Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 302322
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
322 PM PST FRI JAN 30 2015

.SYNOPSIS...DRY WEATHER WILL CONTINUE THROUGH SATURDAY AS HIGH
PRESSURE REMAINS OVER THE REGION. A WEAK WEATHER SYSTEM WILL
BRING A CHANCE OF LIGHT RAIN LATE ON SUNDAY AND INTO MONDAY. A
WETTER PATTERN MAY BE IN STORE LATE NEXT WEEK.

&&

.DISCUSSION...VISIBLE SAT IMAGERY SHOWED THE LAST FEW STRANDS OF
STRATUS DISSIPATING AROUND HUMBODLT BAY THIS AFTERNOON. MODELS
CONTINUE TO INDICATE SLIGHTLY BETTER OFFSHORE FLOW SHAPING UP
TONIGHT AS AN INVERTED TROUGH FORMS NEAR THE COAST. SOME LOW
CLOUDS WILL PROBABLY STILL FORM TONIGHT...ESPECIALLY AROUND
HUMBOLDT BAY AND IN THE DELTA. ELSEWHERE SKIES WILL REMAIN MOSTLY
CLEAR INTO SATURDAY AS AN UPPER RIDGE BUILDS OVER THE AREA. THERE
WILL STILL BE SOME PATCHES OF FOG AND LOW CLOUD IN THE INTERIOR
VALLEYS...ESPECIALLY IN TRINITY COUNTY.

HIGH AND MID LEVEL CLOUDS...ASSOCIATED WITH A LOW PRESSURE SYSTEM
CURRENTLY WEST OF 140W...WILL MOVE OVER THE RIDGE ON SUNDAY. THE
MODELS CONTINUE TO SHOW A WEAKENING FRONT APPROACHING THE FAR
NORTH COAST...DEL NORTE COUNTY...DURING THE DAY ON SUNDAY. THE
MODELS CONTINUE TO SHOW THE FRONT WASHING OUT ALONG THE COAST BY
AFTERNOON. STILL NOT CONFIDENT THIS FRONT WILL GENERATE MUCH...IF
ANY...RAIN IN THE WARM AIR ADVECTION AHEAD OF THE SURFACE BOUNDARY.
THE FRONT WILL BE MOVING INTO A STRONG RIDGE AND SUSPECT THE RAIN
AMOUNTS THE MODELS HAVE ARE OVERDONE. STRONGER LOW LEVEL THETA-E
ADVECTION SHOULD DEVELOP SUN NIGHT INTO MONDAY WITH FAIRLY DECENT
ONSHORE FLOW NORTH OF CAPE MENDO. IF WE ARE GOING TO SEE ANY
RAIN...LATE SUN NIGHT AND MONDAY LOOK TO BE OUR BEST OPPORTUNITY
AS NEW SURFACE FRONT DEVELOPS AND HEADS TOWARD THE NORTH COAST.
PRECIP CHANCES HAVE BEEN BEEFED UP HERE...MAINLY ALONG THE NORTH
COAST AND OVER INTERIOR DEL NORTE COUNTY. FORECAST CONFIDENCE
REALLY STARTS TO ERODE GOING INTO TUE AND WED WITH BOTH THE GFS
AND ECMWF SHOWING MOIST WESTERLY FLOW INTO THE AREA. WILL EDGE
PRECIP CHANCES UPWARD SLIGHTLY...HOWEVER THE MODELS DO NOT HANDLE
THESE WARM/MOIST AIR ADVECTION PATTERNS VERY WELL AND IF ANYTHING
HAVE A TENDENCY TO BE WAY OVERBLOWN. NONE THE LESS AFTER SEVERAL
MODEL RUNS...IT CANNOT BE COMPLETELY IGNORED. ON WED A WARM FRONT
SHOULD LIFT NORTHWARD OUT OF THE AREA AS THE FLOW ALOFT AMPLIFIES
IN ADVANCE OF WHAT LOOKS TO BE A POTENT STORM SYSTEM. THIS STORM
IS SLATED TO AFFECT NW CAL THU NIGHT INTO FRI. THE GFS AND ECMWF
BOTH DRIVE A WET FRONTAL SYSTEM INTO NW CAL...PRODUCING BOUTS OF
MODERATE TO HEAVY RAIN. THE 12Z GFS HAS SEVERAL INCHES OF RAIN
ACCUMULATING THU INTO SAT. THE ECMWF WAS EQUALLY WET AND BULLISH
WITH THE RAIN. IN STARK CONTRAST...THE GEM HAS US DRY WITH
PRACTICALLY NO RAIN ON THU...AND JUST A FEW TENTHS CREEPING ONTO
THE COAST DURING THE DAY ON FRI. THE GEM TYPICALLY IS THE OUTLIER
AND SELDOM DOES IT PAN OUT DAYS 5 TO 7. FOR NOW WILL CONTINUE TO
PLAY IT CONSERVATIVELY AS THE MAJOR RAIN EVENT IS STILL 6 TO 7
DAYS OUT. WE HAVE SEEN TOO MANY TIMES THIS SEASON WHERE THE MODELS
HAVE BEEN WAY OFF ON THE RAIN AND WE ENDED UP GETTING NO RAIN OR
NOT QUITE AS MUCH 6 TO 7 DAYS OUT IN THE FUTURE. STAY TUNED.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED AT ALL TERMINALS THROUGH
TOMORROW AFTERNOON...AS VERY DRY AIR HAS SETTLED INTO THE REGION.
LIGHT OFFSHORE FLOW IS EXPECTED TO DEVELOP THIS EVENING AT BOTH
CEC AND ACV...AND WILL LIKELY PERSIST THROUGH THE OVERNIGHT AND
INTO THE DAY TOMORROW. AS SUCH...IT APPEARS UNLIKELY THAT FOG WILL
DEVELOP AT EITHER TERMINAL...ALTHOUGH IT REMAINS A SLIGHT POSSIBILITY
AT EITHER. PERSISTENCE EXPECTED AT UKI...WITH LIGHT NW WINDS AND
CLEAR SKIES ASIDE FROM A FEW LOW CLOUDS OVERNIGHT.

