Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 250444
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
844 PM PST WED DEC 24 2014

.SYNOPSIS...NORTHWESTERLY WINDS WILL DECREASE THIS EVENING AS
A COLD FRONT MOVES FARTHER INLAND. COOLER AND DRIER CONDITIONS ARE
IN STORE FOR CHRISTMAS DAY AND BEYOND AS HIGH PRESSURE DELIVERS
BRISK AND DRY NORTHERLY FLOW TO THE REGION.


&&

.UPDATE...TEMPERATURES ARE DROPPING MORE QUICKLY THAN EXPECTED
ACROSS INTERIOR AREAS OF HUMBOLDT AND DEL NORTE COUNTIES. HAVE
ISSUED A FROST ADVISORY FOR THESE AREAS. A FEW LOCAL AREAS MAY
DROP BELOW FREEZING. AT THIS POINT THE COAST LOOKS TO STAY IN THE
MID TO UPPER 30S...BUT THIS WILL NEED TO BE MONITORED AS WELL WITH
TEMPERATURES ALREADY IN THE LOW 40S. A FEW OF THE COLDEST SPOTS ON
THE COAST MAY SEE SOME FROST...BUT FOR NOW CONFIDENCE IS NOW HIGH
ENOUGH FOR A FROST ADVISORY. THE SHOWERS WILL LIKELY KEEP THINGS
WELL ENOUGH MIXED TO NOT SEE ANY FROSTY TEMPERATURES. MKK

&&

.PREV DISCUSSION......ISSUED AT 307 PM PST...

DISCUSSION...A COLD FRONT HAS MOVED THROUGH THE AREA LEAVING
NORTHWEST FLOW OVER NORTHWEST CALIFORNIA. SHOWERS CONTINUE TO MIX
DOWN WIND GUSTS TO 45 MPH ALONG THE COAST AND IN THE NEAR COAST
MOUNTAINS. HIGH RESOLUTION MODELS INDICATE THAT THE WINDS WILL
DECREASE RAPIDLY THIS EVENING WITH WINDS BECOMING MUCH LIGHTER BY 10
PM. HAVE ISSUED A WIND ADVISORY TO COVER THE STRONGER GUSTS THROUGH
7 PM FOR THE NORTH COAST INTERIOR...REDWOOD COAST...AND MENDOCINO
COAST ZONES. SOME LINGERING SHOWERS ARE EXPECTED THROUGH THE
OVERNIGHT AS SNOW LEVELS CONTINUE TO FALL TO AROUND 2500 FEET. THIS
MAY ALLOW FOR SOME LIGHT SNOW ACCUMULATION DOWN TO PASS LEVELS. AT
THIS TIME ACCUMULATION IS EXPECTED TO REMAIN BELOW WINTER WEATHER
ADVISORY LEVELS WITH VERY MINIMAL ACCUMULATION ON ROADWAYS.
STILL...MOTORISTS SHOULD BE PREPARED FOR POSSIBLE SLICK ROADS
OVERNIGHT. ADDITIONALLY...IN LOCATIONS ACROSS INTERIOR NORTHWEST
CALIFORNIA WHERE TEMPERATURES FALL BELOW FREEZING TONIGHT...STANDING
WATER ON THE ROADS MAY FREEZE RESULTING IN BLACK ICE.

WITH THE MUCH COLDER AIR MASS SETTLING OVER THE REGION TOMORROW INTO
TOMORROW NIGHT...COLDER LOW TEMPERATURES ARE EXPECTED. THE COLDEST
NIGHT SO FAR THIS YEAR IS ANTICIPATED ACROSS HUMBOLDT AND DEL NORTE
COUNTIES. IN FACT...MANY AREAS OF INTERIOR HUMBOLDT AND INTERIOR DEL
NORTE HAVE THE POTENTIAL TO FALL BELOW FREEZING. THUS A FREEZE WATCH
HAS BEEN ISSUED FOR THE INTERIOR. ALONG THE COAST TEMPERATURES ARE
CURRENTLY ANTICIPATED TO FALL INTO THE MIDDLE TO UPPER 30S WHICH MAY
ALLOW FROST TO DEVELOP.

A SMALL RIDGE WILL BUILD OVER THE WEST COAST OVER THE WEEKEND
ALLOWING TEMPERATURES TO REBOUND SLIGHTLY. HOWEVER THE REBOUND WILL
BE SHORT LIVED AS ANOTHER COLD FRONT SLIDES DOWN THE WEST COAST.
THIS FRONT IS ANTICIPATED TO BE MOSTLY DRY EXCEPT FOR POSSIBLY SOME
SHOWERS OVER THE EXTREME NORTHERN PORTION OF THE COUNTY WARNING AREA
SATURDAY NIGHT OR SUNDAY MORNING.

