210
FXUS66 KEKA 312238
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
238 PM PST SAT JAN 31 2026
SYNOPSIS
LIGHT RAIN SHOWERS AND SPRINKLES IS FORECAST FOR
MOSTLY DEL NORTE AND HUMBOLDT COUNTIES LATE TONIGHT INTO SUNDAY.
OTHERWISE, DRY AND STABLE WEATHER IS FORECAST TO CONTINUE THROUGH
MOST OF NEXT WEEK.
DISCUSSION
VISIBLE SATELLITE IMAGERY DEPICT HIGH LEVEL CLOUDS
STREAMING ACROSS NORTHERN CALIFORNIA THIS AFTERNOON. SURFACE
OBSERVATIONS REPORTED HIGH TEMPERATURES GENERALLY IN THE MID
50'S TO MID 60'S, WITH THE EXCEPTION OF VALLEYS IN NE TRINITY
WHERE PREVAILING LOW CLOUDS REMAIN HIGHS IN THE MID 40S TO LOW
50S.
A SHORTWAVE TROUGH EMBEDDED TO A BROAD UPPER-LEVEL TROUGH OVER
THE NEPAC WILL SWING NORTHEASTWARD TOWARD NORTHERN CALIFORNIA AND
THE PACIFIC NORTHWEST TONIGHT INTO SUNDAY. A PUSH OF MOIST AIR
WITH AN ASSOCIATED PROGRESSIVE DECAYING FRONTAL SYSTEM WILL BRING
A CHANCE FOR LIGHT RAIN SHOWERS OR SPRINKLES TO PRIMARILY DEL NORTE
AND HUMBOLDT COUNTIES LATE TONIGHT OR AFTER 2-4 AM SUNDAY. THE HIGHEST
CHANCE FOR RAIN GREATER THAN 0.25 INCHES IN 12 HOURS ENDING 10 AM
SUNDAY IS FORECAST FOR DEL NORTE COUNTY, AROUND 40-50%. MUCH LOWER
CHANCE IS FORECAST FOR MOST OF HUMBOLDT, 10-20%. RAIN FORECAST
AMOUNTS RANGE FROM 0.25 TO 0.5 INCH FOR DEL NORTE COUNTY, WHILE
FEW HUNDREDTHS TO A QUARTER OF AN INCH ARE EXPECTED FOR HUMBOLDT
COUNTY. LIGHT SPRINKLES OR DRIZZLE ARE POSSIBLE TRINITY AND
NORTHERN MENDOCINO COUNTIES. DRY WEATHER WILL LIKELY PERSIST FOR
SOUTHERN MENDOCINO AND LAKE COUNTIES. CHANCES OF PRECIPITATION
DIMINISH QUICKLY THROUGHOUT THE DAY ON SUNDAY AS DRY AIR MASS
FILTER OVER THE AREA IN THE WAKE OF THE FRONT, PROMOTING A
GRADUAL CLEARING SKIES.
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. 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
MENDOCINO.
GLOBAL ENSEMBLES AND WPC CLUSTER GUIDANCES ARE SUGGESTING A
BREAK-THROUGH IN THE WESTERLIES OR UNDERCUTTING OF THE BLOCKING
RIDGE LATE NEXT WEEK AND NEXT WEEKEND. THIS HAVE THE POTENTIAL TO
BRING INCREASING CHANCES OF PRECIPITATION AND A COOLING TREND.
STAND BY FOR MORE IN THIS ON COMING NEXT WEEK. /ZVS
AVIATION
VFR WITH VARIABLE MID AND HIGH CLOUD COVER IS FORECAST
TO CONTINUE FOR TONIGHT AS A DECAYING FRONTAL BOUNDARY APPROACHES.
CHANCE FOR MVFR CONDITIONS AND RAIN INCREASES AFTER 12Z SUNDAY FOR
COASTAL TERMINALS. CHANCE FOR IFR WILL INCREASE AFTER FRONTAL
PASSAGE AS ONSHORE WINDS DEVELOPS, AFTER 18-20Z SUNDAY. KUKI WILL
LIKELY REMAIN VFR WITH ONLY HIGH OR SOME MID CLOUDS. INFLUX OF
SHALLOW MOIST AIR MAY BRING BETTER CHANCES FOR IFR SUNDAY NIGHT OR
EARLY MONDAY TO KUKI. OTHERWISE, CHANCE OF FOR FOG AND LOW CLOUDS
CONTINUE TONIGHT FOR VALLEYS IN TRINITY, HUMBOLDT AND NORTHERN
MENDOCINO. SLIGHTLY STRONGER MIXING WITH PREFRONTAL SOUTHERLIES OR
SOUTHEASTERLIES MAY LIMIT THE EXTENT AND DURATION OF FOG TONIGHT.
CHANCE FOR LOW LEVEL WIND SHEAR AND SHALLOW TURBULENCE WILL INCREASE
ACROSS THE MOUNTAINS OF DEL NORTE AND HUMBOLDT TONIGHT AND PERSIST
INTO SUNDAY MORNING WITH PASSAGE OF A FRONT. THE SHALLOW TURBULENCE
COULD HAVE AN IMPACT SMALL LIGHT-WEIGHT AIRCRAFT.
