Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 211952 RRA
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST SUN SEP 21 2014

.SYNOPSIS...
HUMID CONDITIONS UNDER LIGHT WINDS WILL CONTINUE TODAY...WITH
ANOTHER ROUND OF AFTERNOON CLOUDS AND SPOTTY SHOWERS DUE. SOME
RELIEF IS ON THE WAY...AS TRADES WILL GRADUALLY STRENGTHEN MONDAY
AND TUESDAY. SHOWERS BECOME FOCUSED ACROSS WINDWARD SLOPES...THOUGH
CLOUDS AND A FEW SHOWERS WILL CONTINUE TO DEVELOP OVER LEEWARD
TERRAIN EACH AFTERNOON. A WETTER TRADE WIND PATTERN IS EXPECTED
DURING THE SECOND HALF OF THE WEEK.

&&

.DISCUSSION...
HUMID CONDITIONS UNDER LIGHT WINDS WILL PERSIST TODAY. A NEARLY
STATIONARY REMNANT FRONT 400 MILES NORTH OF KAUAI AND A WEAK SURFACE
TROUGH ABOUT 250 MILES NORTH OF MAUI ARE KEEPING THE BACKGROUND
TRADE WIND FLOW WEAK. MEANWHILE...THE LOWER ATMOSPHERE REMAINS
RATHER MOIST WITH SURFACE DEW POINTS GENERALLY RUNNING IN THE LOW TO
MID 70/S. THE ELEVATED MOISTURE IS POOLED TO THE EAST OF A SURFACE
TROUGH SITTING ABOUT 275 MILES SOUTHWEST OF THE STATE. UNDER THESE
CONDITIONS...ANOTHER UNCOMFORTABLY HUMID DAY IS IN STORE. DAYTIME
HIGHS WILL MOSTLY CLIMB TO AROUND 90...BUT ELEVATED DEW POINTS WILL
MAKE IT FEEL LIKE MID 90/S OUT THERE. WIDESPREAD DAYTIME SEA BREEZES
WILL EASILY OVERPOWER THE WEAKENED TRADE WIND FLOW... LEADING TO
AFTERNOON CLOUDS AND SPOTTY SHOWERS OVER THE ISLANDS. SOME OF
SHOWERS COULD BE BRIEFLY HEAVY ON THE BIG ISLAND...AND A SHARP UPPER
TROUGH SITTING OVERHEAD COULD TRIGGER AN ISOLATED THUNDERSTORM ON
AND SOUTH OF THE BIG ISLAND AS WELL TODAY.

TRADE WINDS WILL BUILD ON MONDAY AND TUESDAY...BRINGING SOME RELIEF.
LOW LEVEL MOISTURE WILL INITIALLY DECREASE AS SLIGHTLY DRIER AIR
MOVES IN BEHIND THE DEPARTING SURFACE TROUGH TO THE SOUTHWEST. EVEN
THOUGH THE DEW POINT TEMPS WILL ONLY BE DROPPING A COUPLE OF
DEGREES...THE COMBINATION SLIGHTLY DRIER CONDITIONS AND BUILDING
GENTLE TRADE WINDS WILL BE NOTICEABLE. LEEWARD AREAS WILL REMAIN
HOT...WITH SHELTERED AREAS NEAR TERRAIN EXPERIENCING SOME AFTERNOON
CLOUDS AND A SLIGHT CHANCE OF SHOWERS ON MONDAY. TRADES WILL
STRENGTHEN TO MODERATE LEVELS ON TUESDAY...AND A TYPICAL...
WINDWARD-FOCUSED SHOWER REGIME WILL PREVAIL.

A WET TRADE WIND RAINFALL PATTERN IS DUE DURING THE SECOND PART OF
THE WEEK. FORECAST MODELS ARE SHOWING A BAND OF REMNANT FRONTAL
MOISTURE SAGGING SOUTHWARD OVER THE SMALLER ISLANDS WEDNESDAY AND
STALLING THURSDAY. INITIAL INDICATIONS ARE THAT THIS BAND COULD
STICK
AROUND INTO NEXT WEEKEND...KEEPING MAINLY WINDWARD AREAS WET. FOR
NOW...THE FORECAST BROAD BRUSHES WET CONDITIONS...BUT LOOK FOR FINE
TUNING AS WE GET A HANDLE ON WHICH ISLANDS WILL BE MOST AFFECTED BY
THE MOISTURE BAND.

&&

.AVIATION...
BACKGROUND FLOW WILL REMAIN FAIRLY WEAK TODAY. MOSTLY CLEAR SKIES
OVER THE ISLANDS THIS MORNING WILL BEGIN TO CLOUD UP LATE THIS
MORNING AND EARLY THIS AFTERNOON AS SEA BREEZES ARE EXPECTED TO
DEVELOP. FOR THE SMALLER ISLANDS...CLOUDS AND SHOWERS WILL CARRY
PERIODS OF TEMPO MVFR WITH POSSIBLE BRIEF PERIODS ISOL IFR WITH
CLOUD TOPS REACHING ABOVE 15KFT.

A WEAK DISTURBANCE SW OF THE STATE IS LIKELY TO ENHANCE CLOUDS AND
SHOWERS OVER THE BIG ISLAND...CARRYING MVFR WITH POSSIBLE IFR
CONDITIONS. THERE IS A SLIGHT CHANCE FOR THUNDERSTORMS TO DEVELOP
THIS AFTERNOON...WITH CB TOPS REACHING FL350.

ON ALL ISLANDS...ACTIVITY SHOULD BEGIN TO DIMINISH WITH SUNSET AND
ONLY BRIEF MVFR CONDITIONS IN PASSING SHOWERS WILL REMAIN...MAINLY
FOR WINDWARD AND MAUKA AREAS.

&&

.MARINE...
NO ISSUES IN THE SHORT TERM. INCREASING TRADE WINDS WILL BRING
BORDER LINE SMALL CRAFT ADVISORY WINDS TO THE TYPICALLY WINDY WATERS
AROUND THE BIG ISLAND AND MAUI COUNTY STARTING TUESDAY. SURF WILL
REMAIN AROUND BACKGROUND LEVELS THROUGH MUCH OF THE WEEK. A
SLIGHTLY HIGHER SWELL OF AROUND 4 FEET IS EXPECTED FROM THE NNE
THURSDAY THROUGH SATURDAY. A MODERATE SSW IS DUE NEXT WEEKEND.

&&

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

&&

$$

DISCUSSION/MARINE...REYNES
AVIATION...BEDAL





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