FXUS66 KEKA 251155
 AFDEKA
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE EUREKA CA
 355 AM PST WED NOV 25 2009
 
 .SYNOPSIS...HIGH PRESSURE WILL REMAIN OVER THE REGION FOR ANOTHER 
 DAY...WITH ABOVE NORMAL TEMPERATURES. A COLD FRONT WILL CROSS 
 THE REGION LATE THANKSGIVING DAY...BRINGING THE THREAT FOR RAIN 
 THROUGH EARLY FRIDAY. ANOTHER WEAK SYSTEM MAY BRING A FEW LIGHT 
 SHOWERS TO THE REGION SATURDAY. THEREAFTER HIGH PRESSURE WILL BRING 
 DRY AND WARMER WEATHER.
 
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 .DISCUSSION...THE MAIN FORECAST ISSUE CONTINUES TO BE THE SYSTEM 
 SLATED FOR LATE THANKSGIVING DAY INTO EARLY FRIDAY.
 
 A LOW LEVEL TEMPERATURE INVERSION HAS BECOME MORE PRONOUNCED 
 COMPARED TO PREVIOUS DAYS. AT 2 AM...IT WAS 40 DEG F HERE AT THE 
 OFFICE ON WOODLEY ISLAND WHILE JUST UP THE HILL AT KNEELAND THE 
 MERCURY STOOD AT 62...SO IT SHOULD BE LITTLE SURPRISE THAT MARINE 
 STRATUS CONTINUES TO DEVELOP UNDER THIS REGIME. MODERATE OFFSHORE 
 FLOW WAS KEEPING THE BULK OF STRATUS OFFSHORE AND IT SHOULD STAY 
 THERE THROUGH MUCH OF THE DAY...WHILE WE WORK ON GETTING RID OF THE 
 OVERCAST THAT SNEAKED IN AROUND HUMBOLDT BAY. OTHERWISE ANOTHER 
 PLEASANT DAY IS EXPECTED WITH TEMPERATURES...PARTICULARLY AT HIGHER 
 ELEVATIONS AND IN THE UKIAH AREA...AVERAGING ABOVE SEASONAL NORMS.
 
 CHANGES ARE EXPECTED TO BEGIN OVERNIGHT AS A SURFACE LOW OFFSHORE 
 DEEPENS AND MAKES A BEELINE FOR THE OR/WA COAST. WITH THE ASSOCIATED 
 WARM FRONT WELL TO THE NORTH OF THE AREA...IT WOULD APPEAR THE 
 THREAT FOR MEASURABLE RAIN WILL HOLD OFF UNTIL THE AFTERNOON ON 
 THANKSGIVING DAY...AND EVEN THEN IT WILL PROBABLY BE CONFINED TO THE 
 COAST NORTH OF CAPE MENDOCINO. COLD FRONTAL PASSAGE IS EXPECTED 
 THURSDAY NIGHT AND MOST AREAS SHOULD RECEIVE SOME RAIN...ALTHOUGH 
 AMOUNTS IN SOUTHERN MENDOCINO AND EASTERN TRINITY COUNTIES WILL 
 PROBABLY BE NO HIGHER THAN A TENTH OF AN INCH. IN CONTRAST...THREE 
 QUARTERS OF AN INCH OR EVEN A LITTLE MORE IS POSSIBLE IN DEL NORTE 
 COUNTY. ACCUMULATING SNOWS WILL REMAIN ABOVE PASS LEVEL...BUT IT IS 
 POSSIBLE THAT SOME SNOW MAY MIX IN WITH THE RAIN DOWN TO 2500 OR 
 3000 FEET ON FRIDAY WITH HEAVIER SHOWERS. ONE CHANGE FOR THE 
 SATURDAY FORECAST TO REFLECT NEWER MODEL TRENDS IS TO HIT THE CLOUD 
 COVER A BIT HARDER ACROSS NORTHERN ZONES IN ASSOCIATION WITH A 
 PASSING FRONT. WHILE MOST RAIN SHOULD STAY IN OREGON...SOME VERY 
 LIGHT RAIN CAN NOT BE ENTIRELY RULED OUT NORTH OF CAPE MENDOCINO. 
 WE`RE STILL EXPECTING A MILD AND DRY PERIOD FOR THE TAIL END OF THE 
 WEEKEND INTO EARLY NEXT WEEK WITH HIGH PRESSURE SETTING UP ACROSS 
 THE REGION. BURGER    
 
