FXHW60 PHFO 041031 AAA
AFDHFO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HONOLULU HI
1230 AM HST FRI DEC 4 2009

.UPDATE...
WINDS OVER THE BIG ISLAND SUMMITS HAVE INCREASED TO 40 TO 50 
MPH...SO THE WIND ADVISORY FOR THE BIG ISLAND SUMMITS HAS BEEN 
UPGRADED TO A HIGH WIND WARNING EFFECTIVE UNTIL 6 AM THIS MORNING. 

&&

.SYNOPSIS...
THUNDERSTORMS AND HEAVY SHOWERS RESULTING FROM A COLD FRONT WILL 
MOVE OVER THE ISLANDS LATE THURSDAY NIGHT AND FRIDAY MORNING. A 
SECOND WEAKER FRONT WILL REACH KAUAI ON MONDAY AND THEN DISSIPATE 
OVER THE ISLAND. TRADES WILL RETURN ON TUESDAY AS HIGH PRESSURE 
MOVES IN NORTH OF THE STATE. 

&&

.DISCUSSION...
A COLD FRONT FROM THE NORTHWEST IS CURRENTLY MOVING TOWARD THE 
ISLANDS...WITH PRE-FRONTAL HEAVY SHOWERS AND THUNDERSTORMS BEING 
DRAWN UP OVER OAHU AND MOLOKAI. AS THE NIGHT GOES ON...THIS 
PRE-FRONTAL PRECIPITATION WILL MOVE OVER MAUI AND THE BIG ISLAND. 
GFS SHOWS THIS PRE-FRONTAL ACTIVITY BEING STRONGER THAN THE ACTUAL 
FRONT. THE FRONT SHOULD ARRIVE ON KAUAI BY EARLY FRIDAY 
MORNING...MOVE THROUGH THE OTHER ISLANDS...AND GET TO THE BIG ISLAND 
BY EARLY AFTERNOON ON FRIDAY. COLD 500MB TEMPERATURES ASSOCIATED 
WITH BROAD UPPER LEVEL TROUGHING IS CREATING AN UNSTABLE 
ATMOSPHERE...WHICH IS HELPING TO SUPPORT SHOWER AND THUNDERSTORM 
ACTIVITY. SOUTHWESTERLY WINDS WILL INCREASE AHEAD OF THE FRONT AND 
THEN TURN NORTHEAST AFTER THE FRONT MOVES THROUGH. STRONG GUSTS ARE 
POSSIBLE WITH THE PASSAGE OF THE FRONT...POSSIBLY REACHING 45 MPH. 

AFTER THE FRONT MOVES OUT...SUBTROPICAL RIDGING WILL BE OVER THE 
ISLANDS WHICH WILL RESULT IN LIGHT WINDS UNTIL MONDAY WHEN A NEW 
FRONT APPROACHES. THIS FRONT WILL BE WEAKER THAN THE CURRENT PENDING
FRONT...AND IS EXPECTED TO REACH KAUAI AND THEN QUICKLY DISSIPATE. 
BY THIS TIME...UPPER LEVEL RIDGING WILL BE IN PLACE WHICH WILL WARM 
THE 500MB TEMPERATURES AND INCREASE SUBSIDENCE...RESULTING IN A 
STABLE ATMOSPHERE. THUS...ANY SHOWERS THAT DO OCCUR FROM THIS FRONT 
ARE NOT EXPECTED TO BE HEAVY. NEVERTHELESS...INCREASED SHOWER 
ACTIVITY WILL BE POSSIBLE ON KAUAI FOR MONDAY AFTERNOON. 
THEN...RIDGING WILL MOVE IN FROM THE WEST AND BE IN PLACE NORTH OF 
THE STATE...RESULTING IN A RETURN OF TRADE WINDS THROUGH FRIDAY. 

&&

.MARINE...
THE NORTHWEST SWELL IS CONTINUING TO LOWER...BUT ADVISORY LEVEL SURF 
IS EXPECTED TO CONTINUE UNTIL EARLY FRIDAY MORNING. THIS CURRENT 
NORTHWEST SWELL IS THE FIRST OF 3 SIGNIFICANT NORTHWEST SWELLS. THE 
NEXT NORTHWEST SWELL IS ON TAP FOR SATURDAY WITH AN EVEN LARGER ONE 
SLATED FOR MONDAY. BOTH OF THESE SWELLS ARE EXPECTED TO REACH 
WARNING LEVEL SURF. SEE SURF PRODUCTS FOR MORE DETAILS.

ALSO A SMALL CRAFT ADVISORY HAS BEEN EXTENDED TO 6 AM FRIDAY... 
EITHER DUE TO WIND...10 FT SEAS OR BOTH. 

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 AM HST FRIDAY FOR THE NORTH AND WEST 
FACING SHORES OF NIIHAU...KAUAI...OAHU...MOLOKAI...AND NORTH FACING 
SHORES OF MAUI.

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 
AND BIG ISLAND WINDWARD WATERS.

HIGH WIND WARNING UNTIL 6 AM HST FRIDAY FOR THE BIG ISLAND SUMMITS.

WIND ADVISORY UNTIL 6 AM HST FRIDAY FOR HALEAKALA SUMMIT. 

&&

$$

HARRISON/HUI