MARINE
SOUTHERLY WINDS INCREASE A NOTCH TONIGHT AS A DECAYING
FRONTAL BOUNDARY MOVES ACROSS THE WATERS. CHANCE FOR GUSTS > 20 KT
INCREASES TO 60-80% FROM ABOUT 11 PM TONIGHT TO 6 AM SUNDAY NORTH OF
CAPE MENDO. CHANCE FOR GUSTS > 25 KT ARE LOWER, AROUND 20-40% FOR
THAT SAME FRAME NORTH OF CAPE MENDO. WINDS SHOULD SHIFT AROUND TO SW
AND NW AFTER FRONTAL PASSAGE IN THE LATE MORNING AND AFTERNOON
SUNDAY AND REMAIN FAIRLY LIGHT, UNDER 10 KT. PRIMARY HAZARD WILL BE
SEAS AROUND 10 FT AND WILL WARRANT CONTINUATION OF THE ADVISORY FOR
SMALL CRAFT. THERE ARE MULTIPLE WAVE GROUPS COMING OUT OF THE NWPS.
THE ADVISORY FOR HAZARDOUS SEAS HINGES LARGELY ON STEEP SOUTHERLY
WAVES AROUND 5 TO 7 FEET. THESE WIND WAVES MAY BE TOO HIGH FOR WINDS
UNDER 15 KT AND A LIMITED FETCH AND DURATION. SHORT PERIOD WAVES
COMBINED WITH WESTERLY SWELLS AROUND 7 TO 9 FT WILL RESULT IN SEAS
AROUND 10 FEET. CONFIDENCE IS LOWEST FOR THE INNER WATERS WHERE
THERE IS MUCH MORE SPATIAL VARIABILITY. A LARGER WEST SWELL WILL
STEADILY BUILD THROUGH THE DAY ON SUNDAY AND EVENTUALLY REACH 11 TO
13 FEET AT 16 SECONDS BY SUNDAY EVENING. THIS SWELL WILL REMAIN
SUFFICIENTLY ELEVATED TO WARRANT EXTENSION OF THE ADVISORY FOR
HAZARDOUS SEAS INTO MONDAY. WESTERLY SWELL WILL SUBSIDE BELOW
CRITERIA BY TUE AS A FAIRLY TRANQUIL WIND REGIME PERSISTS FOR NW
CALIFORNIA COASTAL WATERS.
BEACH HAZARDS
TWO LONG PERIOD (>16 SECONDS) WESTERLY SWELL GROUPS
WILL SPREAD INTO THE COASTAL THIS WEEKEND. THE FIRST ONE IS EXPECTED
TO ARRIVE LATE THIS AFTERNOON AND BUILD TO AROUND 3 TO 4 FT.
SPECTRAL DENSITY PLOTS SO FAR SHOWED ALL THE ENERGY IN THE 11 SECOND
BAND. ANOTHER LONG PERIOD WESTERLY SWELL TRAIN ARRIVES ON SUNDAY
WITH HEIGHTS EVENTUALLY BUILDING TO 12 TO 14 FEET WITH PERIODS NEAR
16 SECONDS BY SUNDAY. THIS SWELL MAY BE TOO LARGE FOR SNEAKER WAVES,
THOUGH IT COULD STILL POSE A THREAT TO BEACHGOERS. BREAKERS UP TO 16
FEET FOR WEST AND NORTHWEST FACING BEACHES ARE FORECAST BASED ON
AVERAGE BEACH SLOPE PROFILES. BEACHGOERS VENTURING NEAR OR IN THE
SURF ZONE SUNDAY NIGHT OR EARLY MONDAY MORNING SHOULD REMAIN
VIGILANT. AVOID ROCKS, JETTIES AND STEEP BEACHES.
COASTAL FLOODING
HIGH ASTRONOMICAL TIDES ARE PREDICTED TO
CONTINUE ON SUNDAY. HIGH TIDES ARE FORECAST TO BE AT 8.22 FEET AT
THE NORTH SPIT TIDE GAUGE AT AROUND 10:42 AM LOCAL TIME ON SUNDAY.
HIGH TIDES COMBINE WITH SURGE AND TIDAL ANOMALY WILL RESULT IN
WATER LEVEL AT OR NEAR 8.8 FEET. MINOR COASTAL FLOODING AROUND
HUMBOLDT BAY, INCLUDING KING SALMON AND JACKSON RANCH ROAD IN THE
ARCATA BOTTOMS, WILL BE LIKELY BETWEEN 9AM AND 12PM. A COASTAL
FLOODING ADVISORY WILL BE IN EFFECT FROM 9AM TO 2PM MONDAY. HIGH
TIDES ARE PREDICTED TO BE AT 7.98 FEET @ 11:31 PM ON MONDAY. AT
THIS MOMENT, COMBINE WITH SURGE AND ANOMALY IS EXPECTED TO REMAIN
BELOW ADVISORY FOR MONDAY. /ZVS
EKA WATCHES/WARNINGS/ADVISORIES
CA...
COASTAL FLOOD ADVISORY FROM 9 AM TO NOON PST SUNDAY FOR
CAZ103.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY FROM 8 AM SUNDAY TO 4 PM PST MONDAY
FOR PZZ450-455.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 4 PM 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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FOR FORECAST ZONE INFORMATION
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