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 .AVIATION...SATELLITE IMAGERY SHOWS AREAS OF STRATUS HOVERING AROUND 
 HUMBOLDT BAY AND JUST OFFSHORE OF NORTHWEST CALIFORNIA. A WEAK 
 PRESSURE GRADIENT AND THE ASSOCIATED CALM WINDS ARE THREATENING TO 
 ALLOW THE STRATUS TO MOVE/FORM OVER CEC AND ACV THIS MORNING. BEST 
 GUESS IS THE STRATUS WILL REMAIN AWAY FROM THESE SITES, BUT SOME 
 TEMPORARY REDUCTIONS IN VISIBILITY ARE POSSIBLE DUE TO MIST/SHALLOW 
 FOG. ANY STRATUS/FOG THAT DOES FORM THIS MORNING SHOULD BURN OFF 
 SHORTLY AFTER SUNRISE, THOUGH SOME MVFR IS EXPECTED ALONG THE COAST 
 DUE TO MIST. INLAND SITES WILL REMAIN VFR. STROZ
 
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 .MARINE...WEAK HIGH PRESSURE WILL MAINTAIN LIGHT WINDS THROUGH 
 TONIGHT. A NORTHWEST SWELL JUST UNDER 10 FT NEAR 13 SECONDS WILL 
 ALSO CONTINUE TODAY...THOUGH IT WILL BECOME MIXED WITH A LONGER 
 PERIOD NORTHWEST SWELL NEAR 18 SECONDS TONIGHT. THIS IS CONFIRMED BY 
 BUOY 6, 600 NM WEST OF EUREKA, WHICH STARTED PICKING UP THE LONG 
 PERIOD SWELL AROUND 09Z. SWELL DECAY HAS THIS ARRIVING NEAR 06Z 
 THURSDAY. THIS WILL BECOME THE PRIMARY SWELL ON THURSDAY AND BUILD 
 TO NEAR 15 FT. THEREFORE, HAVE ISSUED A SCA FOR HAZARDOUS SEAS FOR 
 ALL THE WATERS BEGINNING LATER TONIGHT. MODELS ARE STILL IN GOOD 
 AGREEMENT SHOWING A FRONT MOVING ACROSS THE WATERS LATE THURSDAY 
 INTO EARLY FRIDAY. SOUTHERLY WINDS WILL INCREASE AHEAD OF THE FRONT, 
 THOUGH MODELS CONTINUE TO INDICATE THAT THERE WILL NOT BE WIDESPREAD 
 GALE FORCE GUSTS. SO NO GALE WARNINGS ARE UP, HOWEVER THERE MAY BE 
 OCCASIONAL GALE FORCE GUSTS AS THE FRONT MOVES THROUGH AND THE WINDS 
 VEER TO THE NORTHWEST BEHIND THE FRONT. SEAS WILL ALSO BECOME 
 HAZARDOUS WITH THE MAIN IMPACTS BEING WIND WAVES PRE FRONT AND A 
 LARGE NORTHWEST SWELL POST FRONT. THE ENP AND SWAN MODEL SHOW A 
 NORTHWEST SWELL NEAR 20 FT BUILDING IN EARLY FRIDAY MORNING. HAVE 
 HELD OFF ON ISSUING ANY HAZARDOUS SEAS WATCHES BECAUSE IT`S STILL 
 BORDERING FOUR TO FIVE PERIODS OUT AND THE START TIME IS NOT 
 CERTAIN. THE SWELL MAY ALSO WARRANT A HIGH SURF ADVISORY, BUT ONCE 
 AGAIN IT`S STILL TOO EARLY TO ISSUE DUE TO UNCERTAINTY. THE DAY CREW 
 WILL NEED TO TAKE ANOTHER LOOK AT THIS. THE SWELL WILL START TO 
 SUBSIDE LATE FRIDAY, BUT SEAS WILL GENERALLY REMAIN ABOVE 10 FT 
 THROUGH THE WEEKEND. STROZ     
 
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 .EKA WATCHES/WARNINGS/ADVISORIES...
 
 SMALL CRAFT ADVISORY ALL WATERS.
 
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