Area Forecast Discussion
Issued by NWS Honolulu, HI

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FXHW60 PHFO 230630
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST SAT NOV 22 2014

.SYNOPSIS...
LIGHTER TRADES WILL ALLOW ANOTHER ROUND OF SEA BREEZES AND A FEW
SHOWERS SUNDAY AFTERNOON.  A RELATIVELY WEAK FRONT IS EXPECTED TO
MOVE ACROSS THE ISLAND CHAIN SUNDAY NIGHT THROUGH MONDAY...BRINGING
A BRIEF ROUND OF SHOWERS. COOLER AND DRIER AIR WILL FILTER INTO THE
AREA FROM THE NORTH IN THE WAKE OF THE FRONT...WITH WINDS BECOMING
NORTHEASTERLY BY TUESDAY. BREEZY TRADE WINDS WILL THEN PERSIST INTO
NEXT WEEKEND...DELIVERING A FEW BRIEF WINDWARD AND MAUKA SHOWERS.

&&

.DISCUSSION...
A BROAD HIGH PRESSURE SYSTEM REMAINS CENTERED FAR N/NE OF THE
ISLAND CHAIN WITH AN ASSOCIATED SFC RIDGE SOME 300 MILES N OF
KAUAI...KEEPING A GENERALLY E AND SE WIND REGIME ACROSS THE AREA.
LATEST SOUNDING DATA AND SATELLITE IMAGERY SUGGEST A RATHER STABLE
AIRMASS OVER THE ISLANDS WITH A STRONG TRADE INVERSION AROUND 6
THOUSAND FT AND MOSTLY STABLE STRATOCU STREAMING FROM THE E/SE. THE
WINDS WILL REMAIN MODERATE TONIGHT WITH A FEW BRIEF SHOWERS
POSSIBLE...MAINLY OVER WINDWARD AREAS.

MEANWHILE...A COLD FRONT BOUNDARY CAN BE OBSERVED IN SFC ANALYSIS
DATA AND MODEL SOLUTIONS...LOCATED ABOUT 580 MILES NW OF THE MAIN
HAWAIIAN ISLANDS...AND GRADUALLY MOVING TOWARDS THE AREA. THIS WILL
THEN PUSH THE AFOREMENTIONED SFC RIDGE FURTHER CLOSER TO THE ISLANDS
AND BRING LIGHTER WINDS ON SUN. THIS SYNOPTIC SCENARIO WILL ALLOW
FOR SEA BREEZES TO DEVELOP AND BECOME WIDESPREAD SUN AFTERNOON...BUT
WITH THE RATHER STABLE AIRMASS KEEPING SHOWER ACTIVITY TO A
MINIMUM.

GLOBAL MODELS SHOW FAIR AGREEMENT IN BRINGING THE COLD FRONT
BOUNDARY DOWN THROUGH THE ISLAND CHAIN FROM SUN NIGHT THROUGH LATE
MON...WITH INCREASING WINDS VEERING TO THE WNW BY SUN NIGHT...THEN
BECOMING N AND EVENTUALLY NE BEHIND THE FROPA. MODELS SUGGEST THAT
THE FRONT SHOULD REMAIN FAIRLY SHALLOW...WITH LIMITED MOISTURE AND
INSTABILITY AVAILABLE FOR SHOWER ACTIVITY TO DEVELOP. THUS...EXPECT
PERIODS OF LIGHT TO MODERATE SHOWERS WITH THE FROPA IN
GENERAL...MAINLY OVER THE SMALLER ISLANDS. THE FRONT SHOULD THEN
BEGIN TO QUICKLY BREAK DOWN AS IT MOVES CLOSER TO THE BIG ISLAND
LATE MON. BEST CHANCES OF RAIN WILL RESIDE OVER NE FACING SLOPES MON
NIGHT.

ONCE THE FRONT CLEARS THE ISLANDS...INCREASING N WINDS WILL ADVECT A
COOLER AND DRIER AIRMASS WITH LIMITED SHOWERS EXPECTED FOR THE REST
OF NEXT WEEK...MAINLY OVER WINDWARD AND MOUNTAIN AREAS. THIS IS DUE
TO AN ESTABLISHING STRONG HIGH PRESSURE SYSTEM N OF THE AREA IN THE
WAKE OF THE FRONT. MODELS DEPICT A NOTICEABLE DECREASE IN DEW POINT
VALUES...POSSIBLY DROPPING INTO THE UPPER 50S BY MON NIGHT AND INTO
TUE. THE TRADES WILL FINALLY RE-ESTABLISH BY MID WEEK...WITH
INCREASING LOW LEVEL MOISTURE BRINGING DEW POINTS BACK INTO THE
UPPER 60S AND SHOWERS FOCUSING OVER WINDWARD AND MAUKA AREAS FOR THE
SECOND HALF OF NEXT WEEK.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL OVERNIGHT AND SUNDAY. BRIEF MVFR
CONDITIONS WILL BE POSSIBLE IN PASSING SHOWERS ACROSS WINDWARD
SECTIONS OVERNIGHT. WEAK BACKGROUND FLOW AHEAD OF AN APPROACHING
COLD FRONT ON SUNDAY WILL ALLOW WIDESPREAD SEABREEZES TO DEVELOP
SUNDAY AFTERNOON...WITH ISOLATED SHOWERS AND MVFR CONDITIONS
POSSIBLE ACROSS THE ISLANDS.

&&

.MARINE...
THE COMBINATION OF INCREASING WINDS...SEAS AND THE ARRIVAL OF A
LONG PERIOD SWELL MAY BRING SMALL CRAFT ADVISORY CONDITIONS MONDAY
THROUGH TUESDAY OVER MOST MARINE ZONES...ESPECIALLY THE TYPICALLY
WINDIER WATERS AROUND THE BIG ISLAND AND MAUI COUNTY.

A NEW LONG-PERIOD NNW SWELL WILL CONTINUE TO BUILD THROUGH THE REST
OF TONIGHT AND INTO SUNDAY...WITH PEAK SURF HEIGHTS REMAINING NEAR
BUT BELOW HIGH SURF ADVISORY LEVELS ALONG EXPOSED N AND W SHORES.
THE SWELL WILL BE REINFORCED ON MONDAY...WITH PEAK SURF HEIGHTS
LIKELY REQUIRING AN ADVISORY FOR EXPOSED N AND W SHORES THROUGH
TUESDAY. BREEZY TRADE WINDS LATER IN THE WEEK WILL PRODUCE CHOPPY
SURF ALONG E FACING SHORES THAT IS EXPECTED TO REMAIN BELOW ADVISORY
LEVELS.

&&

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

&&

$$

DISCUSSION/MARINE...REYNES
AVIATION...JACOBSON







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