FXHW60 PHFO 121330

AFDHFO



AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE HONOLULU HI

400 AM HST FRI MAR 12 2010



.SYNOPSIS...

HIGH PRESSURE TO THE NORTH OF THE ISLANDS WILL CONTINUE TO BRING 

BREEZY TRADES THROUGH THIS AFTERNOON. THE TRADES WILL BRING 

PASSING WINDWARD AND MAUKA SHOWERS THAT WILL BE MORE ACTIVE DURING 

NIGHTS AND MORNINGS...WITH SOME SHOWERS BEING BLOWN TO LEEWARD 

AREAS. TRADES WILL WEAKEN A BIT THIS EVENING AND THEN STRENGTHEN 

AGAIN SUNDAY THROUGH MONDAY. A FRONT WILL BRING SOME INCREASED 

SHOWERS OVER THE STATE LATE SUNDAY AND EARLY MONDAY. WINDS WILL 

BECOME LIGHT AND VARIABLE TUESDAY AND WEDNESDAY. 



&&



.DISCUSSION...

HIGH PRESSURE NORTH OF THE STATE IS CURRENTLY BRINGING BREEZY TRADES 

TO THE STATE. RIDGING WILL BE FORCED SOUTHWARD TO ONLY ABOUT 300 

MILES NORTH OF THE ISLANDS BY THIS EVENING...LOWERING WINDS TO 

MODERATE STRENGTH. THERE ARE INDICATIONS THAT WINDS ARE ALREADY 

STARTING TO WEAKEN...WITH SURFACE PRESSURE DECREASING AND OVERALL 

WIND SPEEDS ON THE DOWNWARD TREND. MODELS SEEM TO SUGGEST THAT THE 

FRONT WILL BE TOO WEAK TO MAKE IT THROUGH THE ISLAND CHAIN...WITH 

THE FEATURE STALLING AS IT REACHES KAUAI. MODELS ALSO INDICATE THAT 

PRE-FRONTAL MOISTURE WILL BE BROUGHT UP OVER THE ISLANDS SUNDAY AND 

MONDAY. WITH TRADE WINDS CONTINUING...SHOWERS WILL AFFECT MAINLY 

WINDWARD AND MOUNTAIN SLOPES.



THERE HAS BEEN LESS SHOWER ACTIVITY OVERNIGHT COMPARED TO WEDNESDAY 

NIGHT...WITH RAIN GAGE REPORTS SHOWING SPARSE AND LIGHT RAINFALL 

ACCUMULATIONS. UPPER LEVEL RIDGING IS CAUSING INCREASED SUBSIDENCE 

OVER THE ISLANDS. THE ATMOSPHERE HAS BECOME MORE STABLE AS A 

RESULT...WITH THE 12Z SOUNDINGS FROM LIHUE AND HILO SHOWING LOW 

LEVEL INVERSIONS CONTINUING TO DECREASE IN HEIGHT...AT ABOUT 6400 

AND 7500 FT RESPECTIVELY. WITH THE LOWER INVERSION HEIGHTS LIMITING 

THE VERTICAL DEVELOPMENT OF CLOUDS...THE CHANCES OF HEAVY RAIN 

OCCURRING FROM SHOWERS IS LOW. PRECIPITABLE WATER VALUES ARE ALSO 

LOW...AT AROUND 1 INCH. THE OVERALL TREND IS FOR INCREASED STABILITY 

FOR THE NEXT COUPLE DAYS UNTIL THE FRONT MENTIONED EARLIER GETS 

CLOSE TO THE STATE LATE SUNDAY. ALTHOUGH RAINFALL ACCUMULATIONS WILL 

BE LIGHT...THERE IS ENOUGH MOISTURE FOR TRADE SHOWERS TO REMAIN 

PRESENT...BECOMING MORE ACTIVE DURING THE NIGHT AND MORNING HOURS.



HIGH PRESSURE WILL MOVE IN BEHIND THE FRONT MONDAY...WHICH WILL 

CAUSE TRADE WINDS TO STRENGTHEN...BECOMING BREEZY. RIDGING WILL MOVE 

OVER THE STATE TUESDAY AFTERNOON...WEAKENING THE WINDS TO LIGHT AND 

VARIABLE. MODELS SHOW ANOTHER FRONT APPROACHING THE ISLANDS TUESDAY 

AFTERNOON. 



&&



.MARINE...

A SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH THIS AFTERNOON FOR 

ALL HAWAIIAN COASTAL WATERS. WINDS WILL BE AT THE 25 KT ADVISORY 

THRESHOLD IN THE TYPICALLY WINDY AREAS AROUND MAUI AND THE BIG 

ISLAND...WHILE SEAS ARE AT THE 10 FOOT THRESHOLD OVER THE REMAINING 

AREAS.



A NEW NORTHWEST SWELL WILL ARRIVE SUNDAY NIGHT BRINGING NEAR 

WARNING LEVEL SURF TO THE STATE. THE SWELL WILL START TO SLOWLY 

LOWER MONDAY NIGHT.



&&



.HFO WATCHES/WARNINGS/ADVISORIES...

SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR ALL HAWAIIAN 

WATERS.



&&



$$



HARRISON/BIRCHARD





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