FXHW60 PHFO 250610
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
800 PM HST THU DEC 24 2009

.SYNOPSIS...
THE BAND OF CLOUDS AND SHOWERS ASSOCIATED WITH A COLD FRONT IS OVER 
OAHU AND KAUAI COUNTIES...AND HEADING EAST TO MAUI COUNTY. THE FRONT 
IS EXPECTED TO STALL ACROSS THESE ISLANDS BRINGING SHOWERY WEATHER 
TO THE WINDWARD AND MOUNTAIN AREAS OF THE SMALLER ISLANDS. A SURFACE 
HIGH FOLLOWING THE FRONT WILL PASS NORTH OF THE ISLANDS FRIDAY AND 
FRIDAY NIGHT...BRINGING A BRIEF PERIOD OF LIGHT TO MODERATE TRADE 
WINDS TO THE ISLANDS. AN APPROACHING SURFACE RIDGE... TRAILING THE 
HIGH...WILL STEER THE CLOUDS AND SHOWERS AWAY. THIS RIDGE WILL 
BRING DRIER WEATHER BUT ALSO LIGHT AND VARIABLE WINDS BY SUNDAY. THE 
RIDGE IS FORECAST TO STAY OVER THE ISLANDS THROUGH AT LEAST TUESDAY.

&&

.DISCUSSION...
THE CLOUD BAND ASSOCIATED WITH A COLD FRONT IS CURRENTLY OVER OAHU 
AND KAUAI COUNTIES. THE BAND IS FORECAST TO ADVANCED MAUI COUNTY 
DURING THE REST OF TONIGHT AND STALL. THE BIG ISLAND IS LIKELY TO 
MISS THE FRONT. THE CLOUDS AND SHOWERS WILL FAVOR THE WINDWARD AND 
MOUNTAIN AREAS OF THE SMALLER ISLANDS. THE REMNANT CLOUDS AND 
SHOWERS WILL LIKELY BE DIRECTED AWAY FROM THE ISLANDS SATURDAY AS 
THE LOW LEVEL WIND FLOW CHANGES FROM THE EAST TO THE SOUTHEAST... 
HENCE MOST OF THE SHOWERS WILL PASS NORTH OF THE ISLANDS. A SHARP 
RIDGE OF HIGH PRESSURE TRAILING THE SURFACE HIGH WILL SETTLE ACROSS 
THE ISLANDS WITH THE SURFACE WINDS TURNING LIGHT AND VARIABLE (L/V) 
BY SUNDAY NIGHT. THE RIDGE WILL BE SUPPORTED BY MID LEVEL RIDGING. 
THUS LOW LEVEL MOISTURE WILL BE CONFINED TO BELOW 8 TO 10 THOUSAND 
FEET.

THE CLOUDS AND SHOWERS ASSOCIATED WITH THIS COLD FRONT ARE LIMITED 
TO NO HIGHER THAN 12000 FEET. THE MID AND UPPER LEVEL SUPPORT FOR 
THIS FRONT IS NIL. IT IS A ZONAL FLOW ALOFT AND THE JET STREAM IS 
NORTH OF 25N. THEREFORE...WE ARE NOT EXPECTING ANYTHING 
EXTRAORDINARY SUCH AS THE LAST FRONT THIS PAST WEEKEND.

THERE IS A GOOD CHANCE THE VOG FROM THE BIG ISLAND WILL REACH THE 
SMALLER ISLANDS SUNDAY...AND LINGER THROUGH THE FIRST HALF OF THE 
WORK WEEK. THE LOWER BOUNDARY WINDS ARE EXPECTED TO BE SOUTHERLY 
THAT WILL CARRY THE VOG TO THE SMALLER ISLANDS. THE SHARP RIDGE... 
ACCOMPANIED BY L/V WINDS...WILL LIKELY KEEP THE VOG AT BAY OVER THE 
ISLANDS.

&&

.MARINE...
SURF REPORTS FROM THE KONA COAST THIS AFTERNOON PROMPTED A HIGH SURF 
WARNING. WAVE WATCH DATA ALSO SUPPORTED WARNING LEVEL SURF FOR MOST 
OF THE KONA...LEEWARD BIG ISLAND COAST. 

THE LATEST SWELL DATA FROM BUOY 51101 HAS THE SWELL CONTINUING TO 
CLIMB. IT IS AT 19 FEET AND PRIMARY PERIOD OF 16 SECONDS THIS PAST 
HOUR. MATCHING UP WITH WAVE WATCH...IT IS A COUPLE OF FEET SMALLER 
AND THE PERIOD A FEW SECONDS SHORTER. BUT THE SWELL HAS LONGER 
PERIOD ENERGY TO 24 SECONDS. SO NEVER THE LESS IT IS BIG AND IN THE 
WARNING RANGE. 

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF WARNING UNTIL 6 PM HST SATURDAY FOR KONA-KOHALA 
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 PM HST SATURDAY 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.

&&

$$

H LAU