Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 052329
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
329 PM PST FRI FEB 5 2016

.SYNOPSIS...A WEAK FRONT WILL BRING ANOTHER CHANCE FOR LIGHT RAIN
THIS EVENING. HIGH PRESSURE IS BUILDING INTO THE AREA FOR THE
WEEKEND AND INTO EARLY NEXT WEEK BRINGING DRY WEATHER TO THE AREA.
ADDITIONAL RAIN IS POSSIBLE LATE IN THE WEEK.

&&

.SHORT TERM...VIS AND IR SAT SHOW THE COLD FRONT OFF THE COAST
THIS AFTERNOON. MODELS BRING THIS ONSHORE LATE THIS AFTERNOON AND
EVENING. RAINFALL AMOUNTS HAVE TRENDED DOWN...BUT SOME RAIN IS
STILL EXPECTED OVER HUMBOLDT AND DEL NORTE COUNTIES. AMOUNTS ARE
NOW LOOKING TO BE LESS THAN A QUARTER INCH OVER DEL NORTE COUNTY
WITH LESS THAN A TENTH OF AN INCH OVER MOST OF HUMBOLDT COUNTY.
SATURDAY CLOUDS WILL LINGER AROUND THE AREA AND MAY ACTUALLY
INCREASE IN THE AFTERNOON. THERE LOOKS TO BE A WEAK WARM FRONT
RIDING OVER THE RIDGE. THE NAM CONTINUES TO BE MORE AGGRESSIVE
WITH THIS AND IS SHOWING JUST A LITTLE BIT OF DRIZZLE SATURDAY
EVENING. THIS WILL NEED TO WATCHED IN CASE IT CONTINUES TO
STRENGTHEN AND BRING MORE WIDESPREAD DRIZZLE TO THE COAST.

SUNDAY MORNING ANY LINGERING MID LEVEL CLOUDS ARE EXPECTED TO MOVE
OUT OF THE AREA AS THE RIDGE BUILDS IN. THE INTERIOR VALLEYS WILL
LIKELY SEE SOME LOW CLOUDS AND FOG AS WELL...ALTHOUGH CONFIDENCE
IS LOW ON THE EXACT COVERAGE. HIGH TEMPERATURES WILL START TO WARM
ON SUNDAY INLAND AND AT THE COAST. OFFSHORE FLOW WILL BE WEAK BUT
MAY BE ENOUGH TO GET TEMPERATURES AT THE COAST INTO THE LOW 60S.
INLAND AREAS WILL MAINLY BE IN THE 60S TO MID 70S. AREAS THAT SEE
LOW CLOUDS AND FOG MAY STAY COOLER. THE MOST LIKELY PLACE FOR
THIS TO OCCUR IS IN THE WEAVERVILLE AREA SO KEPT THEIR HIGHS ONLY
AT 62. THE RIDGE IS QUITE STRONG MAKING THE AIR ALOFT WARM...BUT
THIS ALSO MAKES IT HARDER FOR THE INVERSION TO BREAK SO CONFIDENCE
IS LOW ON THE HIGH TEMPERATURES INLAND. THE WARMEST DAY IS
EXPECTED TO BE MONDAY.

.LONG TERM...TUESDAY THROUGH SATURDAY...THE OVERARCHING THEME IN THE
EXTENDED FORECAST WILL REVOLVE AROUND A GRADUAL PATTERN SHIFT FROM
AN AMPLIFIED LONGWAVE RIDGE ACROSS THE WEST COAST EARLY IN THE
WEEK...TO A SLIGHTLY MORE ACTIVE ZONAL FLOW REGIME LATER IN THE
WEEK. AS THE WEST COAST RIDGE BEGINS TO BREAK DOWN...SEVERAL
PROGRESSIVE SHORTWAVES WILL MOVE UP AND OVER THE RIDGE...WEAKENING
AS THEY DO SO. THE FIRST OF THESE WAVES WILL LIKELY APPROACH THE
COAST LATE WEDNESDAY/EARLY THURSDAY...PERHAPS HOLDING TOGETHER LONG
ENOUGH TO RESULT IN SOME LIGHT RAIN TO PARTS OF THE REGION.
CONFIDENCE IS LOW REGARDING THIS FIRST FRONT...HOWEVER...AS IT WILL
BE THE FIRST SYSTEM TO ENCOUNTER THE WEST COAST RIDGE AND MAY
STRUGGLE TO REACH THE COAST BEFORE DIMINISHING. THIS IS LESS OF A
CONCERN FOR THE NEXT SYSTEM LATE THURSDAY/EARLY FRIDAY...AS THIS
WAVE WILL LIKELY BE STRONGER THAN ITS PREDECESSOR WHILE THE RIDGE
WILL BE PROGRESSIVELY WEAKER. BEYOND FRIDAY...WHILE THE OVERALL FLOW
PATTERN WILL LIKELY TRANSITION INTO A MORE ACTIVE ZONAL FLOW
REGIME...THE NORTHERLY POSITION OF THE POLAR JET WILL LIKELY PUT THE
FOCUS OF PRECIPITATION FARTHER NORTH ACROSS THE PACIFIC
NORTHWEST...WITH PERIOD GLANCING BLOWS OF LIGHT TO MODERATE RAIN
AND SLIGHTLY COOLER TEMPERATURES ACROSS NORTHWEST CALIFORNIA.
/BRC

