566
FXUS66 KEKA 162250
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
250 PM PST SUN FEB 16 2025
SYNOPSIS
SHOWER ACTIVITY CONTINUES THIS AFTERNOON THROUGH MONDAY
AFTERNOON, FOLLOWED BY BRIEFLY DRIER AND CALM WEATHER ON TUESDAY.
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
ISOLATED TO SCATTERED SHOWERS WILL CONTINUE TO MOVE
ONSHORE THIS 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, A 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 HOVER AROUND 5000 FEET
WEDNESDAY MORNING, LOWERING TO 4000 FEET BY WEDNESDAY EVENING.
LINGERING SHOWERS ARE EXPECTED TO TAPER OFF WEDNESDAY EVENING AS
HIGH PRESSURE BUILDS IN ALOFT.
LONG RANGE ENSEMBLES REMAIN IN GOOD AGREEMENT THAT A LONG PERIOD OF
DRY AND WARM WEATHER IS EXPECTED TO SETTLE 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
ADDITIONAL SHOWERS ARE EXPECTED THIS EVENING IN DEL
NORTE AND HUMBOLDT COUNTIES WHILE AREAS FARTHER SOUTH IN MENDOCINO
AND LAKE AND INLAND INTO TRINITY COUNTY DRY OUT. LIFR CEILINGS HAVE
DEVELOPED ALONG THE DEL NORTE COAST WHILE MVFR CEILINGS CONTINUE
FURTHER SOUTH. MVFR CEILINGS ARE EXPECTED TO PERSIST OVERNIGHT,
WHILE LIFR MAY IMPROVE TO MVFR AT KCEC LATE TONIGHT AS A WEAK
SHORTWAVE EMBEDDED IN THE UPPER FLOW DISRUPTS THE CLOUD LAYER
CURRENTLY ON THE SURFACE. CONFIDENCE IS LOW IN THIS OCCURRING, AND
LIFR MAY PERSIST OVERNIGHT.
MARINE
A QUICK MOVING FRONT HAS PASSED OVER THE AREA CAUSING
SSW WINDS TO DECREASE STEADILY IN ITS WAKE. SW WINDS ARE FORECASTED
TO PERSIST GETTING WEAKER OVER THE NEXT 48HRS. ANOTHER LOW PRESSURE
SYSTEM PASSING TO THE NORTH OF THE REDWOOD COASTAL WATERS TUESDAY
WILL FORCE FRESH BREEZE TO NEAR GALE WINDS WITH GALE FORCE GUSTS
TUESDAY EVENING INTO WEDNESDAY EARLY MORNING. BEYOND WEDNESDAY,
MODERATE TO FRESH BREEZES CAN BE EXPECTED AS A RIDGE OF HIGH
PRESSURE BUILDS AND WEAK THERMAL TROF CONDITIONS DEVELOP.
BUOY AND MODEL DATA SHOWS A LONG PERIOD SWELL EN ROUTE TO OUR
COASTAL WATERS RIGHT NOW. THE ETA FOR THIS SWELL IS AROUND MIDNIGHT
TONIGHT. THIS SWELL WILL PERSIST THROUGH TUESDAY. SMALL CRAFT
CONDITIONS DUE TO WIND AND WIND WAVES ARE POSSIBLE IN THE NORTHERN
OUTER WATERS LATE TUESDAY. MORE INFORMATION ON THIS EVENT AND
POSSIBLE HAZARD WILL BE AVAILABLE IN THE COMING DAY AS MODEL
GUIDANCE INCREASES IN CONFIDENCE.
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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