FXHW60 PHFO 231343
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
330 AM HST WED DEC 23 2009
.SYNOPSIS...
A SERIES OF WEAK COLD FRONTS WILL AFFECT THE ISLANDS OVER THE NEXT
SEVERAL DAYS. BRIEF BOUTS OF LIGHT TO MODERATE TRADES WILL FOLLOW
EACH FRONT...WITH ANY FRONTAL SHOWERS PREDOMINANTLY FOCUSING OVER
WINDWARD AND MAUKA AREAS.
&&
.DISCUSSION...
THE SURFACE RIDGE AXIS IS POSITIONED JUST NORTH OF THE STATE THIS
MORNING...ABOUT 100 MILES OR LESS NORTH OF KAUAI...AND THIS HAS
RESULTED IN DECREASING TRADE WINDS AND THE DOMINANCE OF LAND BREEZES
WITH MOSTLY CLEAR SKIES. ONLY A LIGHT SHOWER OR TWO HAS BEEN SEEN ON
WINDWARD LOCATIONS IN PAST HOUR AND THESE WILL CONTINUE TO DECREASE
AS THE RIDGE SLIDES SOUTH OVER THE ISLANDS TODAY AND TONIGHT.
AFTERNOON SEA BREEZES WILL DEVELOP TODAY AND THURSDAY AND WILL BRING
FLAT CUMULUS BUILDUPS OVER THE INTERIORS...HOWEVER THE DRY AND
STABLE AIRMASS WILL PRECLUDE MUCH IN THE WAY OF SIGNIFICANT SHOWER
DEVELOPMENT.
A COLD FRONT WELL NORTHWEST OF THE STATE THIS MORNING IS EXPECTED
TO REACH KAUAI LATE THURSDAY AFTERNOON AND TO REACH OAHU THURSDAY
NIGHT. THE FRONT WILL BRING AN INCREASING CHANCE OF SHOWERS...BUT
AS THE SURFACE FRONTAL BOUNDARY LACKS SUPPORT ALOFT...ONLY LIGHT
RAINFALL ACCUMULATIONS ARE ANTICIPATED. THE FRONT WILL BECOME SO
WEAK AS IT PASSES OAHU THAT IT BREAKS UP AND DISSIPATES COMPLETELY
BEFORE CROSSING MAUI COUNTY ON CHRISTMAS DAY. QUIET WEATHER IS
EXPECTED FOR CHRISTMAS THROUGH THE COMING WEEKEND AS LIGHT TO
MODERATE TRADES DOMINATE WITH WEAK RIDGING TO THE NORTH. ANOTHER
WEAK COLD FRONT MAY POSSIBLY BRING UNSETTLED WEATHER TO KAUAI AND
OAHU AROUND THE MIDDLE OF NEXT WEEK...WITH DETAILS REMAINING
UNCERTAIN THAT FAR OUT...AS THE VARIOUS MODELS DISAGREE TO EXTENT
TO WHICH THIS FRONT WILL HOLD TOGETHER AS IT APPROACHES THE
STATE.
&&
.MARINE...
BUOY DATA SUGGESTS THE CURRENT NORTHWEST SWELL HAS PEAKED AT KAUAI
AND OAHU AROUND 11 OR 12 FEET AT 15 SECONDS...TRANSLATING TO NORTH
SHORE SURF HEIGHTS OF 22 TO 24 FEET...EARLY THIS MORNING AND WILL
GRADUALLY DROP TODAY THROUGH THURSDAY. SURF HEIGHTS FOR NORTH AND
WEST SHORES OF NIIHAU...KAUAI...OAHU AND MOLOKAI AND NORTH FACING
SHORES OF MAUI WILL REMAIN SOLIDLY AT HIGH SURF ADVISORY LEVELS FOR
TODAY THROUGH AT LEAST TONIGHT...AND WILL CANCEL THE HIGH SURF
WARNING AND REPLACE WITH HIGH SURF ADVISORY THROUGH TONIGHT.
THE NEXT NORTHWEST SWELL DUE IN LATE THURSDAY THROUGH CHRISTMAS DAY
IS STILL EXPECTED TO BE MUCH LARGER AND WELL ABOVE THE WARNING
THRESHOLDS OF 25 FEET FOR NORTH FACING SHORES AND 20 FEET ON WEST
FACING SHORES.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 AM HST THURSDAY FOR NORTH AND WEST FACING
SHORES OF NIIHAU...KAUAI...OAHU AND MOLOKAI...AS WELL AS FOR NORTH
FACING SHORES OF MAUI.
&&
$$
BRENCHLEY
