Special Marine Warning 4, NWS Eureka, CA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE EUREKA CA
912 PM PDT THU MAR 17 2011

.SYNOPSIS...THE WET AND COLD PATTERN CONTINUES INTO THE WEEKEND
AS A LARGE STORM SYSTEM LINGERS OFFSHORE.

&&

.UPDATE...OVERNIGHT AND FRIDAY MORNING FORECAST WAS AMENDED TO ADD
ISOLATED THUNDERSTORMS AND SMALL HAIL. THE THUNDERSTORMS WERE ALSO
ADDED TO THE EVENING UPDATE TO THE COASTAL WATERS FORECAST. THE
EVENING SATELLITE IMAGERY SHOWED ISOLATED THUNDERSTORMS ALONG THE
APPROACHING FRONTAL BOUNDARY. THERE WAS ALSO A REPORT OF SMALL
HAIL NEAR ALBION IN MENDOCINO COUNTY. KENNEDY

&&

.PREV DISCUSSION... /ISSUED 301 PM PDT THU MAR 17 2011/

DISCUSSION...MAIN CHANGES TO THE FCST TODAY WERE TO LOWER THE
ELEVATIONS OF THE WSW TO 2500 FT. SNOW LEVELS CURRENTLY NEAR 2000
FT...BUT WITH WARM ADVECTION AND GUSTY SOUTH WINDS TONIGHT AHEAD
OF THE NEXT FRONT...FREE AIR SNOW LEVELS WILL RISE A BIT. COLD AIR
TRAPPED IN VALLEYS WILL BE HARD TO SCOUR OUT AND THIS IS THE MAIN
REASON WHY WE THINK MORE ACCUMULATING SNOW MAY OCCURS DOWN TO 2500
FT. EVEN THOUGH THE WARNING ONLY GOES THROUGH FRIDAY
AFTERNOON...ACCUMULATING SNOW WILL CONTINUE FOR MUCH OF THE
WEEKEND AS A LARGE UPPER LOW DROPS OUT OF THE GULF OF ALASKA AND
MEANDERS OFF THE CA COAST.

CONVECTION IS THE OTHER CONCERN FOR THE NEXT COUPLE OF DAYS AS THE
COLD CORE OF THE UPPER LOW APPROACHES THE COAST WHILE MULTIPLE
SHORTWAVES PROVIDE SUFFICIENT DESTABILIZATION. THE MAIN THREAT FOR
ISO T BEGINS FRI AFTN AND CONTINUES THROUGH THE DAYLIGHT HRS ON
SAT. SMALL HAIL ACCOMPANYING ANY STORMS WILL BE THE BIGGEST
THREAT.

OVER THE WEEKEND...MODELS STILL HAVE A SECONDARY LOW SPINNING UP
SOUTH OF THE MAIN LOW...AND SWINGING TOWARD SF BAY ON SUN. THIS
WOULD TURN THE WINDS OFFSHORE FOR EXTREME NRN CA BUT FOCUS MORE
RAIN DOWN IN MENDOCINO CO. MORE CONFIDENCE IN THIS SOLUTION SO
HAVE BUMPED UP POPS INTO EARLY NEXT WEEK. TIMING OF THE EJECTION
OF THIS LOW COMPLEX IS STILL A QUESTION WITH GFS BEING THE SLOWEST
BUT PROBABLY IN THE SUN NIGHT-MON NIGHT TIME FRAME. JCA/DEAN

AVIATION...VFR TO MARGINAL VFR CONDITIONS EXPECTED ALONG THE COAST
DUE TO SAGGING CIGS AHEAD OF AN APPROACHING FRONT. COASTAL TERMINALS
WILL SEE GUSTY SOUTH WINDS AHEAD OF FRONTAL PASSAGE (JUST AFTER
MIDNIGHT) AND WILL LIKELY SEE BRIEF PERIODS OF VIS REDUCTION DUE TO
MODERATE OR HEAVY RAIN. INTERIOR SITES WILL REMAIN VFR FOR THE REMAINDER
OF THE DAY...BUT ALSO MAY SEE SOME MVFR CONDITIONS DEVELOP DUE RAIN
AND CIGS UPON FRONTAL PASSAGE AFTER MIDNIGHT. TONKIN

