275
FXUS66 KEKA 311012
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
212 AM PST SAT JAN 31 2026
SYNOPSIS
CHANCE FOR LIGHT RAIN AND DRIZZLE IS FORECAST FOR MOSTLY
DEL NORTE AND HUMBOLDT COUNTIES LATE SATURDAY NIGHT AND SUNDAY.
OTHERWISE, DRY AND STABLE WEATHER IS FORECAST TO CONTINUE THROUGH
MOST OF NEXT WEEK.
DISCUSSION
PLEASANT WEATHER WILL CONTINUE INTO THE
WEEKEND WITH MILD TEMPERATURES AND LOW ANGLE SUN. MID TO HIGH LEVEL
CLOUDS DO INDICATE THE APPROACH OF A LOW PRESSURE SYSTEM THAT WILL
JUST BARELY CLIP THE NORTHERN MOST AREAS OF THE CWA. PROBABILITIES
OF WETTING RAIN SUNDAY SEEM TO DIMINISH WITH EVERY MODEL RUN, THOUGH
SOME LIGHT PRECIPITATION IS STILL BEING FORECASTED.
THE HIGH AND MID CLOUD COVER WILL LIKELY COUNTERACT THE LONGWAVE
COOLING FOR THE INTERIOR VALLEYS WHILE HIGHER ELEVATIONS RESPOND TO
THE LARGE SCALE ADIABATIC WARMING. A STRONG NOCTURNAL INVERSION AND
MOIST GROUNDS WILL LIKELY RESULT IN FOG AND LOW CLOUDS EARLY SAT FOR
MOSTLY TRINITY, HUMBOLDT AND NORTHERN MENDOCINO COUNTIES.
DECAYING FRONTAL BOUNDARY WILL BRING A CHANCE FOR LIGHT RAIN OR
DRIZZLE TO PRIMARILY DEL NORTE AND HUMBOLDT COUNTIES LATE SATURDAY
NIGHT OR AFTER 2-4 AM SUNDAY. LIGHT RAIN OR DRIZZLE CHANCES INCREASE
AFTER 4 AM SUNDAY. HIGHEST CHANCE FOR 0.25 INCHES IN 12 HOURS END 4
PM SUNDAY IS FORECAST FOR DEL NORTE COUNTY, AROUND 40-50%. CHANCE
FOR > 0.25 INCHES IN 12 HOURS ENDING 4 PM SUNDAY IS MUCH LOWER FOR
MOST OF HUMBOLDT, 10-20%. CHANCE FOR > 0.10 INCHES IN 12 HOURS IS
NOT VERY MUCH HIGHER FOR MOST OF HUMBOLDT, GENERALLY AROUND 30-40%.
THAT IS A LONG WAY OF SAYING NOT MUCH RAIN IS EXPECTED. CHANCES FOR
0.01 TO 0.08 INCHES ARE HIGHER (>60%) AND WILL IMPACT OUTER
ACTIVITIES AND PROJECTS THAT CANNOT GET WET. TIMING AND DURATION
STILL REMAINS SOMEWHAT UNCERTAIN, BUT HIGHEST CHANCES SEEM TO BE
FROM 4 AM TO 12 PM SUNDAY. THE RAIN MAY NOT LAST AS LONG EITHER AS
THE FORECAST SEEMS TO SUGGEST. OTHER PORTIONS OF THE FORECAST AREA,
TRINITY AND MENDOCINO MAY SEE SOME LIGHT RAIN OR DRIZZLE TOO ON
SUNDAY, BUT RIGHT NOW WE ARE TALKING A TRACE TO PERHAPS A FEW
HUNDREDTHS. SOUTHEAST MENDO AND LAKE COUNTIES WILL MOST LIKELY NOT
GET ANY MEASURABLE RAIN. SAID ANOTHER WAY, AN 85% TO 95% CHANCE FOR
LESS THAN 0.01 INCHES IN 24 HOURS. THE SHORTWAVE TROUGH LIFTS OUT TO
THE NORTHEAST BY SUNDAY EVENING AND PRECIP CHANCE WILL START TO
DWINDLE EXCEPT FOR PERHAPS RESIDUAL DRIZZLE.
