Area Forecast Discussion
Issued by NWS Honolulu, HI

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FXHW60 PHFO 270602
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST MON JAN 26 2015

.SYNOPSIS...
MODERATE TRADE WINDS WILL DIMINISH SLOWLY AND BECOME MORE SOUTHERLY
AS A WEAK FRONT APPROACHES THE STATE TONIGHT AND TUESDAY. FROM
THURSDAY INTO FRIDAY...THIS FRONT WILL SPREAD LIGHT RAIN AND WEAK
NORTHWEST WINDS ACROSS THE STATE. TRADE WINDS WILL RETURN...AND
CONDITIONS WILL DRY...SLOWLY OVER THE WEEKEND. ANOTHER FRONT MAY
APPROACH THE ISLANDS EARLY NEXT WEEK.

&&

.DISCUSSION...
OBSERVATIONS AROUND THE MAIN HAWAIIAN ISLANDS REPORTED MODERATE TO
LOCALLY STRONG TRADE WINDS BLOWING. BROAD RIDGING PREVAILED OVER THE
STATE ALOFT...STRENGTHENING THE INVERSION AT A FAIRLY TYPICAL
HEIGHT. THE AIR MASS WAS ON THE DRY SIDE OF USUAL...AND THE BULK OF
THE FRONTAL REMNANTS NOW WERE LOCATED TO THE SOUTH OF THE STATE...
BUT STABLE STRATOCUMULI PERSISTING UPWIND PROMISED TO SPREAD ASHORE
AGAIN ALONG WINDWARD SLOPES OVERNIGHT. THESE STABLE CLOUDS HAD THE
POTENTIAL TO PRODUCE MODERATELY WIDESPREAD DRIZZLE OR LIGHT RAIN...
BUT ACCUMULATION SHOULD REMAIN VERY MUCH ON THE LIGHT SIDE...AND
LIMITED ALMOST EXCLUSIVELY TO WINDWARD SLOPES.

GUIDANCE PREDICTED LITTLE CHANGE THROUGH THE NEXT DAY OR SO...BUT BY
WEDNESDAY WINDS WILL START TO WEAKEN AND TURN MORE SOUTHERLY AHEAD
OF A FEEBLE FRONT APPROACHING FROM THE NORTHWEST. THIS FEATURE
SHOULD MOVE SOUTHEAST ACROSS THE STATE FROM THURSDAY INTO FRIDAY.
CONSENSUS PREDICTED LITTLE WATER VAPOR TO ACCOMPANY THE FRONT...AND
A BROAD MID-LEVEL TROUGH EXPANDING SOUTHEAST OVER THE ISLANDS AT THE
SAME TIME WILL PROVIDE ONLY LIMITED SUPPORT. THUS...RELATIVELY
LITTLE RAIN WILL ACCOMPANY THE FRONT...AND NORTHWEST WINDS BEHIND IT
SHOULD BE FAIRLY LIGHT AS WELL. TRADE WINDS WILL RECOVER GRADUALLY
OVER THE WEEKEND...BUT LINGERING MOISTURE WILL CONTINUE TO SUPPORT
SHOWERS...PERHAPS PRODUCING MORE RAIN THAN THE FRONT ITSELF.

BY MONDAY...MOST SOLUTIONS PREDICTED A SECOND...STRONGER FRONT TO
APPROACH FROM THE NORTHWEST. GUIDANCE DISAGREED SOMEWHAT ABOUT HOW
MUCH SUPPORT THIS FEATURE WILL RECEIVE FROM ALOFT...BUT GENERALLY
PORTRAYED MUCH MORE ABUNDANT WATER VAPOR ACCOMPANYING IT. WINDS
SHOULD DIMINISH AND BECOME MORE SOUTHERLY AROUND THIS TIME...BUT
MODELS DIFFERED WITH RESPECT TO THE HOW SOON...OR IF...THIS SECOND
FRONT MAY REACH THE STATE.

&&

.AVIATION...
AIRMET SIERRA FOR MOUNTAIN OBSCURATION REMAINS IN EFFECT ACROSS
WINDWARD SECTIONS OF KAUAI AND THE BIG ISLAND. CEILINGS HAVE BEEN
RUNNING SOMEWHAT HIGHER AT VFR LEVELS IN THOSE AREAS RECENTLY...
AND THE AIRMET MAY BE DROPPED LATER TONIGHT.

AIRMET TANGO FOR LOW LEVEL TURBULENCE REMAINS IN EFFECT TO THE SOUTH
THROUGH WEST OF HIGHER TERRAIN ON MAUI AND THE BIG ISLAND. MODELS
SUGGEST THAT TRADE FLOW WILL WEAKEN ON TUESDAY...AND THIS AIRMET
WILL PROBABLY BE DROPPED THEN.

VFR CONDITIONS WILL PREVAIL ACROSS MOST AREAS OVERNIGHT AND TUESDAY.
WINDWARD SECTIONS MAY CONTINUE TO SEE SOME PERIODS OF MVFR
CONDITIONS ESPECIALLY OVERNIGHT INTO TUESDAY MORNING. HILO AND LIHUE
WILL BE THE TERMINALS MOST LIKELY AFFECTED. LANAI COULD SEE PERIODS
OF MVFR CIGS TUESDAY AFTERNOON.

&&

.MARINE...
LOCALLY STRONG TRADE WINDS DRIVEN BY HIGH PRESSURE PASSING NORTHEAST
OF THE STATE WILL KEEP SMALL-CRAFT-ADVISORY CONDITIONS IN THE
TYPICAL WINDY ZONES AROUND MAUI COUNTY AND THE BIG ISLAND THROUGH
TONIGHT. WIND SPEEDS SHOULD DROP OFF STARTING TUESDAY MORNING AS THE
HIGH PRESSURE SHIFTS TOWARD THE NORTHEAST.

THE NEXT INCOMING NORTHWEST SWELL LIKELY WILL PRODUCE ADVISORY-LEVEL
SURF HEIGHTS ALONG NORTH- AND WEST-FACING SHORES FROM TUESDAY NIGHT
THROUGH THURSDAY. ANOTHER LARGE NORTHWEST SWELL IS EXPECTED TO
ARRIVE FRIDAY...AND THEN CONTINUE THROUGH SUNDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 AM HST TUESDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.

&&

$$

DISCUSSION...RYSHKO
AVIATION...JACOBSON




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