MARINE...A 995 MB LOW CURRENTLY OUT NEAR 47 138 WILL SLOWLY FILL
AS IT SLIDES NORTH...HOWEVER THE ASSOCIATED COLD FRONT IS MOVING
EASTWARD AND SHOULD APPROACH THE COASTAL WATERS AROUND 9PM TONIGHT.
THE FRONT WILL HANG UP A BIT BEFORE MAKING LAND FALL AFTER MIDNIGHT
THUS PEAK WINDS WILL LIKELY OCCUR BETWEEN MIDNIGHT AND 2AM. STILL
LOOKING AT GALE FORCE WINDS OVER MUCH OF THE COASTAL WATERS JUST
AHEAD OF AND DARNING FRONTAL PASSAGE WITH PEAK GUSTS AS HIGH AS 40
TO 50 KT IN FAVORED AREAS. WINDS WILL RAPIDLY DIMINISH BEHIND THE
FRONT AND BY SUNRISE WILL BARELY REACH SMALL CRAFT CRITERIA. THE NEXT
FOCUS WILL TURN TO A LARGE WESTERLY SWELL WHICH SHOULD BE FILTERING
THROUGH THE WATERS THROUGH THE WEEKEND...PEAKING TO NEAR 18 FT. THIS
SWELL WILL SUBSIDE BY SUN. FORECAST MODELS REMAIN IN FAIRLY GOOD
AGREEMENT ON DROPPING A LOW PRESSURE SYSTEM SOUTH OFF THE SONOMA
COAST ON SUNDAY WHICH WILL PROMOTE GUSTY OFFSHORE WINDS...ESPECIALLY
DOWN AROUND THE PT. ARENA AREA LATE SUNDAY. TONKIN

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 PM PDT FRIDAY
ABOVE 2500 FEET FOR THE CAZ003-004-076.

GALE WARNING UNTIL 5 AM PDT FRIDAY PZZ450-470-475.

SMALL CRAFT ADVISORY UNTIL 9 PM PDT SATURDAY PZZ455.

&&

VISIT US AT HTTP://WWW.WEATHER.GOV/EUREKA

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE EUREKA CA
321 PM PDT THU MAR 17 2011

CAZ001-002-182230-
REDWOOD COAST-MENDOCINO COAST-
321 PM PDT THU MAR 17 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHWEST CALIFORNIA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED TONIGHT.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

ISOLATED THUNDERSTORMS ARE EXPECTED FRIDAY AFTERNOON THROUGH
SATURDAY. SMALL HAIL WILL BE THE PRIMARY THREAT WITH ANY THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER TO THE
NATIONAL WEATHER SERVICE IN EUREKA.

CAZ003-004-076-182230-
NORTH COAST INTERIOR-UPPER TRINITY RIVER-MENDOCINO INTERIOR-
321 PM PDT THU MAR 17 2011

...WINTER STORM WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 6 PM PDT
FRIDAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHWEST CALIFORNIA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

A WINTER STORM WARNING IS CURRENTLY IN EFFECT. FOR FURTHER DETAILS
PLEASE REFER TO NOAA WEATHER RADIO OR WEATHER.GOV/EUREKA.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

A WINTER STORM WARNING IS CURRENTLY IN EFFECT THROUGH FRIDAY AFTERNOON.

ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE FRIDAY AFTERNOON THROUGH
SATURDAY...WITH THE PRIMARY THREAT BEING SMALL HAIL.

.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER TO THE
NATIONAL WEATHER SERVICE IN EUREKA.