Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 192318
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
318 PM PST FRI DEC 19 2014

.SYNOPSIS...AN APPROACHING WARM FRONT WILL BRING RAIN TO THE
REGION LATE TONIGHT THROUGH THE WEEKEND. THEN...BUILDING HIGH
PRESSURE WILL DRY THE AREA OUT EARLY NEXT WEEK.

&&

SHORT TERM...(TODAY THRU SUNDAY) A FRONTAL BOUNDARY PASSED OVER THE
REGION EARLY THIS MORNING WITH SCATTERED POST FRONTAL SHOWERS
PERSISTING INTO THE AFTERNOON. INFRARED SATELLITE IMAGERY SHOWS A
LONG STREAM OF UPPER LEVEL MOISTURE BEE LINING IT TOWARDS THE
PACIFIC NORTHWEST. THE INITIAL WARM FRONT WILL ARRIVE LATE THIS
EVENING WITH CONSTANT WARM AIR AND MOISTURE ADVECTION THROUGH
SATURDAY. THIS ATMOSPHERIC RIVER WILL FOCUS MOST OF ITS ENERGY OVER
CENTRAL OREGON HOWEVER THE FORECAST CONFIDENCE TOOLS HAVE BEEN
CONSISTENTLY HIGHLIGHTING PWATS AND IVT VALUES 2 TO 3 STANDARD
DEVIATIONS ABOVE NORMAL ACROSS AREAS NORTH OF CAPE MENDOCINO
(ESPECIALLY DEL NORTE COUNTY). EVERYWHERE SOUTH OF THE CAPE LOOKS
LIKE IT WILL GET ADDITIONAL RAINFALL THIS WEEKEND HOWEVER CONFIDENCE
IS HIGHER FOR THE NORTH. RAINFALL TOTALS OVER THE WEEKEND WILL BE
HIGHEST ACROSS DEL NORTE COUNTY WITH 2 TO 3 INCHES POSSIBLE AND
NEARLY 4 INCHES OVER HIGHER TERRAIN. RAIN TOTALS WILL DECREASE
FARTHER SOUTH WITH 1 TO 2 INCHES ACROSS HUMBOLDT AND NEARLY 0.25
TO 1 INCH FOR EASTERN TRINITY AND MENDOCINO COUNTIES. CHANCES FOR
RAINFALL WILL DIMINISH ON SUNDAY AS BUILDING HIGH PRESSURE CUTS
OFF THE MOISTURE FLOW. SNOW LEVELS WILL BE NEAR 5,000 FEET TONIGHT
AND INCREASE THROUGH THE WEEKEND. KML

LONG TERM...(MONDAY THRU FRIDAY) BUILDING HIGH PRESSURE WILL DRY
THE REGION OUT EARLY NEXT WEEK. THE NEXT STORM IN SIGHT WILL DIVE
DOWN FROM THE BEARING SEA AND CLIP NORTHERN CALIFORNIA AS IT
CONTINUES TO TRACK EASTWARD. THE GFS AND ECMWF DIFFER IN THE
POSITIONING OF THE TROUGH WHICH MEANS DIFFERING OUTCOMES IN THE
TIMING OF PRECIPITATION AND SNOW LEVELS. THE ECMWF IS ABOUT 6
HOURS FASTER WITH THE PRECIPITATION BRINGING IT IN LATE WEDNESDAY
MORNING. THE ECMWF OUTCOME WOULD ALSO MEAN LOWER SNOW LEVELS
WEDNESDAY AND THURSDAY. AS FOR NOW THERE IS TOO MUCH UNCERTAINTY
WITH THE MODEL SPREAD AND THUS MAINTAINED ABOVE CLIMO POPS
WEDNESDAY AND SLOWLY TAPERED TO BELOW CLIMO POPS BY FRIDAY AS THE
LONG RANGE MODELS TREND TOWARDS BUILDING HEIGHTS. FURTHERMORE, WE
WILL NEED TO MONITOR THE POSSIBLILITY FOR THUNDERSTORMS WEDNESDAY
AFTERNOON AND EARLY EVENING WITH THE PASSING OF THE TROUGH. AS OF
RIGHT NOW IT IS STILL TOO EARLY TO TELL. KML

