FXHW60 PHFO 030630
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST WED DEC 2 2009

.SYNOPSIS...
LIGHT WINDS AND CLEAR SKIES WILL PERSIST TONIGHT. A COLD FRONT 
APPROACHING FROM THE NORTHWEST WILL ARRIVE TOMORROW 
NIGHT...PRODUCING INCREASED SHOWERS AND POSSIBLE 
THUNDERSTORMS...ALONG WITH SLIGHTLY STRONGER SOUTHWESTERLY WINDS. 
WINDS WILL WEAKEN AGAIN THIS WEEKEND AND INTO NEXT WEEK...WITH 
SHOWERS EXPECTED IN INTERIOR SECTIONS DURING THE AFTERNOON...AND 
CLEAR NIGHTS.  

&&

.DISCUSSION...
A WEAK PRESSURE GRADIENT PERSISTS OVER THE STATE WHICH IS PRODUCING 
LIGHT WINDS...WHICH WILL LEAD TO LAND BREEZES TONIGHT WITH CLEAR 
SKIES. THESE CALM WINDS WILL PERSIST UNTIL TOMORROW AFTERNOON WHEN A 
COLD FRONT APPROACHES THE ISLANDS FROM THE NORTHWEST...RESULTING IN 
WINDS BECOMING SOUTHWESTERLY AS THE FRONT DRAWS UP MOISTURE FROM THE 
ITCZ. THIS FRONT WILL MOVE THROUGH THE ISLANDS LATE THURSDAY AND 
FRIDAY. A BROAD UPPER LEVEL TROUGH IS EXPECTED TO BRING SOME COLDER 
500MB TEMPERATURES DURING THIS TIME...AND THE MODEL SOUNDINGS SHOW 
THE LOW LEVEL INVERSION BEING ERODED IN ADDITION TO THE 
AFOREMENTIONED ADVECTION OF MOISTURE. AS A RESULT...HEAVY SHOWERS 
AND THUNDERSTORMS ARE POSSIBLE WITH THIS FRONTAL PASSAGE TOMORROW 
NIGHT AND FRIDAY.

AFTER THE PASSAGE OF THE FRONT...GFS SHOWS SUBTROPICAL RIDGING 
PERSISTING OVER THE STATE PRODUCING LIGHT WINDS ONCE AGAIN...ALONG 
WITH INCREASED STABILITY AS SUBSIDENCE AND WARMING LAPSE RATES ARE 
EXPECTED AS UPPER LEVEL RIDGING ENTERS REGION. THIS SETUP FAVORS A 
SEA BREEZE-LAND BREEZE WEATHER PATTERN FOR THIS WEEKEND...WITH 
CLOUDY SKIES AND SEA BREEZE SHOWERS DURING THE AFTERNOONS...AND 
CLEAR NIGHTS. EARLY NEXT WEEK...ANOTHER FRONT APPROACHES THE 
ISLANDS. HOWEVER...AT THIS TIME IT APPEARS THAT THE FRONT WILL 
WEAKEN AND STALL ONCE IT REACHES KAUAI.  

A VERY LARGE NORTHWEST SWELL IS EXPECTED TO ARRIVE ON SATURDAY WITH 
AN EVEN LARGER ONE ON MONDAY...WITH BOTH EVENTS EXPECTED TO PRODUCE 
WARNING LEVEL SURF. SEE MARINE SECTION AND SURF PRODUCTS FOR MORE 
DETAILS. 

&&

.MARINE...
FRESH NORTHWEST SWELL WILL BUILD QUICKLY INTO THURSDAY LIKELY 
TOPPING OUT UP TO 20 FEET AT TIMES THURSDAY...THEN DROP BELOW 
ADVISORY LEVELS AGAIN BY FRIDAY. 

THE GFS AND ECMWF SOLUTIONS REMAIN IN VERY GOOD AGREEMENT DEVELOPING 
A POWERFUL 945-950MB HURRICANE FORCE LOW WITH AN IMPRESSIVE FETCH 
AIMED AT HAWAII OVER THE WEEKEND. AS OF NOW...FORERUNNERS COULD 
ARRIVE AS EARLY AS LATE SUNDAY AFTERNOON. ALTHOUGH THIS SYSTEM HAS 
NOT FORMED YET...PRELIMINARY NWW3 NUMBERS REMAIN IMPRESSIVE FROM 
RECENT RUNS. EXTRA LARGE SURF IS EXPECTED EARLY NEXT WEEK. 

&&

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

SMALL CRAFT ADVISORY TILL 8 PM HST THURSDAY 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.

&&

$$

HARRISON/BIRCHARD