VERY COLD AND DRY AIR WILL SETTLE OVER THE WESTERN UNITED STATES AS
A DEEP TROUGH DIVES INTO THE INTER-MOUNTAIN WEST BEHIND THE FRONT.
THIS WILL LEAVE NORTHWEST CALIFORNIA IN BROAD NORTH TO NORTH-
NORTHEASTERLY FLOW...AN IDEAL PATTERN TO ALLOW COLD AIR TO SPILL ALL
THE WAY TO THE COAST. HAVE OPTED TO AGAIN DECREASE TEMPERATURES FOR
MONDAY THROUGH WEDNESDAY NIGHT WITH LOWS NOW APPROACHING FREEZING
NEAR THE COAST EARLY NEXT WEEK. RPA

AVIATION...A POTENT COLD FRONTAL SYSTEM WILL EXIT THE REGION
TONIGHT. POST FRONTAL SCATTERED SHOWERS MAY CONTINUE TO GENERATE
DOWN BURSTS OF STRONG AND GUSTY NW WINDS THROUGH EARLY THIS EVENING.
HOWEVER THE STRONGEST WINDS HAVE BEEN WITH THE FRONT WHICH IS
SOUTHEAST OF THE AREA. WITH A COLDER AIR MASS AND MIXING IN THE
BOUNDARY LAYER TONIGHT...CIGS AND VSBY ARE EXPECTED STAY VFR. THERE
COULD BE BRIEF MISTY AIR CONDITIONS IN SOME OF THE VALLEYS THOUGH.

MARINE...A SURGE OF COLD AIR DOWN THE COAST WILL CONTINUE TO
PRODUCE STRONG AND GUSTY NORTHERLY WINDS THIS EVENING. THE WINDS
SHOULD EASE UP NORTH OF THE CAPE BY MID EVENING PER THE HIGHER
RESOLUTION DATA SETS. THE WINDS WILL REMAIN NEAR GALE IN THE
SOUTHERN WATERS THROUGH THE NIGHT...ESPECIALLY AROUND THE CAPE AND
IN THE OUTER WATERS. SEAS HAVE BE INCREASING THROUGH THE DAY AND
SHOULD CONTINUE TO BUILD THIS EVENING. ENP AND NWPS HAS SEAS HITTING
20 FT IN THE SOUTHERN WATERS AND 18 FT IN THE NORTHERN WATERS. THIS
SEEMS REASONABLE CONSIDERING THE STRENGTH OF THE WINDS. A WARNING
FOR SEAS MAY BE NECESSARY IF SWELL PERIODS DECREASE AFTER THE WINDS
DIE DOWN. WINDS WILL DECREASE ON THU...THOUGH IT WILL REMAIN
BORDERLINE FOR A GALE WARNING IN PZZ475. BY FRI...WINDS AND SEAS
SHOULD BEGIN TO DECREASE MORE SUBSTANTIALLY AS THE TROUGH ALOFT
HEADS EAST AND A BROAD FLAT RIDGE BUILDS OVER THE REGION. THE MODELS
WERE CONSISTENT IN SHOWING A REINFORCING SHOT OF COLD AIR EARLY NEXT
WEEK. ALL AGREE THIS NEXT FRONT WILL TRACK FARTHER TO THE EAST AND
INLAND OVER THE PAC NW. SO EVEN THOUGH WINDS WILL START TO COME UP
AS A HIGH PRESSURE RIDGE BUILDS OFFSHORE...THE NORTHERLY WINDS ARE
NOT EXPECTED TO BE AS STRONG WITH THIS THRUST OF COLD AIR ADVECTION
OVER LAND. THIS FLOW PATTERN WILL MOST LIKELY PROMOTE AN EASTERLY
AND NORTHEASTERLY FLOW REGIME NEAR SHORE AND OVER LAND.

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...
     FROST ADVISORY FROM 2 AM TO 8 AM PST THURSDAY FOR CAZ003.

     FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING FOR
     CAZ003.

NORTHWEST CALIFORNIA COASTAL WATERS...
     GALE WARNING UNTIL MIDNIGHT PST TONIGHT FOR PZZ455.

     SMALL CRAFT ADVISORY UNTIL 9 AM PST THURSDAY FOR PZZ450.

     GALE WARNING UNTIL 9 PM PST THIS EVENING FOR PZZ450-470.

     HAZARDOUS SEAS WARNING UNTIL 9 AM PST THURSDAY FOR PZZ450-470.

     SMALL CRAFT ADVISORY UNTIL 9 AM PST FRIDAY FOR PZZ410-470.

     GALE WARNING UNTIL 3 AM PST THURSDAY FOR PZZ475.

&&

$$

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