Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 161705
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
1005 AM PDT TUE SEP 16 2014

.SYNOPSIS...AN APPROACHING LOW PRESSURE SYSTEM OVER THE EASTERN
PACIFIC WILL BRING A CHANCE FOR RAIN SHOWERS WEDNESDAY THROUGH
THURSDAY. WARM AND DRY WEATHER WILL RETURN OVER THE WEEKEND AS HIGH
PRESSURE BUILDS OVER NORTHERN CALIFORNIA.


&&

.UPDATE...CLOUD COVER IS SIGNIFICANTLY LOWER THAN ORIGINALLY
PREDICTED LAST NIGHT. A QUICK UPDATE HAS BEEN ISSUED TO REDUCE
CLOUD COVER ALONG THE COAST THROUGH THIS EVENING. RPA

&&

.PREV DISCUSSION......ISSUED AT 435 AM PDT...

SHORT TERM...(THRU THURSDAY) EARLY MORNING SATELLITE IMAGERY SHOWS
A BAND OF STRATUS OFFSHORE THAT IS SLIDING TOWARDS THE COAST.
EASTERLY FLOW IS HELPING TO KEEP PARTS OF THE COAST CLEAR OF CLOUD
COVER ESPECIALLY NORTH OF CAPE MENDOCINO WHILE AREAS TO THE SOUTH
ARE BEGINNING TO BE IMPACTED AS OF 10Z THIS MORNING. CLOUD COVER
WILL INCREASE ACROSS NORTHWESTERN CALIFORNIA OVERNIGHT AS THE UPPER
LEVEL TROUGH SLIDES TOWARDS THE WEST COAST. THIS LOW PRESSURE SYSTEM
WILL BRING A CHANCE FOR RAIN SHOWERS TO THE REGION WEDNESDAY THROUGH
THURSDAY. THE FIRST BAND OF ENERGY WILL IMPACT EARLY WEDNESDAY
MORNING LIKELY RESULTING IN DRIZZLE NEAR THE OR/CA BORDER. CHANCES
FOR PRECIPITATION WILL INCREASE WEDNESDAY AFTERNOON AS THE
LEADING EDGE OF THE LOW PRESSURE SYSTEM SLIDES OVER NORTHWESTERN
CALIFORNIA. RAIN SHOWERS WILL CONTINUE AS THE TROUGH SLIDES
OVERHEAD ON THURSDAY AND TAPER OFF LATER IN THE DAY. CONFIDENCE IS
NOT HIGH REGARDING THIS LOW BRINGING A LOT OF RAIN TO THE REGION
OR THAT IT WILL BE A LONG LASTING. MOST AREAS SHOULD OBSERVE ONLY
A FEW HUNDREDTHS OF AN INCH FROM THIS SYSTEM WHILE OTHER AREAS CAN SEE
AROUND ONE TENTH OF AN INCH. MORE FAVORABLE REGIONS INCLUDING
COASTAL AND SOME NEAR INTERIOR RIDGES MAY OBSERVE HIGHER RAINFALL
TOTALS. CONDITIONS SHOULD BEGIN TO DRY OUT AND STABILIZE QUICKLY
THURSDAY NIGHT AS HIGH PRESSURE BUILDS IN RAPIDLY BEHIND THE LOW.
KML

LONG TERM (FRIDAY THRU MONDAY)...HIGH PRESSURE WILL RAPIDLY BUILD
OVER NORTHERN CALIFORNIA FRIDAY AS THE UPPER LEVEL TROUGH DIVES
SOUTHWARD. THE GFS IS TRENDING TOWARDS THE ECMWF SOLUTION BY
DEVELOPING A CUT OFF LOW OVER SOUTHERN CALIFORNIA FOR THE WEEKEND.
THERE IS CONTINUED UNCERTAINTY WITH THE POSITIONING OF THE LOW BUT
BOTH SOLUTIONS NOW KEEP THE AREA DRY INTO EARLY NEXT WEEK WITH
BUILDING HEIGHTS AND ABOVE NORMAL HIGH TEMPERATURES RETURNING FOR
INTERIOR LOCATIONS. STPKML

AVIATION...A DRY UPPER LEVEL TROUGH MOVED THROUGH THE AREA
YESTERDAY. THE INCREASED MIXING AND OFFSHORE HAS MOST AREAS CLEAR
THIS MORNING. 11-3.9U SAT SHOWS A FAIRLY SIGNIFICANT STRATUS DECK
JUST OFFSHORE. EXPECT NORTH OF CAPE MENDOCINO SKIES WILL REMAIN
CLEAR THROUGH THE MORNING. THESE CLOUDS WILL LIKELY MOVE TOWARDS
THE COAST ONCE THE MIDDAY SEA BREEZE BRINGS A RETURN TO WESTERLY
WINDS. CONFIDENCE IS LOW ON THE TIMING OF THESE. SOUTH OF CAPE
MENDOCINO CLOUDS ARE CLOSER TO THE COAST AND WILL LIKELY MOVE IN
SOONER. INLAND AREAS ARE EXPECTED TO REMAIN CLEAR THROUGH THE DAY.
TONIGHT THE NEXT SYSTEM STARTS TO APPROACH THE AREA. THIS SHOULD
GRADUALLY LIFT CIGS OVERNIGHT...ALTHOUGH CONFIDENCE IS LOW ON THE
TIMING. MKK

MARINE...WINDS AND SEAS REMAIN QUITE LIGHT ACROSS THE WATERS. THE
MAIN WAVES ARE LONG PERIOD. THERE IS ONE AROUND 2 FT AT 16 SECONDS
OUT OF THE WEST/NORTHWEST. THE OTHER ONE IS AROUND 2 FT AT 21
SECONDS AND OUT OF THE SOUTHWEST. THE WEST/NORTHWEST SWELL WILL
BUILD IN TO AROUND 5 FT AT 14 SECONDS AND PEAK ON WEDNESDAY. THE
SOUTHWEST SWELL WILL PEAK AROUND 3 FT AT 20 SECONDS TODAY AND
SLOWLY DIMINISH THROUGH THE PERIOD. THESE WILL LIKELY BRING SOME
INCREASED CURRENTS WHICH COULD POSE A HAZARD FOR THOSE VENTURING
INTO THE SURF ZONE...SUCH AS ABALONE DIVERS.

WINDS WILL REMAIN SOUTHERLY AHEAD OF AN UPPER LEVEL TROUGH
APPROACHING THE AREA TODAY. THIS WILL DEVELOP A SMALL SHORT PERIOD
SOUTHERLY WAVE. SOUTHERLY WINDS LOOK TO PEAK LESS THAN 20 KT ON
WEDNESDAY WITH WAVES PEAKING AROUND 3 TO 4 FT AT 4 TO 5 SECONDS.
THURSDAY THE UPPER LEVEL TROUGH PASSES OVERHEAD AND WINDS BECOME
LIGHT AGAIN. THURSDAY NIGHT INTO FRIDAY HIGH PRESSURE LOOKS TO
RETURN TO THE AREA WITH NORTHERLY WINDS PICKING UP. FRIDAY WINDS
LOOK TO PEAK AROUND 25KT. WINDS WILL DIMINISH AGAIN FOR THE WEEKEND
AND INTO EARLY NEXT WEEK. MKK

&&

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

$$

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