520
FXUS66 KEKA 161329
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
529 AM PST SUN FEB 16 2025
SYNOPSIS
SHOWERS ACTIVITY TODAY, INCREASING IN THE AFTERNOON
MAINLY IN DEL NORTE COUNTY. LINGERING SHOWERS MONDAY AFTERNOON,
FOLLOWED BY BRIEFLY DRIER AND CALM WEATHER THROUGH TUESDAY
AFTERNOON. ADDITIONAL RAIN IS EXPECTED TUESDAY NIGHT AND
WEDNESDAY. A LONG PERIOD OF DRY AND WARM WEATHER IS EXPECTED TO
START SETTLING IN BY END OF THE WORK WEEK.
DISCUSSION
A FRONTAL SYSTEM IS MOVING SOUTHEAST ACROSS THE
FORECAST AREA EARLY THIS MORNING. BREEZY SOUTHERLY WINDS HAVE
DEVELOPED ALONG THE NORTH COAST, WITH GUSTS OF 25 TO 40 MPH OVER
THE COASTAL HEADLAND AND EXPOSED RIDGES. RADAR IMAGERY DEPICTS A
BAND OF PRECIPITATION WITH LIGHT TO MODERATE RETURNS OVER THE
SOUTHERN MENDOCINO AND LAKE COUNTIES. ISOLATED TO SCATTERED
SHOWERS WILL MOVE INLAND THIS MORNING AND AFTERNOON, ESPECIALLY
ACROSS THE NORTHERN PORTION OF THE FORECAST AREA. CAMS SHOWS
SHOWERS ACTIVITY INCREASING IN DEL NORTE COUNTY LATE THIS
AFTERNOON AND EVENING, WITH PERIODS OF MODERATE RAINFALL. THE FAST
MOVING SHORTWAVE TROUGH IS EXPECTED TO EXIT EASTWARD THIS
EVENING, WITH LINGERING LIGHT SHOWERS THROUGH MONDAY AFTERNOON,
MAINLY ALONG THE NORTH COAST.
SNOW LEVELS WILL BE ABOVE 4500 FEET TODAY, WITH LIGHT MOISTURE
MOVING ACROSS THE AREA. SNOW LEVELS WILL COME DOWN AS THE UPPER
LEVEL SHORTWAVE TROUGH PASSES OVERHEAD AND BRINGS COLD AIR ALOFT,
GENERALLY DROPPING SNOW DOWN TO AROUND 3,500 TO 4,500 FEET TONIGHT
INTO MONDAY. SCOTT MOUNTAIN PASS ON HIGHWAY 3 WILL SEE SOME SNOW,
UP TO 2 INCHES.
MONDAY NIGHT INTO TUESDAY, DRY AIRMASS WILL MOVE ACROSS THE AREA
AS A SHORTWAVE RIDGE BUILDS IN. FOR AREAS WHERE SKIES CLEAR OUT
QUICKLY, AREAS OF VALLEY FOG ARE EXPECTED TO DEVELOP INTO TUESDAY.
OVERNIGHT TEMPERATURES ARE FORECAST TO RANGE FROM MID 30'S TO LOW
40'S, WITH LOWS IN THE UPPER 20'S TO LOW 30'S IN TRINITY COUNTY.
WARMER TEMPERATURES ARE EXPECTED ON TUESDAY AS THE RIDGE MOVES IN,
WHILE ANOTHER FRONTAL SYSTEM APPROACHES THE AREA FROM THE WEST.
PWAT VALUES ARE EXPECTED TO INCREASE TO 0.8 TO 1.0 INCHES ALONG
THE NORTH COAST LATE AFTERNOON/EARLY EVENING ON TUESDAY. RESULTING
IN SOME LIGHT RAIN SHOWERS MOVING INLAND ALONG THE NORTH COAST
TUESDAY EVENING.
A SHORTWAVE TROUGH AND ASSOCIATED FRONTAL SYSTEM WILL MOVE IN
TUESDAY NIGHT AND WEDNESDAY. SOUTH OF THAT FEATURE, A ZONE OF WAA
AND WEST- SOUTHWESTERLY MOISTURE FLUX WILL AID IN A REINFORCING OF
THE PRECIPITATION ACROSS THE NORTHERN HALF OF THE FORECAST AREA,
WITH MODERATE TO LOCALLY HEAVY RAINFALL OVER DEL NORTE AND FAR
NORTHERN HUMBOLDT LATE TUESDAY NIGHT INTO EARLY WEDNESDAY.
A COLDER AIR MASS WILL SUBSEQUENTLY SPREAD ACROSS THE WEST COAST
WEDNESDAY MORNING, WITH 500 MB TEMPERATURES OF -28C TO -30C. AS
RESULT, INSTABILITY WILL INCREASE TO AROUND 100- 200 J/KG OF CAPE
WEDNESDAY MORNING INTO EARLY AFTERNOON. INSTABILITY COULD ALLOW
FOR SOME ISOLATED LOW- TOPPED THUNDERSTORMS (10 TO 20% CHANCE)
OVER THE WATERS AND RIGHT ALONG SHORE, BUT ANY STORMS WILL BE WEAK
AND SHORT LIVED. THE GREATEST RISK FOR STORMS APPEARS TO BE NORTH
OF CAPE MENDOCINO. THE MAIN THREAT WILL BE LIGHTNING STRIKES AND
PERHAPS VERY BRIEF HEAVY DOWNPOURS. SNOW LEVELS ABOUT 5000 FEET
WEDNESDAY MONRING, LOWERING TO 4000 FEET WEDNESDAY EVENING.