HIGH PRESSURE ALOFT WILL SPRING BACK UP BY MONDAY AND THEN DOMINATE
MOST ALL NEXT WEEK RESULTING IN MULTIPLE DAYS OF DRY AND STABLE
WEATHER. A SHALLOW MOIST AIR PUSH BEHIND THE FRONT AND N-NW SURFACE
FLOW MAY RESULT IN FOG AND LOW CLOUDS OVERNIGHT SUNDAY INTO MONDAY
MORNING IN THE INTERIOR VALLEYS. OTHERWISE, A GENERAL WARMING TREND
IS FORECAST FOR MUCH OF THE AREA EARLY TO MID NEXT WEEK. HIGHS ARE
FORECAST TO WARM UP INTO THE LOWER TO MID 70'S IN THE INTERIOR NEXT
WEEK. SOUTH FACING EXPOSURES AND HIGHER TERRAIN STAND THE BEST
CHANCE FOR HIGHS IN THE 70'S, WHILE VALLEYS TRAPPED UNDER THE
NOCTURNAL INVERSION WITH NIGHT AND MORNING FOG MAY NOT WARM UP EVEN
INTO THE LOWER 60S, ESPECIALLY IN TRINITY AND NORTHERN HUMBOLDT. THE
SUN ANGLE IS LOW AND MANY NARROW VALLEYS DO NOT GET MUCH OR ANY SUN
LIGHT THIS TIME OF YEAR. AS IS COMMON FOR THIS TIME OF YEAR,
OVERNIGHT LOW TEMPERATURES WILL REMAIN ON THE CHILLY SIDE WITH
SUBFREEZING MINIMUMS HIGHLY PROBABLE FOR VALLEYS IN TRINITY AND
PERHAPS PORTIONS HUMBOLDT, LAKE AND NORTHERN MENDO.
LONGER RANGE MODELS ARE SUGGESTING A BREAK-THROUGH IN THE WESTERLIES
OR UNDERCUTTING OF THE BLOCKING RIDGE LATE NEXT WEEK AND NEXT
WEEKEND. THIS COULD BRING US SOME RAIN. DETAILS ON THE TIMING AND
AMOUNTS ARE ELUSIVE AT THIS POINT. NBM 24-HOUR PROBABILITY OF
EXCEEDANCE FOR 1" IS NOT VERY HIGH, ONLY 5 TO 20%, ENDING 4 AM
SUNDAY. STAND BY FOR MORE IN THIS NEXT WEEK.
AVIATION
LIGHT OFFSHORE FLOW HAS CONTINUED TO PROMOTE VFR
CONDITIONS ALL ACROSS THE AREA THIS EVENING WITH BROKEN CLOUDS
AROUND 20 TO 25 KFT BEING THE ONLY NOTABLE FEATURE. SOME VERY
SHALLOW HAZE WILL BE POSSIBLE (20% CHANCE) ON THE COAST AROUND
SUNRISE, BUT OTHERWISE MORE CALM AND VFR CONDITIONS WILL PERSIST
SATURDAY. THIS INCREASED POTENTIAL FOR LIGHT COASTAL RAIN AND MVFR
CONDITIONS ALONG THE COAST BY EARLY SUNDAY MORNING. /JHW
MARINE
CURRENTLY GENTLE SOUTHERLY WINDS THROUGHOUT THE WATERS
WILL PERSIST THROUGH SATURDAY. THAT SAID, A PERSISTENT SERIES OF
LONG PERIOD WESTERLY SWELLS WILL MAINTAIN A STEEP SEA STATE.
