Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 272330
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
330 PM PST SAT DEC 27 2014

.SYNOPSIS...A FRONT WILL MOVE THROUGH NORTHWEST CALIFORNIA
OVERNIGHT BRINGING A CHANCE OF LIGHT SHOWERS TO AREAS NORTH OF
CAPE MENDOCINO. OTHERWISE MOSTLY DRY AND COLD CONDITIONS ARE
EXPECTED FOR FOR MUCH OF THE NEXT WEEK.

&&

.SHORT TERM...(THROUGH TUESDAY NIGHT) THE NEXT COLD FRONT IS MOVING
INTO THE PACIFIC NORTHWEST AND WILL SLIDE DOWN THE COAST INTO
NORTHWEST CALIFORNIA TONIGHT INTO SUNDAY. A BAND OF PRECIPITATION IS
INDICATED ON RADAR IN OREGON AND SOUTHERN WASHINGTON AHEAD OF THIS
FRONT AND MAY SPREAD INTO THE NORTHERN REACHES OF NORTHWEST
CALIFORNIA TONIGHT AND/OR EARLY SUNDAY. MODELS ARE IN GENERAL
AGREEMENT OF A FEW HUNDREDTHS STRETCHING INTO AS FAR SOUTH AS
CENTRAL HUMBOLDT AND WESTERN TRINITY COUNTIES AS THE FRONT WEAKENS.
WITH COLD TEMPERATURES STILL LINGERING...SOME SNOW SHOWERS WILL
LIKELY FALL IN THE HIGHER ELEVATIONS WITH VERY LITTLE ACCUMULATION.
OVERNIGHT LOWS WILL BE SEVERAL DEGREES WARMER TONIGHT AS CLOUDS MOVE
OVER THE AREA RESTRICTING RADIATIONAL COOLING.

ANY LINGERING SHOWERS WILL DISSIPATE LATE SUNDAY MORNING/EARLY
AFTERNOON WITH THE FRONT MOVING SOUTH OF NORTHWEST CALIFORNIA.
ANOTHER COLD NIGHT IS IN STORE SUNDAY NIGHT AS SKIES CLEAR. THE
CLEAR SKIES WILL ALSO SUPPORT SOME INTERIOR VALLEY FOG DEVELOPMENT.

BY MONDAY ANOTHER MUCH STRONGER COLD FRONT WILL DIVE DOWN THE WEST
COAST AS A DEEP WESTERN US TROUGH DEVELOPS OVER THE INTER-MOUNTAIN
WEST IN RESPONSE TO A BUILDING RIDGE OFF THE WEST COAST. A FEW
SHOWERS WILL BE POSSIBLE IN DEL NORTE AND COASTAL HUMBOLDT WITH AND
JUST BEHIND THE FRONT AS COLD AIR MOVES OVER THE WARM COASTAL
WATERS. SNOW LEVELS WILL RAPIDLY FALL TO NEAR 2000 FEET WHICH COULD
ALLOW SOME NEAR COAST RIDGES TO SEE SOME FLAKES...BUT ONCE AGAIN
VERY LITTLE IF ANY ACCUMULATION IS EXPECTED.

THE COLD AIR MASS BEHIND THIS FRONT WILL BE SIGNIFICANTLY COLDER
THAN THE LAST COUPLE OF NIGHTS RESULTING IN LOWS FALLING INTO THE
20S AND TEENS ACROSS THE INTERIOR AND NEAR OR POSSIBLY BELOW
FREEZING AT THE COAST TUESDAY MORNING. THE PRIMARILY MITIGATING
FACTOR TO COLD TEMPERATURES WILL BE A STRONG OFFSHORE PRESSURE
GRADIENT LATE MONDAY NIGHT THROUGH TUESDAY NIGHT BEHIND THE FRONT AS
AN UPPER LOW ATTEMPTS TO CUT OFF OVER CENTRAL CALIFORNIA. THIS MAY
ALLOW SOME MIXING HOLDING TEMPERATURES UP A FEW DEGREES. RPA

.LONG TERM...(WEDNESDAY THROUGH SATURDAY) THE GFS AND EC ARE
CONSISTENT WITH THE LOCATION OF A STRONG BLOCKING RIDGE REACHING ALL
THE WAY TO ALASKA AND A CUT OFF LOW MIGRATING DOWN THE INTERIOR OF
CALIFORNIA...RESULTING IN NE FLOW OVER NORTHWEST CALIFORNIA. THIS
WILL ALLOW THE COLD AIR TO REMAIN IN PLACE AND TEMPERATURES TO
PLUMMET. THERE IS POTENTIAL FOR BELOW 30 DEGREE TEMPS TO APPROACH
COASTAL LOCATIONS WEDNESDAY AND THURSDAY MORNINGS. LOW LEVEL RH IS
ALSO VERY DRY TUE THROUGH THU. THE RAW GFS MODEL GUIDANCE SEEMED TO
REFLECT THE DRY AIR BEST. RIDGES WERE ADJUSTED DOWN SIGNIFICANTLY TO
REPRESENT THE VERY DRY AIR AT 925 AND 850 MB OVER THE RIDGES.

A GRADUAL WARM UP WILL BEGIN ON FRIDAY AS THE RIDGE NOSES TOWARD THE
COAST. A WEAK FRONT WILL LIKELY SAG TOWARD THE AREA OVER THE WEEKEND
BRING SOUTHERLY WINDS AND A CHANCE OF RAINFALL. TRN/RPA


&&

.AVIATION...NORTHERLY WINDS WILL GRADUALLY INCREASE UNTIL TUESDAY
NIGHT...POSSIBLY REACHING SMALL CRAFT CRITERIA BY MONDAY NIGHT OVER
THE OUTER WATERS...AS THE GRADIENT BETWEEN THE BLOCKING RIDGE AND
LOW TIGHTENS. WINDS WILL SHIFT TO NE AS THE LOW MOVES UNDER THE HIGH
ON WEDNESDAY. USED THE STRONGER GFS WINDS FOR THIS TIME PERIOD.
WINDS BECOME LIGHT AGAIN LATE IN THE WEEK AS AN INVERTED SURFACE
TROUGH MOVES ONSHORE. TRN


&&

.MARINE...VFR WILL CONTINUE AT ALL MAJOR REGIONAL AIRPORTS THROUGH
THIS EVENING, THOUGH MID TO HIGH CLOUDS WILL BE INCREASING FROM
NORTH TO SOUTH. A WEAK FRONTAL BOUNDARY WILL CLIP THE AREA OVERNIGHT
BRINGING A CHANCE OF RAIN TO CEC AND ACV. THIS WILL CAUSE CIGS TO
LOWER SLIGHTLY AND MAY DIP INTO MVFR FOR A TIME. MID TO HIGH LEVEL
CLOUDS WILL MOVE OVER THE REMAINDER OF THE REGION WITH THIS PASSING
BOUNDARY. BEHIND THIS BOUNDARY SKIES WILL CLEAR ALLOWING FOR VFR TO
DEVELOP AGAIN SUNDAY AFTERNOON. BFG


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&

$$

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