&&

.MARINE...FRESH TO STRONG NORTHERLY WINDS CONTINUE TO CREATE
STEEP...SHORT PERIOD SEAS ACROSS PRIMARILY THE OUTER WATERS THIS
AFTERNOON. WHILE MODEL GUIDANCE AND BUOY DATA SUGGESTS THAT THESE
WINDS HAVE REDUCED SLIGHTLY DURING THE MORNING AND AFTERNOON
HOURS...THEY ARE LIKELY TO INCREASE AGAIN DURING THE
CLIMATOLOGICALLY FAVORED EVENING TIME FRAME BEFORE GRADUALLY
SUBSIDING OVERNIGHT. IN THE MEANTIME...SHORT PERIOD SEAS ARE
EXPECTED TO CONTINUE ACROSS MUCH OF THE OUTER WATERS...AND MAY
EVEN PROPAGATE INTO PORTIONS OF THE INNER WATERS ALTHOUGH
CONFIDENCE DECREASES CLOSER TO SHORE. NO CHANGES WERE MADE TO THE
EXISTING SMALL CRAFT ADVISORY FOR THE OUTER WATERS...WHICH IS SET
TO EXPIRE BY 9 AM TOMORROW MORNING. IN ADDITION TO THE SHORT
PERIOD SEAS...A RESIDUAL WESTERLY SWELL WILL CONTINUE TO DECAY
THROUGH THE END OF THE WEEKEND...BEFORE BEING REINFORCED BY AN
ADDITIONAL SWELL GROUP APPROACHING EARLY IN THE WEEK. WHILE A FAST
MOVING STORM SYSTEM WILL BRUSH THE AREA TO THE NORTH ON MONDAY
...POTENTIALLY BRINGING MODERATE TO FRESH WINDS TO THE NORTHERN
OUTER WATERS...THE PREVIOUSLY MENTIONED SWELL IS EXPECTED TO BE
THE DOMINANT WAVE GROUP THROUGH THE MIDDLE OF THE WEEK.

ALL EYES THEN TURN TO AN APPROACHING STORM SYSTEM LATE IN THE WEEK.
MODEL GUIDANCE IS IN RELATIVELY GOOD AGREEMENT THAT GALE TO
POTENTIALLY STORM FORCE SOUTHERLY WINDS WILL ACCOMPANY THIS
STORM...ALONG WITH HEAVY SEAS...ALTHOUGH TIMING IS STILL A BIT
UNCERTAIN AT THIS EARLY JUNCTURE.  STILL...CONFIDENCE IS INCREASING
THAT MOST OF THE AREA WATERS...AND IN PARTICULAR THE NORTHERN
WATERS...WILL BECOME HAZARDOUS LATE IN THE WEEK AND INTO THE
WEEKEND.


&&

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
     SMALL CRAFT ADVISORY UNTIL 9 AM PST SATURDAY FOR PZZ470-475.

&&

$$

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