COMBINED SEAS HAVE DROPPED BELOW 10 FEET, BUT ANOTHER WESTERLY SWELL
WILL BUILD IN AND KEEP SEAS NO SHORTER THAN ABOUT 8 FEET INTO THE
WEEKEND. A WEAK FRONT CROSSING THE AREA SUNDAY WILL REBUILD STEEP
SHORT PERIOD SEAS AT LEAST FOR THE NORTHERN WATERS. YET ANOTHER
ROUND OF STEEP, LONG PERIOD SWELLS WILL BUILD BEHIND THE FRONT
SUNDAY ONCE AGAIN BUILDING OVER 10 FEET INTO EARLY NEXT WEEK.
/JHW
BEACH HAZARDS
TWO LONG PERIOD (>16 SECONDS) WESTERLY SWELL GROUPS
WILL SPREAD INTO THE COASTAL WATERS THIS WEEKEND. THE FIRST ONE WILL
ARRIVE ON SATURDAY WITH HEIGHTS BUILDING TO 4 TO 6 FT AT 17 SECONDS
BY LATE AFTERNOON. A DECAYING WEST SWELL AROUND 6 FEET AT 11 SECONDS
WILL ALSO BE PRESENT AND SHOULD MITIGATE THE SNEAKER WAVE RISK.
ANOTHER LONG PERIOD SWELL TRAIN IS FORECAST TO ARRIVE ON SUNDAY WITH
SIGNIFICANT SWELL HEIGHTS BUILDING TO 12 FEET WITH PERIODS NEAR 16
SECONDS. BREAKERS UP TO 16 FEET FOR WEST AND NORTHWEST FACING
BEACHES ON SUNDAY ARE FORECAST BASED ON AVERAGE BEACH SLOPE
PROFILES. BEACHGOERS VENTURING NEAR THE SURF ZONE SHOULD REMAIN
VIGILANT. AVOID ROCKS, JETTIES AND STEEP BEACHES.
COASTAL FLOODING
CHANCE FOR MINOR HIGH TIDE FLOODING OF LOW-LYING
AREAS AROUND HUMBOLDT BAY WILL BE POSSIBLE SATURDAY AND AGAIN ON
SUNDAY. HIGHEST CHANCE (40%) FOR SALT WATER INUNDATION OF NORMALLY
DRY AREAS WILL BE ON SATURDAY, FOLLOWED BY SLIGHTLY LOWER CHANCES OF
30% ON SUNDAY. IMPACTS ARE NOT EXPECTED TO BE AS SEVERE AS THE KING
TIDE FLOODING OBSERVED IN EARLY JANUARY. MORE NUISANCE ROAD FLOODING
IS LIKELY IN AREAS LIKE KING SALMON. STORM SURGE MODEL HAS BEEN
FLUCTUATING AROUND FROM 8.7 TO 8.9 FT MLLW FOR SATURDAY AGAIN ON
SUNDAY. STRONG SOUTHERLY WINDS (>35 KT) AND LARGE SURF (>20 FEET)
WILL MAKE COASTAL FLOODING MUCH MORE SIGNIFICANT WITH GREATER
IMPACTS. THAT COMPONENT OF THE STORM SURGE CONTINUES TO BE LACKING
AND THEREFORE IMPACTS WILL MOST LIKELY BE MINOR WITH ROAD FLOODING
IN KING SALMON. WE POSTED A GRAPHIC ON OUR WEB PAGE TO CALL
ATTENTION TO THIS.
EKA WATCHES/WARNINGS/ADVISORIES
CA...
COASTAL FLOOD ADVISORY FROM 8 AM THIS MORNING TO NOON PST
TODAY FOR CAZ103.
NORTHWEST CALIFORNIA COASTAL WATERS...
COASTAL FLOOD ADVISORY FROM 8 AM THIS MORNING TO NOON PST
TODAY FOR PZZ415.
SMALL CRAFT ADVISORY FROM 8 AM SUNDAY TO 3 AM PST MONDAY
FOR PZZ450-455.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 3 AM PST
MONDAY FOR PZZ470-475.
NOTE: THE FULL FORECAST DISCUSSION IS NOW REGULARLY ISSUED BETWEEN
10 AM/PM AND 1 PM/AM. ADDITIONAL UPDATES WILL BE ISSUED AS NEEDED.
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