&&

.AVIATION...VFR CONDITIONS CAN BE FOUND ACROSS NORTHWEST
CALIFORNIA THIS AFTERNOON AS WE AWAIT THE ARRIVAL OF A WEAK COLD
FRONT. WINDS HAVE NOT BEEN AS STRONG AS PREVIOUSLY
THOUGHT...HOWEVER...ONCE THE FRONT ARRIVES WE SHOULD SEE WINDS
PICK UP AS THEY TURN MORE TOWARDS THE SOUTH...WITH GUSTS RANGING
FROM 15-20KTS POSSIBLE FOR COASTAL TERMINALS. LOWERING CIGS AND
VIS ARE EXPECTED FOR THE COASTAL TERMINALS AS WELL WHICH SHOULD
KEEP THEM IN MVFR FOR THIS EVENT...HOWEVER SOME BRIEF PERIODS OF
IFR COULD BE POSSIBLE BETWEEN 0Z-6Z DUE TO ONSET OF RAIN. KUKI HAS
A VERY SLIGHT CHANCE TO SEE SOME -RA OR -DZ...BUT CURRENT MODEL
DATA AND THINKING IS THAT PRECIP WILL STAY NORTH OF CAPE
MENDOCINO. KUKI DOES APPEAR TO HAVE A GOOD SHOT AT FALLING TO IFR
AND LIFR TONIGHT DUE TO FOG AND LOWERING CIGS...BUT THAT SHOULD
NOT HAPPEN UNTIL AFTER 9Z OR SO. ONCE THE FRONT EXITS LOOK FOR
CONDITIONS TO RETURN TO VFR FOR SATURDAY AFTERNOON. COME LATE
SATURDAY AFTERNOON INTO THE EVENING KCEC AND PERHAPS EVEN KACV
HAVE A SLIGHT CHANCE TO SEE SOME -DZ AND SOME LOWERING CIGS.
BC/KAR.

&&

.MARINE...SOUTHERLY WINDS HAVE INCREASED THROUGHOUT THE WATERS AHEAD
OF AN APPROACHING COLD FRONT THIS AFTERNOON...RESULTING IN BUILDING
STEEP SOUTHERLY WAVES IN ADDITION TO THE CONTINUING WESTERLY 10 FT
15 SECOND SWELL. THE STRONGEST WINDS...AND LIKEWISE THE LARGEST
SHORT PERIOD SEAS...REMAIN ACROSS PRIMARILY THE OFFSHORE WATERS
NORTH OF CAPE MENDOCINO WHERE FRESH BREEZES AND PERHAPS A FEW NEAR
GALE STRENGTH GUSTS WILL BE POSSIBLE. WINDS WILL LIKELY PEAK OVER
THE NEXT 2 TO 4 HOURS AND GRADUALLY DIMINISH LATE THIS EVENING AND
OVERNIGHT...ALLOWING THE STEEPER SOUTHERLY WAVES TO SETTLE.
MEANWHILE...THE PREVIOUSLY MENTIONED WESTERLY SWELL WILL CONTINUE TO
GRADUALLY DECAY THROUGH THE NIGHT...LIKELY FALLING BELOW 10 FEET BY
MID TO LATE MORNING TOMORROW.

THROUGH THE REMAINDER OF THE WEEKEND AND EARLY NEXT WEEK...LIGHT TO
MODERATE BREEZES WILL PREVAIL...WITH OFFSHORE FLOW BECOMING
NORTHERLY LATE SATURDAY THROUGH SUNDAY...AND BACK TO SOUTHERLY AHEAD
OF ANOTHER WEAK COLD FRONT TUESDAY. THIS WILL ALLOW THE SEA STATE TO
BE DOMINATED BY LONG PERIOD SWELL...WHICH MAY LEAD TO AN ENHANCED
SNEAKER WAVE THREAT ON MONDAY AS FORERUNNERS OF THE NEXT APPROACHING
SWELL TRAIN ARRIVE IN THE WATERS. /BRC

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
     SMALL CRAFT ADVISORY UNTIL 9 AM PST SATURDAY
     FOR PZZ450-455-470-475.

&&

$$

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