Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 222259
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
359 PM PDT TUE APR 22 2014

.SYNOPSIS...SHOWERS WILL DIMINISH THIS EVENING. OVERNIGHT A WARM
FRONT WILL START TO BRING RAIN NEAR THE OREGON AND CALIFORNIA
BORDER. THIS WILL SPREAD SOUTH WEDNESDAY AND THURSDAY. ADDITIONAL
SYSTEMS WILL BRING RAIN CHANCES THROUGH THE WEEKEND.

&&

.DISCUSSION...THE UPPER LEVEL TROUGH HAS MOVED OVER THE AREA TODAY.
IT BROUGHT FAIRLY WIDESPREAD SHOWERS THIS MORNING BUT THESE HAVE
SLOWLY DIMINISHED THROUGH THE DAY. THERE WERE A COUPLE REPORTS OF
BRIEF PERIODS OF SMALL HAIL. A FEW SHOWERS ARE LINGERING OVER THE
INTERIOR...BUT EXPECT THESE WILL DIMINISH ONCE THE SUN GOES DOWN.
TONIGHT A WARM FRONT IS EXPECTED TO START BRINGING SOME LIGHT RAIN
OR DRIZZLE TO MAINLY DEL NORTE COUNTY...ALTHOUGH CLOUDS WILL
SPREAD A BIT FARTHER SOUTH. SNOW LEVELS WILL BE LOW
TONIGHT...AROUND 3000 TO 3500 FEET. TONIGHT LOW TEMPERATURES ARE A
CHALLENGE. WENT WITH A FROST ADVISORY FOR INTERIOR MENDOCINO
COUNTY. UKIAH LOOKS TO STAY IN THE UPPER 30S BUT WILLITS...COVELO
AND RURAL OUTLYING AREAS MAY SEE SOME FROST. THE AIRMASS IN PLACE
IS FAIRLY DRY AND COOL...BUT THE WILD CARD IS THE CLOUD COVER.
INTERIOR TRINITY AND HUMBOLDT COUNTIES MAY SEE TEMPERATURES IN THE
MID 30S...BUT EXPECT THERE WILL BE ENOUGH CLOUD COVER TO INHIBIT
FROST FORMATION. THIS WILL NEED TO BE MONITORED THROUGH THE
EVENING HOURS.

WEDNESDAY THE WARM FRONT BECOMES MORE JUST ZONAL ONSHORE FLOW
WITH SOME SHORTWAVES MOVING THROUGH IT. THIS WILL ALLOW THE
PRECIP TO SPREAD FARTHER SOUTH...TO AROUND CAPE MENDOCINO THROUGH
THE DAY ON WEDNESDAY. SNOW LEVELS WILL RISE WEDNESDAY MORNING TO
AROUND 6000 FEET. RAINFALL AMOUNTS ARE EXPECTED TO BE LESS THAN A
HALF WEDNESDAY AFTERNOON AND EVENING. LATE WEDNESDAY NIGHT THE
RAIN PULLS BACK TO THE NORTH BEFORE STARTING TO MOVE SOUTH ON
THURSDAY AS A COLD FRONT. THIS WILL LIKELY SPREAD RAIN SOUTH INTO
MENDOCINO COUNTY.

THURSDAY NIGHT INTO FRIDAY THE NEXT UPPER LEVEL TROUGH STARTS TO
MOVE OVERHEARD. SNOW LEVELS WILL DROP TO AROUND 3500 FEET BEHIND
THE FRONT. SOME SNOW IS POSSIBLE ALTHOUGH AT THIS POINT CONFIDENCE
IS LOW ON AMOUNTS. INTRODUCED A SLIGHT CHANCE OF THUNDERSTORMS FOR
FRIDAY. TEMPERATURES ALOFT ARE FAIRLY COLD...AROUND -31C AT 500
MB. THERE IS SOME DECENT INSTABILITY WITH LI`S NEAR 0 OR SLIGHTLY
BELOW AND CAPE OF A FEW HUNDRED J/KG. SOME SMALL HAIL IS POSSIBLE
AS WELL. THIS WILL NEED TO BE MONITORED AS IT GETS CLOSER.

FOR THE WEEKEND ANOTHER SYSTEM IS EXPECTED...ALTHOUGH TIMING IS
STILL A BIT IN QUESTION. AT THIS POINT IT LOOKS FAIRLY WEAK.
MONDAY AND TUESDAY THE 12Z ECMWF AND THE 18Z GFS SHOW THE RIDGE
BUILDING IN AND THINGS DRYING OUT. THE 12Z GFS KEPT SOME PRECIP
AROUND A BIT LONGER INTO MONDAY. SO BROUGHT SOME SLIGHT CHANCE
POPS IN ON MONDAY. MKK


&&

.AVIATION...22Z RADAR SHOWS SCATTERED SHOWERS ACROSS NORTHWEST
CALIFORNIA AND THESE ARE FORECAST TO DISSIPATE THIS EVENING. THE
EXCEPTION IS NEAR THE CA/OR BORDER WHERE PRECIPITATION SHOULD
CONTINUE INTO TONIGHT AS A WEAK DISTURBANCE PASSES TO OUR NORTH.
TEMPO MVFR IS POSSIBLE IN SOME OF THE HEAVIER SHOWERS IN THIS AREA.

&&

.MARINE...NEARSHORE BUOY OBSERVATIONS THIS AFTERNOON ARE REPORTING
LIGHT WINDS AND SEAS AROUND 9-10 FT. THERE WAS NO ASCAT PASS OVER
OUR WATERS. MODELS REMAIN IN GOOD AGREEMENT SHOWING A SERIES OF
SYSTEMS PASSING MAINLY TO OUR NORTH THIS WEEK AND BRINGING PERIODS
OF MODERATE WINDS, MAINLY TO THE NORTHERN WATERS. OFFSHORE BUOY #2
REPORTED WAVE HEIGHTS OF 14 FT AT 13 SECONDS THIS AFTERNOON. SWELL
DECAY CALCULATION PUTS THIS NEAR 11 FT FOR OUR WATERS THIS EVENING.
ISSUED A SCA FOR THIS, BUT HELD OFF ON ZONE 455 WHERE IT APPEARS TO
BE MARGINAL. WINDS WILL ALSO BECOME GUSTY NORTH OF CAPE MENDOCINO
THIS EVENING INTO WEDNESDAY AS A DISTURBANCE PASSES THROUGH. LONG
PERIOD WESTERLY SWELL GENERATED FROM A DISTANT STORM SHOULD BEGIN
MOVING THROUGH OUR WATERS LATE THURSDAY INTO FRIDAY. WE WILL KNOW
MORE WHEN IT PASSES SOME OFFSHORE BUOYS. THE LONG PERIOD SOUTHERLY
SWELL THE MODELS ARE SHOWING FOR THIS WEEKEND SEEMS HIGH AND IT`S
DIFFICULT TO DETERMINE WHAT SOUTHERN HEMISPHERE STORM IS GENERATING
THEM. FOLLOWING INTERNAL COORDINATION, DECIDED TO CUT IT BACK IN THE
FORECAST UNTIL IT STARTS PASSING SOME SOUTHERN CALIFORNIA BUOYS.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
 SMALL CRAFT ADVISORY FROM 3 AM TO 9 PM PDT WEDNESDAY PZZ450-470-475.

&&

$$

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