHT. SCA WINDS ARE
POSSIBLE ALONG AND BEHIND A FRONT ON TUESDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

WROE








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