Area Forecast Discussion
Issued by NWS Honolulu, HI

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FXHW60 PHFO 281750 AAA
AFDHFO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HONOLULU HI
750 AM HST WED JAN 28 2015

.UPDATE...
INCEASED CLOUD COVER TODAY FOR ALMOST ALL PARTS OF THE STATE GIVEN
THE CURRENT SATELLITE AND WEATHER OBSERVATIONS. SLIGHTLY BOOSTED
CHANCE FOR SHOWERS MAINLY FOR THE LEEWARD AREAS FOR TODAY DUE TO
LIGHT SOUTHEAST FLOW WHICH WILL INDUCE SEA BREEZES OVER THE STATE
LATER TODAY...ALONG WITH SCATTERED SHOWERS PRESENT ON RADAR THIS
MORNING.


&&

.SYNOPSIS...
A FRONT APPROACHING THE STATE WILL SPREAD LIGHT RAIN AND WEAK
NORTHWEST WINDS OVER THE ISLANDS FROM THURSDAY INTO FRIDAY. LIGHT
TRADE WINDS WILL RETURN...AND CONDITIONS WILL DRY...SLOWLY OVER THE
WEEKEND. A STRONGER FRONT MAY REACH THE STATE EARLY NEXT WEEK.

&&

.PREV DISCUSSION.../ISSUED 400 AM HST WED JAN 28 2015/

OBSERVATIONS AROUND THE MAIN HAWAIIAN ISLANDS REPORTED LIGHT WINDS
OVERALL WITH A STRONG HINT OF LAND BREEZES...WHILE BUOYS FURTHER
OFFSHORE...AND SATELLITE-BASED SCATTEROMETER DATA...SHOWED
INCREASINGLY SOUTHEASTERLY FLOW. ALOFT...BROAD BUT FLAT RIDGING
STILL LINGERED OVER THE STATE...THOUGH A BROADER TROUGH SLOWLY
DENTED THE RIDGE FROM THE WEST-NORTHWEST. ENOUGH SUBSIDENCE WAS
PRESENT TO REINFORCE THE INVERSION AT NEAR ITS USUAL HEIGHT.

THE AIR MASS REMAINED SOMEWHAT DRY...BUT SATELLITE ESTIMATES
SUGGESTED GRADUAL MOISTENING DURING THE PAST 36 HOURS OR SO.
STRATOCUMULUS CLOUDS SPREAD AROUND MOST OF THE ISLANDS FROM THE
NORTHEAST. ALTHOUGH THESE LOW CLOUDS STILL APPEARED MOSTLY STABLE
IN SATELLITE IMAGES...RADAR DATA SHOWED INCREASED SPECKLES OF
SHOWER ACTIVITY OVER THE WATER. WHERE THE LAND BREEZES
PERMITTED...SOME OF THESE SHOWERS MOVED ASHORE...DROPPING
ACCUMULATION OF SEVERAL HUNDREDTHS OF AN INCH IN PLACES.
THUS...CLOUD COVER...POPS...AND RELATED FIELDS HAVE BEEN INCREASED
FOR TODAY AND TONIGHT. WHILE THE RESULTING FORECAST WAS NOT
EXACTLY WET...IT CERTAINLY WAS LESS DRY THAN EARLIER THINKING HAD
ANTICIPATED.

GUIDANCE PREDICTED THE FEEBLE FRONT NOW APPROACHING FROM THE
NORTHWEST TO ADVANCE SOUTHEAST ACROSS THE STATE FROM THURSDAY INTO
FRIDAY. CONSENSUS PREDICTED LITTLE WATER VAPOR TO ACCOMPANY THE
FRONT...ALTHOUGH RECENT RUNS DID BOOST THEIR PREDICTIONS FROM
THURSDAY AFTERNOON ONWARD. THE BROAD MID-LEVEL TROUGH EXPANDING
SOUTHEAST OVER THE ISLANDS AT THE SAME TIME WILL PROVIDE MOST OF ITS
SUPPORT FURTHER TO THE NORTH...LIMITING ITS LOCAL INFLUENCE. THUS...
RELATIVELY LITTLE RAIN WILL ACCOMPANY THE FRONT...AND NORTHWEST
WINDS BEHIND IT SHOULD BE FAIRLY LIGHT AS WELL. LIGHT TRADE WINDS
WILL RECOVER GRADUALLY OVER THE WEEKEND. LINGERING MOISTURE WILL
CONTINUE TO SUPPORT DISORGANIZED...POSSIBLY DIURNAL...SHOWERS INTO
SUNDAY. THESE SHOWERS MAY WELL PRODUCE MORE RAIN THAN THE FRONT
ITSELF.

BY MONDAY...MOST SOLUTIONS PREDICTED A SECOND...STRONGER FRONT TO
APPROACH FROM THE NORTHWEST...TURNING WINDS SOUTHERLY AGAIN AHEAD OF
IT. GUIDANCE CONTINUED TO DISAGREE WITH RESPECT TO THE MOTION OF
MID-LEVEL LOWS NORTH OF THE STATE DURING THIS TIME. IF MOST TRACK
WELL NORTH...THEN ONLY WEAK AND BAGGY TROUGHING MAY BE PRESENT
NEARBY...GREATLY LIMITING SUPPORT FOR THE FRONT AT THE SURFACE. ON
THE OTHER HAND...SOME SOLUTIONS SUGGESTED A MORE SOUTHERLY TRACK FOR
THE LOWS...AND THUS MORE SIGNIFICANT SUPPORT. IN ANY CASE...
CONSENSUS PREDICTED MORE ABUNDANT WATER VAPOR ACCOMPANYING THIS
FRONT THAN THE FIRST ONE...SO AT LEAST THE POTENTIAL FOR WIDESPREAD
RAIN WILL BE PRESENT.

&&

.MARINE...
THE CURRENT NORTHWEST SWELL WILL DIMINISH BY THURSDAY. REINFORCING
SWELL FROM THE NORTHWEST WILL ARRIVE FRIDAY AND SATURDAY...WITH
THE SATURDAY SWELL LIKELY RESULTING IN ADVISORY-LEVEL SURF ALONG
NORTH FACING SHORES. THIS SWELL WILL GRADUALLY DIMINISH THROUGH
TUESDAY. COMBINED SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY OVER THE NEXT FEW DAYS.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 AM HST THURSDAY FOR NORTH AND WEST
FACING SHORES OF NIIHAU KAUAI AND OAHU...AND FOR NORTH FACING
SHORES OF MOLOKAI AND MAUI.

&&

$$

FOSTER



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