Area Forecast Discussion
Issued by NWS Eureka, CA

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000
FXUS66 KEKA 301056
AFDEKA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
356 AM PDT THU OCT 30 2014

.SYNOPSIS...A COLD FRONT WILL BRING RAIN TO THE REGION THURSDAY
EVENING INTO FRIDAY. ISOLATED THUNDERSTORMS WILL BE POSSIBLE
FRIDAY AFTERNOON AND NIGHT.

&&

.DISCUSSION...THIS MORNINGS PICTURES FROM SPACE LOOKING VERY MUCH
LIKE PREVIOUS MORNINGS WITH HIGH WARM SECTOR CLOUDS MOVING ACROSS
THE ETREME NORTHWEST PORTION OF THE CWA. AS OF 4AM RADAR RETURNS
SHOWING ONLY VERY LIGHT RAIN UNDER THESE CLOUDS WHILE REMAINING
WELL OFF THE COAST. THE FRONT THAT IS PROVIDING THE CLOUDS WILL
VERY GRADUALLY WORK EASTWARD APPROACHING THE COAST LATER TODAY.
MODELS IN GOOD AGREEMENT ON RAIN REACHING THE NORTH COAST
SOMEWHERE AROUND 6 OR 7PM...WITH WIDESPREAD RAIN OVER MOST OF THE
CWA JUST AFTER MIDNIGHT. A FEW HOURS OF MODERATE TO HEAVY RAIN IS
EXPECTED FOR ALL AREAS OF NORTHWEST CALIFORNIA RESULTING IN
PRECIPITATION TOTALS GENERALLY RANGING FROM 0.50 TO 1.5 INCHES
ACROSS THE AREA. THE COLD UPPER LEVEL CORE BEHIND THE FRONT WILL
MOVE OVER NORTHWEST CALIFORNIA FRIDAY AFTERNOON THROUGH FRIDAY
NIGHT INTO SATURDAY. THE BEST INSTABILITY LOOKS TO BE JUST BEHIND
THE FRONT DURING FRIDAY AFTERNOON AND NIGHT WITH NUMEROUS SHOWERS
EXPECTED TO DEVELOP OVER THE REGION. SNOW LEVELS WILL FALL TO NEAR
4500 FEET WHICH WILL ALLOW SOME OF THE MOUNTAINS TO RECEIVE SOME
LIGHT SNOW ACCUMULATION. ADDITIONALLY...WITH THE VERY COLD AIR
ALOFT...THE STRONGER SHOWERS OR STORMS WILL BE CAPABLE OF
PRODUCING SMALL HAIL AND ISOLATED LIGHTNING WHICH COULD IMPACT ANY
LOCATION IN NORTHWEST CALIFORNIA. MODELS CONTINUE TO BE CONSISTENT
WITH THIS SYSTEM...SO CONFIDENCE IN ITS EVOLUTION REMAINS HIGH.
THE MODELS HAVE ONCE AGAIN DIVERGED IN THE EXTENDED FORECAST WITH
THE GFS NOW INDICATING A VERY STRONG SHORTWAVE MOVING INTO THE
PACIFIC NORTHWEST MONDAY INTO TUESDAY WHICH COULD ALLOW A FRONT TO
SLIDE SOUTH INTO NORTHWEST CALIFORNIA. THE ECMWF IS MUCH WEAKER
WITH THIS SYSTEM AND FARTHER NORTH...THUS LEAVING NORTHWEST
CALIFORNIA DRY. FOR NOW HAVE OPTED TO KEEP SLIGHT CHANCES FOR
RAINFALL OVER THE FAR NORTHERN PORTIONS OF THE FORECAST AREA BUT
IN GENERAL HAVE KEPT THE FORECAST DRY SUNDAY THROUGH WEDNESDAY AS
RIDGING IS CURRENTLY THE PREFERRED SOLUTION IN THE ENSEMBLES.
RPA/JT

&&

.AVIATION...MID TO HIGH LEVEL CLOUDS IN ADVANCE OF AN APPROACHING
500MB TROUGH WILL SPREAD OVER THE REGION TODAY. INCREASING SOUTHERLY
AND SOUTHWEST FLOW IN THE WARM AIR ADVECTION AHEAD OF THE FRONT MAY
PRODUCE UPSLOPE TERRAIN-DRIVEN LIGHT SHOWERS AND MVFR CEILINGS THIS
AFTERNOON AND EARLY EVENING...MAINLY NEAR KCEC. THE BULK OF THE RAIN
AND MVFR CIGS WILL ARRIVE LATE TONIGHT INTO FRIDAY MORNING AS THE
FRONT MOVES ACROSS THE AREA. A BRIEF PERIOD OF MODERATE TO HEAVY
RAIN MAY DROP VSBYS TO 3SM OR LESS AT KACV AND KCEC AFTER MIDNIGHT
DURING FRONTAL PASSAGE...WITH WINDS SHIFTING AROUND TO THE WEST.
COLD AND UNSTABLE AIR WILL FOLLOW ON FRI AND PERSIST THROUGH FRI
NIGHT...BRINGING A THREAT OF ISOLATED TSTMS NEAR KACV AND KCEC.
DETERIORATING CONDITIONS ARE EXPECTED AT KUKI LATE TONIGHT INTO
FRIDAY MORNING.

&&

.MARINE...A COLD FRONT WILL APPROACH THE NORTHERN WATERS TODAY
BRINGING AN INCREASE IN SOUTH WINDS TO MAINLY THE OUTER WATERS.
WINDS SHOULD HIT 15-20 KT WITH PERHAPS A FEW HIGHER GUSTS. THE
SURFACE FRONT SHOULD WEAKEN AND WIND SPEEDS AND SEAS LOOK TO REMAIN
BELOW CRITERIA FOR A SMALL CRAFT ADVISORY. COLD AND UNSTABLE AIR
WILL FOLLOW ON FRIDAY AFTER THE FRONT PASSES INLAND AND WINDS SHIFT
AROUND TO THE W-NW BRIEFLY. A SURFACE TROUGH IN THE COOLER AIR MASS
WILL APPROACH ON FRI AND LOW TOPPED TSTMS WILL BE POSSIBLE. PROFILES
ARE NOT LOOKING ALL THAT FAVORABLE FOR STRONG LONG-LIVED STORMS. FRI
NIGHT MAY BE THE BEST OPPORTUNITY FOR STORMS AS THE SURFACE TROUGH
MOVES INTO THE WATERS. EVEN THOUGH WINDS ARE NOT FORECAST TO BE VERY
STRONG...THE CONVECTION MAY GENERATE LOCAL WINDS GUSTS TO 20-30KT.
NORTH FLOW SHOULD DEVELOP ON SAT AND INCREASE THROUGH THE DAY. THE
NAM12 AND GFS INDICATE SUSTAINED WINDS HITTING 20-25 KT IN THE FAR
SOUTHERN WATERS SOUTH OF CAPE MENDO. HOWEVER SEAS WILL ALREADY BE UP
TO 10 FT OR MORE ON SAT AND ADVISORIES FOR SMALL CRAFT WILL BE
NECESSARY IN ALL MARINE ZONES. THE SEAS WILL LIKELY BE A COMBINATION
OF A LONGER PERIOD WNW SWELL AND A SHORTER PERIOD WIND WAVE GROUP.


&&

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

$$

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