FXHW60 PHFO 241353
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
350 AM HST THU DEC 24 2009
.SYNOPSIS...
A WEAK COLD FRONT WILL AFFECT THE STATE THIS AFTERNOON THROUGH
CHRISTMAS DAY...BRINGING SOME SHOWERS TO MAINLY WINDWARD LOCATIONS.
THE FRONT WILL DISSIPATE OVER THE ISLANDS BY SATURDAY...BUT HIGH
PRESSURE MOVING NORTH OF THE STATE WILL USHER IN A PERIOD OF LIGHT
TO MODERATE TRADES INTO EARLY NEXT WEEK. LEFTOVER MOISTURE IN THE
AREA FROM THE DISSIPATED FRONT WILL CONTINUE TO BRING THE THREAT FOR
PASSING WINDWARD AND MAUKA SHOWERS.
&&
.DISCUSSION...
A WEAK RIDGE OVER THE STATE EARLY THIS MORNING IS RESULTING IN
MAINLY CLEAR SKIES AND LIGHT WINDS. TEMPERATURES HAVE COOLED INTO
THE LOWER TO MID 60S IN MOST LOCATIONS WITH THE NORMALLY COLDER
AREAS DOWN INTO THE 50S. NO MEASURABLE RAINFALL OCCURRED OVERNIGHT
STATEWIDE.
A COLD FRONT IS POSITIONED ABOUT 80 MILES NORTHWEST OF KAUAI AND
MOVING EAST SOUTHEAST AT ABOUT 20 MPH. THE CLOUD BAND ASSOCIATED
WITH THE FRONT IS LOW TOPPED STRATOCUMULUS...INDICATIVE OF THE
STABLE ENVIRONMENT ALOFT. THIS WEAK COLD FRONT WILL MOVE ACROSS
KAUAI EARLY THIS AFTERNOON AND REACH OAHU BY LATE THIS AFTERNOON AND
EVENING. THE FRONT WILL BE DISSIPATING AS IT REACHES MAUI COUNTY
OVERNIGHT AND CHRISTMAS DAY. AS THERE IS LITTLE IN THE WAY OF UPPER
LEVEL SUPPORT WITH THIS FRONT...EXPECTING MOST OF THE SHOWERS TO
REMAIN CONFINED TO WINDWARD AND MAUKA LOCATIONS. NORTHEASTERLY
TRADES WILL INCREASE TO MODERATE LEVELS BEHIND THE FRONT AND REMAIN
OVER THE STATE ON CHRISTMAS DAY AS A 1020 MB HIGH MOVES IN NORTH OF
THE STATE. LIGHT TO MODERATE EAST TO SOUTHEASTERLY TRADES ARE
EXPECTED OVER THE WEEKEND AS THE HIGH MOVES TO THE NORTHEAST OF THE
STATE. AS THE TRADES BECOME MORE EAST AND SOUTHEASTERLY...REMNANT
MOISTURE FROM THE FRONTAL BOUNDARY WILL BRING A BETTER CHANCE OF
SHOWERS TO WINDWARD AREAS ON SATURDAY AND SUNDAY.
THE GFS AND EC MODELS SHOW LIGHT EAST TO SOUTHEAST FLOW OVER THE
ISLANDS THROUGH MUCH OF NEXT WEEK AS A WEAK RIDGE REMAINS TO OUR
NORTHEAST.
&&
.MARINE...
THE CURRENT NORTHWEST SWELL IS STILL BRINGING HIGH SURF ADVISORY
LEVEL SURF HEIGHTS TO NORTH AND WEST FACING SHORES. THESE CONDITIONS
WILL CONTINUE THIS MORNING AHEAD OF A MUCH LARGER INCOMING NORTHWEST
SWELL.
THIS NEXT VERY LARGE NORTHWEST SWELL WILL AFFECT THE NORTH AND WEST
FACING SHORES INTO THE UPCOMING HOLIDAY WEEKEND. THE WAVEWATCH MODEL
PREDICTS OPEN OCEAN SWELL HEIGHTS OF AROUND 20 FEET WITH PERIODS IN
THE 16 TO 18 SECOND RANGE. STILL AWAITING INDICATIONS OF THE NEW
LONG PERIOD ENERGY AT BUOY 51001...WHERE THE SWELL SHOULD SHOW UP
IN THE NEXT HOUR OR TWO ACCORDING TO WAVEWATCH III. USING THE LATEST
MODEL TIMING...THE SURF WILL BUILD RAPIDLY MIDDAY TODAY ALONG NORTH
AND WEST FACING SHORES OF NIIHAU AND KAUAI WITH WARNING LEVEL SURF
EXPECTED THERE DURING THE AFTERNOON HOURS. THIS SWELL WILL THEN
MOVE DOWN THE ISLAND CHAIN LATER THIS AFTERNOON THROUGH CHRISTMAS
DAY. HAVE ADJUSTED THE HIGH SURF WARNING TO BEGIN AT NOON TODAY TO
ACCOUNT FOR THE EXPECTED ONSET OF CONDITIONS AT KAUAI.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL NOON HST TODAY FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-MAUI CENTRAL VALLEY-WINDWARD
HALEAKALA.
HIGH SURF WARNING FROM NOON TODAY UNTIL 6 PM HST SATURDAY FOR
NIIHAU-KAUAI WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH
SHORE-OAHU KOOLAU-MOLOKAI-MAUI WINDWARD WEST-MAUI CENTRAL VALLEY-
WINDWARD HALEAKALA.
SMALL CRAFT ADVISORY UNTIL 6 AM HST FRIDAY FOR KAUAI NORTHWEST
WATERS-KAUAI WINDWARD WATERS-KAUAI LEEWARD WATERS-KAUAI CHANNEL-
OAHU WINDWARD WATERS-OAHU LEEWARD WATERS-KAIWI CHANNEL-MAUI
COUNTY WINDWARD WATERS-MAUI COUNTY LEEWARD WATERS-ALENUIHAHA
CHANNEL-BIG ISLAND WINDWARD WATERS-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.
&&
$$
BRENCHLEY
