Hazardous Seas Warning 30, NWS Eureka, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
427 AM PDT MON OCT 26 2009

.SYNOPSIS...A COLD FRONT WILL MOVE ACROSS THE AREA THIS AFTERNOON
BRINGING A CHANCE OF RAIN TO MOST OF NORTHWEST CALIFORNIA. HIGH
PRESSURE AND BRISK NORTHERLY WINDS WILL DEVELOP BEHIND THE FRONT
TONIGHT THROUGH TUESDAY.
&&

.DISCUSSION...AN UPPER TROUGH CURRENTLY NEAR 130W WILL MOVE ACROSS
THE PAC NW LATE TODAY. A COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL
PUSH ACROSS NW CA THIS AFTERNOON BRINGING RAIN TO THE REGION WITH
GREATEST CHANCES AND QPF OVER DEL NORTE COUNTY. DECENT CAA BEHIND
THE FRONT WITH 850MB TEMPS DROPPING TO AROUND -2C WILL ALLOW SNOW
LEVELS TO DROP TO 3000 TO 4000 FT OVERNIGHT. INSTABILITY SHOWERS
WILL PERSIST IN THE WAKE OF THE FRONT WITH A CHANCE RAIN AND SNOW
SHOWERS PERSISTING INTO TUE. BLUSTERY NORTHWEST AND NORTHERLY WINDS
BEHIND THE FRONT WILL INCREASE TONIGHT INTO TUESDAY...AS A 150+KT NW
JET DIVES INTO THE BACK SIDE OF THE UPPER TROUGH. EXPECT SHOWERS TO
DIMINISH TUE EVENING AS JET SHIFTS EAST AND UPPER RIDGE BUILDS INTO
THE E PAC. DRY WX EXPECTED TO PREVAIL THROUGH LATE WED NIGHT BEFORE
ANOTHER TROUGH OF LOW PRESSURE MOVES INTO THE PAC NW. RAIN CHANCES
INCREASE THU INTO FRI AS THE TROUGH AND ASSOCIATED FRONT PUSH ACROSS
THE REGION. FCST BECOMES MORE CHALLENGING BEYOND FRI. LATEST
GFSENS...CANADIAN AND ECMWF SHOW BROAD...WEAK RIDGING ACROSS THE W
CONUS BY SAT. GIVEN POOR RUN TO RUN CONSISTENCIES IN THE MODEL
OUTPUT AND WITH THE GENERAL TREND OF NW UPPER LEVEL FLOW...WILL
MAINTAIN POPS AROUND CLIMO THROUGH THE EXTENDED. BC
&&

.MARINE...A COLD FRONT WILL CROSS THE WATERS TODAY YIELDING SMALL
CRAFT ADVISORY CONDITIONS FOR ALL ZONES. LOOK FOR NEAR GALE
CONDITIONS IN THE SOUTHERN OUTER WATERS BY TUESDAY. THERE IS A GALE
WATCH OUT FOR ZONE 475 DURING THIS TIME FRAME. WINDS AND SEAS WILL
REMAIN UP INTO MIDWEEK. THEREFORE...EXPECT ROUGH CHOPPY SEAS. MODELS
REMAIN OUT OF ALIGNMENT AFTER MIDWEEK WITH REGARDS TO THE SURFACE
PATTERN. SO THE WINDS HAVE REMAINED SIMILAR TO THE PREVIOUS
AFTERNOON FORECAST. WILL ALLOW THE NEXT SHIFT ADJUST IF MODELS COME
INTO BETTER AGREEMENT. BFG
&&

.AVIATION...VISIBILITIES HAVE BEEN SLOW COME DOWN OVERNIGHT IN THE
COASTAL AREAS AS A MID LEVEL CLOUD LAYER HAS FILTERED THROUGH THE
REGION AHEAD OF TODAY/S COLD FRONT. A BREAK IN THE CLOUDS BEFORE
SUNRISE MAY HELP PROVIDE THE CATALYST FOR FOG DEVELOPMENT ALONG THE
COAST. CEC HAS BEEN SHOWING A SLOW REDUCTION OVER THE LAST COUPLE OF
HOURS. THE FORECAST REFLECTS LOWER VISIBILITIES EARLY THIS MORNING
AS A RESULT...BUT DOES NOT SHOW DENSE FOG. AT THIS POINT DONT THINK
THERE WILL BE SUFFICIENT TIME FOR DENSE FOG DEVELOP BEFORE SUNRISE
AND FRONTAL INFLUENCE. RAIN WILL DEVELOP LATER THIS MORNING INTO THE
AFTERNOON AS THE FRONT PASSES. THIS USHER IN A STRATUS LAYER IN THE
LOW LEVEL...THOUGH WITH NO SIGNIFICANT REDUCTION IN VISIBILITY. ONLY
IN HEAVIER SHOWERS WILL VISIBILITIES BE REDUCED. UKI WILL CONTINUE
IN VFR FOR THE MAJORITY OF THE DAY WITH HIGH CLOUDS PASSING OVER
THIS MORNING. LOOK FOR LOWERING CEILINGS LATER THIS AFTERNOON AS THE
FRONT DROPS TO THE SOUTHEAST BRINGING A SLIGHT CHANCE OF RAIN. LOOK
FOR POST FRONTAL WINDS TO INCREASE THROUGH ALL AIRPORTS. BFG
&&

.EKA WATCHES/WARNINGS...
SCA FOR WINDS AND SEAS ALL WATERS TONIGHT INTO WED
GALE WATCH FOR 475 TUE INTO EARLY WED
HAZ SEAS WATCH 475 TUE AND TUE NIGHT
&&

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