Area Forecast Discussion
Issued by NWS Eureka, CA

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FXUS66 KEKA 291245
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
445 AM PST MON DEC 29 2014

.SYNOPSIS...A REINFORCING COLD FRONT WILL BRING ANOTHER CHANCE
OF LIGHT SHOWERS NORTH OF CAPE MENDOCINO TODAY...FOLLOWED BY
MOSTLY DRY AND COLD CONDITIONS FOR THE REMAINDER OF THE WEEK.
EASTERLY WINDS WILL BE QUITE GUSTY TUESDAY THROUGH
WEDNESDAY...ESPECIALLY ACROSS THE HIGHER ELEVATIONS OF MENDOCINO
COUNTY.

&&

.DISCUSSION...ONCE AGAIN...VERY LIGHT RAIN IS BRUSHING THE N
PORTION OF THE AREA THIS MORNING WITH MORE SIGNIFICANT RADAR
ECHOES WELL TO THE N OVER NW OREGON. EARLY MORNING TEMPERATURES
ARE IN THE LOWER TO MID 40S ALONG THE COAST. SIMILAR TEMPERATURES
ARE ALSO OCCURRING OVER THE TRINITY HORN WHERE STRONGER N WINDS
ARE UNDERWAY ALONG WITH SOME THICKER CLOUDS. COLDEST TEMPERATURES
ARE FOUND OVER THE YOLLA BOLLYS WHERE READINGS ARE IN THE MID 20S
WITH LIGHT WINDS.

A REINFORCING COLD FRONT WILL DIVE INTO THE REGION FROM THE N AND
NE TONIGHT. MORE LIGHT SHOWERS ARE POSSIBLE...MAINLY N OF CAPE
MENDOCINO. AS SNOW LEVELS DROP BELOW 2K FT OVERNIGHT...VERY LIGHT
ACCUMULATIONS ARE POSSIBLE OVER THE N MOUNTAINS.

AN UPPER HIGH PRESSURE RIDGE OVER THE E PACIFIC WILL AMPLIFY INTO
MID-WEEK AS A NEARLY CUT OFF UPPER LOW DEVELOPS OVER SW NV AND
SHIFTS S. THIS WILL ALLOW COOL N-NE FLOW TO CONTINUE TO POUR INTO
THE AREA FROM NW CANADA. THE COLDEST WX OF THIS EARLY WINTER IS
EXPECTED THIS WEEK. MODELS CONTINUE TO TREND TOWARD TUE NIGHT
BEING THE COLDEST NIGHT ACROSS MOST OF THE AREA. HAVE CONTINUED
THE THINKING THAT WED NIGHT MAY EXPERIENCE SIMILAR LOWS...IF NOT A
BIT COLDER...DUE TO THE FACT THAT WINDS WILL BE LIGHTER WITH
BETTER RADIATIONAL COOLING.

SPEAKING OF WIND...THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE
OVER E OR AND AN INVERTED TROF NEAR THE CA COAST WILL TIGHTEN TUE
AND TUE NIGHT LEADING TO GUSTY WINDS ACROSS THE AREA...
PARTICULARLY ACROSS HIGHER ELEVATIONS OF MENDOCINO COUNTY. THE
STRONGEST WINDS APPEAR TO BE FOCUSED JUST S OF THE AREA DURING
THIS TIME. HAVE HELD OFF ON ISSUING A WIND ADVISORY...BUT THE DAY
SHIFT MAY HOIST ONE LATER TODAY. HAVE ADDED A MENTION TO THE HWO
THAT VALLEY WINDS MAY BE STRONGER IN VALLEYS ORIENTED PARALLEL TO
THE WIND.

THE NEXT CHANCE OF PRECIP APPEARS TO BE THIS WEEKEND...BUT THE
MODELS ARE NOT IN GOOD AGREEMENT. HAVE CONTINUED WITH NEAR CLIMO
POPS N OF THE CAPE AND BELOW CLIMO TO THE S. /SEC

&&

.AVIATION...VERY LIGHT RAIN ASSOCIATED WITH AN APPROACHING LOW
PRESSURE SYSTEM WILL IMPACT AIRFIELDS NORTH OF CAPE MENDOCINO EARLY
THIS MORNING. RAIN SHOWERS WILL BE SPARSE BUT COULD BRING CEILINGS
DOWN INTO THE MVFR CATEGORY. PATCHY FOG ACROSS INTERIOR VALLEYS WILL
BE SLOW TO CLEAR WITH MVFR AND IFR CONDITIONS IMPROVING BY LATE THIS
MORNING. THEN VFR WILL PREVAIL TODAY AS LIGHT RAIN SHIFTS SOUTHWARD
LEAVING MOSTLY SUNNY CONDITIONS ACROSS NWCA. MOSTLY VFR SHALL
PERSIST OVERNIGHT WITH PATCHY VALLEY EXPECTED TO DEVELOPMENT ONCE
AGAIN. KML

&&

.MARINE...NORTHERLY WINDS WILL SLOWLY INCREASE THROUGH TUESDAY AS A
DEVELOPING THERMAL TROUGH OVER CALIFORNIA AND BUILDING HIGH PRESSURE
OFFSHORE STRENGTHEN THE PRESSURE GRADIENT. AREAS DOWNWIND OF CAPE
MENDOCINO CAN EXPECT MARGINAL CONDITIONS WITH GUSTS NEARING 21 KT
EARLY TODAY. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE OUTER
WATERS STARTING LATE THIS AFTERNOON AS INCREASING WINDS AND SEAS
MEET CRITERIA. GUSTY WINDS AND STEEP SEAS WILL PERSIST INTO
WEDNESDAY SO THE ADVISORY WILL LIKELY NEED TO BE EXTENDED WEDNESDAY.
WINDS AND SEAS WILL EASE AGAIN LATE IN THE WEEK AS A DEEP, COLD
UPPER LEVEL TROUGH DIVES OVER CALIFORNIA AND HELPS BREAK DOWN THE
PRESSURE GRADIENT BY WEAKENING THE THERMAL TROUGH. KML

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
     SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM WED
      FOR PZZ470-475.

&&

$$

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