&&

.AVIATION...AS PROGRESSIVE PATTERN CONTINUES...WILL TRANSITION FROM
SHOWERY WX THIS AFTERNOON TO INCREASING WARM FRONTAL RAINS THIS
EVENING. CONDITIONS TODAY OUTSIDE OF RAIN SHOWERS SHOULD REMAIN
GENERALLY VFR. MVFR CONDITIONS WITH PERIODS OF IFR ARE POSSIBLE
TONIGHT AT KCEC AND KACV. WINDS WILL INCREASE AT COASTAL TAF SITES
LATE THIS EVENING...WITH GUSTS OVER 25 KTS AT KCEC BY SAT MORNING.
/SEC

&&

.MARINE...SEA STATE WILL REMAIN DOMINATED BY 2 LARGE WNW SWELL
TRAINS. THE 1ST SWELL TRAIN IS BUILDING INTO THE AREA NOW WITH
PERIODS OVER 20 SECONDS. THIS HAS PROMPTED AN AREA-WIDE HAZARDOUS
SEAS WARNING. IN ADDITION...WINDS IN THE N OFFSHORE WATERS WILL
REACH ADVISORY CRITERIA AFTER MIDNIGHT TONIGHT AS S WINDS INCREASE
AHEAD OF AN APPROACHING FRONTAL SYSTEM. THE N NEAR SHORE WATERS
AND S OFFSHORE WATERS WILL APPROACH ADVISORY CRITERIA AND WILL
NEED TO BE MONITORED. FOR NOW...IT APPEARS THE AREAL COVERAGE OF
ADVISORY LEVEL WINDS WILL NOT EXCEED 50% OF THE ZONES. FORERUNNERS
FROM THE 2ND SWELL TRAIN WILL ARRIVE BY EARLY MON WITH 21 SECOND
PERIODS. /SEC

&&

.SURF ZONE...A HIGH SURF ADVISORY REMAINS IN EFFECT THRU SAT
AFTERNOON FOR OUR ENTIRE COASTLINE. BREAKERS ARE LIKELY AROUND 22 FT
AT THE PRESENT TIME...RIGHT ON SCHEDULE. THESE BREAKERS ARE EXPECTED
TO FURTHER BUILD WITH SOME HEIGHTS REACHING 25 FT THIS EVENING.
BREAKERS ARE EXPECTED TO SLOWLY SUBSIDE ON SAT. /SEC

&&

.COASTAL FLOODING...HIGH TIDE THIS MORNING REACHED 8.7 FT WHICH
WAS 1.1 FT ABOVE THE PREDICTED LEVEL. WE RECEIVED A REPORT OF
MINOR FLOODING IN KING SALMON NEAR THE RV PARK. EXPECT MINOR
COASTAL FLOODING TO CONTINUE THROUGH THE WEEKEND DUE TO HIGH
ASTRONOMICAL TIDES AND PROLONGED SOUTHERLY WINDS. AN ADVISORY WILL
LIKELY BE NEEDED FOR THE NORTH COAST LATE SATURDAY MORNING BUT
WILL LET THE OVERNIGHT CREW ISSUE PRODUCTS. IN ADDITION TO SALT
WATER FLOODING AROUND HUMBOLDT BAY, LARGE SURF COINCIDING WITH THE
HIDE TIDE WILL ALLOW WAVES TO PUSH MUCH FARTHER UP BEACHES AND
POTENTIALLY IMPACT AREAS THAT TYPICALLY REMAIN DRY. KML

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     HIGH SURF ADVISORY UNTIL 6 PM PST SATURDAY FOR CAZ001-002.

NORTHWEST CALIFORNIA COASTAL WATERS...
     HIGH SURF ADVISORY UNTIL 6 PM PST SATURDAY FOR PZZ410-450-455.

     HAZARDOUS SEAS WARNING UNTIL 9 AM PST SATURDAY FOR
     PZZ450-455-470-475.

     SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 3 AM PST SUNDAY
     FOR PZZ470.

&&

$$

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