LINGERING SHOWERS ARE EXPECTED TO TAPER OFF WEDNESDAY EVENING AS A
HIGH PRESSURE BUILDS IN.
LONG RANGE ENSEMBLES REMAIN IN GOOD AGREEMENT THAT A LONG PERIOD
OF DRY AND WARM WEATHER IS EXPECTED TO START SETTLING IN BY
THURSDAY. CLIMATE PREDICTION CENTER'S 6-10 DAY TEMPERATURES AND
PRECIPITATION OUTLOOK INDICATES 70-80% PROBABILITY OF ABOVE NORMAL
TEMPERATURES AND 50-60% BELOW NORMAL PRECIPITATION FOR THE WEST
BEGINNING NEXT WEEKEND. /ZVS
AVIATION
A COLD FRONT CONTINUES TO BRING RAIN TO PORTIONS OF
THE REGION THIS MORNING IN LAKE AND MENDOCINO COUNTIES. THE ACTUAL
BAND OF RAIN HAS ONLY RESULTED IN MARGINALLY LOWER CEILINGS, BUT
IN ITS WAKE LOWER CLOUDS HAVE SETTLED ONTO THE COAST AT ACV AND
CEC WHERE MVFR CONDITIONS HAVE DEVELOPED. ADDITIONAL SHOWERS ARE
EXPECTED TODAY IN DEL NORTE AND HUMBOLDT COUNTIES WHILE AREAS
FARTHER SOUTH IN MENDOCINO AND LAKE AND INLAND INTO TRINITY COUNTY
DRY OUT. STILL, CLOUD COVER WILL BE AN ISSUE WITH SHROUDED
RIDGETOPS AND MVFR CONDITIONS IN THESE AREAS AS WELL TODAY THROUGH
TONIGHT. /RPA
MARINE
SOUTHERLY WINDS HAVE PEAKED ACROSS THE WATERS AND WILL
GRADUALLY DECREASE TODAY. LATER TODAY A WEST-NORTHWESTERLY SWELL
WILL BUILD INTO THE WATERS AT 10-14 FEET LATE TONIGHT THROUGH
MONDAY. AS WIND SUBSIDES AND SEAS BUILD THERE WILL BE A BRIEF
PERIOD WHERE CONDITIONS MAY FALL BELOW SMALL CRAFT CRITERIA IN THE
NORTHERN OUTER WATERS ZONE, HOWEVER SEAS ARE EXPECTED TO REMAIN
AT OR JUST BELOW 10 FEET TODAY. SO, RATHER THAN DROP THE SMALL
CRAFT AND THEN IMMEDIATELY NEED TO REISSUE THIS MORNING, OPTED TO
EXTEND THAT ZONE'S SMALL CRAFT THROUGH THE DAY TODAY THROUGH
MONDAY WHEN THE NEXT SWELL BUILDS. ELSEWHERE, SMALL CRAFT
ADVISORIES BEGIN THIS EVENING.
SEAS WILL SUBSIDE MONDAY NIGHT INTO TUESDAY WITH LIGHT WINDS
ACROSS THE WATERS WITH A BRIEF PERIOD OF HIGH PRESSURE OVER THE
COASTAL WATERS. ANOTHER STORM SYSTEM WILL APPROACH THE WATERS
TUESDAY NIGHT BRINGING AN ADDITIONAL ROUND OF SMALL CRAFT TO NEAR
GALE SOUTHERLY WINDS TO THE WATERS INTO WEDNESDAY MORNING.
ADDITIONALLY, ANOTHER WESTERLY SWELL WILL LIKELY BUILD INTO THE
WATERS LATE IN THE WEEK. /RPA
BEACH HAZARDS
A WEST-NORTHWESTERLY SWELL WILL BUILD INTO THE
WATERS AT AROUND 10- 14 FEET AT 15 SECONDS EARLY MONDAY MORNING
AND THEN PERSIST THROUGH THE DAY. THE PERIOD AND HEIGHT OF THIS
SWELL IS RIGHT ON THE EDGE OF OUR CRITERIA FOR HIGHLIGHTING A
SNEAKER WAVE THREAT. SO, THOUGH NO HEADLINES ARE BEING ISSUED AT
THIS TIME, ANYONE GOING TO THE BEACH ON THE HOLIDAY MONDAY SHOULD
BE A LITTLE MORE CAUTIOUS AND WATCH FOR UNEXPECTEDLY HIGHER WAVE
RUNUP. /RPA
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 3 AM PST
TUESDAY FOR PZZ450-455-475.
SMALL CRAFT ADVISORY UNTIL 3 AM PST TUESDAY FOR PZZ470.
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