FXUS66 KEKA 261639 AAA
AFDEKA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE EUREKA CA
839 AM PST SAT DEC 26 2009

.SYNOPSIS...A WEAKENING FRONT WILL PRODUCE LIGHT RAIN ACROSS 
NORTHERN CA TODAY AND TONIGHT. LIGHT RAIN SHOWERS CAN BE EXPECTED 
FOR MOST OF THE WEEKEND. 

&&

.UPDATE...RAIN SHIELD SEEN OFFSHORE SHOULD APPROACH THE MENDOCINO
COAST BY LATE MORNING AND SPREAD FROM SOUTH TO NORTH ALONG THE
COAST THIS AFTERNOON. WE WILL UPDATE THE FCST TO TRY AND BETTER
DEFINE THIS TREND. STILL EXPECTING RELATIVELY LIGHT QPF AMOUNTS
(0.5 INCH OR LESS) THROUGH SUN MORNING. SOMETHING TO LOOK INTO FOR
THIS AFTERNOON ISSUANCE IS THE POSSIBILITY OF THUNDER OVER THE
WATER. THE SATELLITE IS SHOWING INSTABILITY UNDERNEATH THE UPPER
LOW CURRENTLY NEAR 41N 135W. WE WILL CLOSELY MONITOR THE
PROGRESSION OF THIS LOW DURING THE DAY AND MAKE AN UPDATES AS 
NECESSARY. JCA

&&

.PREV DISCUSSION... /ISSUED 326 AM PST SAT DEC 26 2009/ 

.DISCUSSION...LOW PRESSURE OVER THE NE PACIFIC CONTINUES TO PUSH
THE HIGH AMPLITUDE RIDGE EASTWARD. SATELLITE IMAGERY SHOWS THE
LEADING EDGE OF A CLOUD BAND ASSOCIATED WITH THE NEXT FRONT
NUDGING ITSELF ACROSS NORTHERN CA. THE FRONT IS CURRENTLY AROUND
100 NM OFFSHORE AND SHOWS SIGNS OF WEAKENING AS IT ENCOUNTERS THE
REMNANT DRY AIR FROM THE RIDGE. FORECAST IS ON TRACK WITH THIS
FRONT AND DID NOT MAKE ANY CHANGES TO THE TIMING OR AMOUNT OF
FORECASTED PRECIPITATION. SCATTERED SHOWERS ARE STILL EXPECTED TO
LINGER SUNDAY AND POSSIBLY INTO MONDAY MORNING AS THE LOW SHIFTS
INLAND. THERE WILL BE A BREAK IN RAIN PRODUCING WEATHER MONDAY
NIGHT AND TUESDAY WITH ANOTHER WEAK FRONT EXPECTED TUE NIGHT OR
WEDNESDAY. MODELS ARE STILL WORKING OUT THE DETAILS WITH THIS
SYSTEM...BUT ANTICIPATE ANOTHER LOW QPF EVENT. MODELS FORECAST
ANOTHER RIDGE TO DEVELOP OVER THE NE PACIFIC LATE IN THE WEEK BUT
VARY ON THE AXIS POSITION AND PRECIPITATION CHANCES...AND HAVE
MAINTAINED CLIMO POPS IN THE EXTENDED. TH

&&

AVIATION....MAINLY VFR CONDITIONS TO PREVAIL EARLY TODAY...ALTHOUGH 
LOCAL IFR-MVFR VISIBILITIES CAN BE EXPECTED IN AREAS OF COASTAL 
STRATUS AND ALSO INLAND VALLEY FOG. A WEAKENING FRONTAL BOUNDARY 
WILL THEN BRING OCCASIONAL MVFR CEILINGS AND VISIBILITIES IN  RAIN 
SHOWERS MAINLY AFTER 21Z TODAY...AND INTO MUCH OF TONIGHT.  BETTWY

&&

MARINE...SOUTHEASTERLY WINDS WILL CONTINUE TO INCREASE TODAY AS LOW 
PRESSURE APPROACHES THE WATERS. WIND SPEEDS WILL EASILY REACH SMALL 
CRAFT CRITERIA BY AFTERNOON ACROSS THE OUTER WATERS...WITH LOCAL 
SMALL CRAFT GUSTS LATE TODAY AND TONIGHT OVER THE INNER WATERS. 
WINDS WILL THEN BEGIN TO DECREASE LATE TONIGHT INTO SUNDAY AS A  
FRONTAL BOUNDARY SLIPS TO THE SOUTHEAST. THE BIG STORY REMAINS THE 
LARGE WESTERLY SWELL THAT WILL TRAVERSE THE WATERS. WE EXPECT THE 
SWELL TO PEAK AROUND 16 FEET AT 17 SECONDS TONIGHT INTO EARLY 
SUNDAY...AND THEN JUST SLOWLY SUBSIDE INTO MONDAY. THE ENP AND SWAN 
REMAIN TOO HIGH WITH THE PROJECTED SWELL AND SEA HEIGHTS...BUT WITH 
THE LONGER PERIOD SWELL...MARINERS ARE URGED TO EXERCISE EXTRA 
CAUTION IN AND AROUND HARBOR ENTRANCES WITH BREAKERS OF 18 TO 20 FT 
POSSIBLE BY LATE TODAY.  BETTWY

&&

.EKA WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 PM PST MONDAY PZZ450-455.
SMALL CRAFT ADVISORY UNTIL 2 PM PST MONDAY PZZ470-475.

&&

$$

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