Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 222247
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
247 PM PST SAT NOV 22 2014

.SYNOPSIS...POST FRONTAL SHOWERS WILL DIMINISH TONIGHT AS HIGH
PRESSURE STARTS TO BUILD INTO THE AREA. A WEAK WARM FRONT MAY
BRING SOME LIGHT RAIN MONDAY BEFORE DRY WEATHER RETURNS THROUGH
THANKSGIVING. LATE IN THE WEEK ADDITIONAL RAIN IS POSSIBLE.


&&

.DISCUSSION....SHORT TERM...(THROUGH MONDAY NIGHT) THE COLD FRONT
IS NOW SOUTH OF THE AREA LEAVING NORTHWEST FLOW OVER NORTHWEST
CALIFORNIA. THIS HAS ALLOWED MUCH DRIER AIR TO MOVE OVER THE
REGION. HOWEVER WITH UPSLOPING WINDS SHOWERS HAVE CONTINUE TO
DEVELOP OVER THE INTERIOR. AS DRIER AIR CONTINUES TO FILTER IN AND
UPPER LEVEL RIDGING BUILDS OVER THE WEST COAST...SHOWERS SHOULD
COME TO AN END OVERNIGHT INTO SUNDAY MORNING. HIGH CLOUDS WILL
STREAM OUT AHEAD OF AN APPROACHING WARM FRONT RESTRICTING FULL
CLEARING ON SUNDAY. THIS FRONT MAY BRING SOME VERY LIGHT RAIN OR
SPRINKLES TO AREAS NORTH OF CAPE MENDOCINO ON MONDAY INTO MONDAY
EVENING BUT CONFIDENCE IN ANY RAINFALL IS PARTICULARLY LOW. THE
CURRENT MODEL SOLUTIONS SUPPORT THE FRONT SHIFTING NORTH JUST OFF
THE WEST COAST LEAVING NORTHWEST CALIFORNIA DRY. HOWEVER A SHIFT
OF ONLY 20-50 MILES EAST COULD RESULT IN A WETTER MONDAY THAN
FORECAST.

VALLEY FOG WILL BE A CONCERN EACH NIGHT AND MORNING AS MOISTURE
POOLS ONTO THE VALLEY FLOORS. SOME AREAS MAY SEE FREEZING
TEMPERATURES IN TRINITY COUNTY WHICH COULD RESULT IN SLICK ROADWAYS
AND RIME ON SURFACES WHERE FOG DEVELOPS. TEMPERATURES MAY FALL
INTO THE MID 30S IN THE VALLEYS OF INTERIOR HUMBOLDT AND DEL NORTE
AS WELL...BUT DUE TO THE FOG...FROST IS NOT ANTICIPATED TO BE
WIDESPREAD AND NO FROST ADVISORY WILL BE ISSUED AT THIS TIME. RPA


.LONG TERM...(TUESDAY THROUGH SATURDAY) UPPER LEVEL RIDGING OVER THE
WEST COAST WILL RESULT IN DRY CONDITIONS TUESDAY INTO WEDNESDAY.
TEMPERATURES WILL ALSO WARM SEVERAL DEGREES ABOVE NORMAL. RAIN
CHANCES WILL RETURN THURSDAY INTO FRIDAY AS THE RIDGE BEGINS TO
BREAK DOWN AND A STORM SYSTEM BEGINS TO APPROACH THE COAST. THE 12Z
RUNS OF THE GFS AND ECMWF ARE IN REMARKABLE AGREEMENT THROUGHOUT THE
FORECAST PERIOD...WITH RAIN SPREADING OVER THE AREA ON FRIDAY AND
CONTINUING THROUGH THE WEEKEND. IN FACT...THEY BOTH INDICATE
MULTIPLE 6-HR PERIODS OF MODERATE TO HEAVY RAIN. THUS THE CHANCES
FOR PRECIPITATION HAVE BEEN INCREASED 10-20 PERCENTAGE POINTS ABOVE
CLIMATOLOGY FRIDAY AND SATURDAY. CONFIDENCE IN RAIN RETURNING IS
HIGH...BUT RAIN AMOUNTS ARE STILL HIGHLY UNCERTAIN. IT SHOULD BE
NOTED THAT THE LAST TIME BOTH MODELS INDICATED A STORM WITH SUCH
CONSISTENCY IN THE 6-7 DAY TIME FRAME BOTH MODELS DROPPED THE
STORM WITHIN 24 HOURS. SO THERE IS STILL PLENTY OF POTENTIAL FOR
THINGS TO CHANGE. MODEL TRENDS WILL CONTINUE TO BE MONITORED. STAY
TUNED FOR UPDATES. RPA


&&

.AVIATION...BUILDING HIGH PRESSURE AND DEVELOPING OFFSHORE FLOW WILL
PRODUCE MOSTLY VFR CONDITIONS THROUGH SUNDAY. AREAS OF IFR IN FOG OR
LOW OVERCAST WILL PROBABLY DEVELOP IN THE INTERIOR VALLEYS THOUGH AS
THE LAND MASS COOLS OVERNIGHT.


&&

.MARINE...BUOYS ACROSS NORCAL WATERS HAVE BEEN RUNNING AROUND 11 FT
NEAR 11 SECONDS TODAY. OFFSHORE BUOY #2 HAS BEEN REPORTING SEAS OF
15 FT NEAR 15 SECONDS THROUGH THE DAY AS WELL. THESE REPORTS WERE IN
FAIRLY GOOD AGREEMENT WITH THE WAVE MODEL GUIDANCE WHICH HAS SEAS
CONTINUING AROUND 10 TO 12 FT TONIGHT THROUGH SUNDAY. THE DOMINANT
PERIODS HAVE BEEN RUNNING LOWER THAN FORECASTED. BRISK NW FLOW
BEHIND THE FRONT WILL EASE UP LATER TONIGHT AS HIGH PRESSURE BUILDS
INLAND AND AN OFFSHORE WIND FLOW DEVELOPS NEAR SHORE. WINDS ARE
EXPECTED TO REMAIN MAINLY LIGHT SUNDAY THROUGH MONDAY AS THE RIDGE
HOLDS OVER THE AREA AND A WARM FRONT APPROACHES AND CLIPS THE OUTER
WATERS WITH LIGHT TO MODERATE SOUTH WINDS. BEYOND MON...MODELS
INDICATE SEAS FALLING TUE INTO WED WITH NO SUBSTANTIAL CHANGE IN
WINDS. ON THU...SOUTHERLY FLOW WILL START TO RAMP UP AS A NEW LOW
PRESSURE SYSTEM APPROACHES THE AREA. CONFIDENCE IS NOT HIGH ON THE
TIMING AND MAGNITUDE. STRONGER WINDS MAY HOLD OFF TIL FRI OR SAT.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
     SMALL CRAFT ADVISORY UNTIL 2 AM PST MONDAY FOR
     PZZ450-455-470-475.

&&

$$

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