398
FXUS66 KEKA 051728
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
1028 AM PDT SAT SEP 5 2026
AVIATION 18Z UPDATE
STRATUS CAUSING IFR CONDITIONS ALONG THE
COAST AND WITHIN RIVER VALLEYS IS BEGINNING TO DISSIPATE LEADING
TO VFR SKIES FOR THE REGION TODAY. NORTHERLY WINDS ARE EXPECTED TO
BUILD THROUGH THE DAY ALONG THE COAST AND WITHIN VALLEYS. GUSTS
ARE POSSIBLE THIS AFTERNOON. CALM WINDS RETURN THIS EVENING WITH
AROUND A ~40% CHANCE OF IFR OR LOWER CEILINGS AT ACV THROUGH THE
LATE EVENING/EARLY MORNING. A DEEP MARINE LAYER SET UP WILL LIKELY
LEAD TO EARLY DISSIPATION AGAIN SUNDAY MORNING EXPECT FOR
EXTREMELY LOCALIZED AREAS OF STRATUS.
PREV DISCUSSION
/ISSUED 304 AM PDT SAT SEP 5 2026/
KEY MESSAGES...
- A GENERAL TROUGHING PATTERN TO THE NORTH WILL KEEP TEMPERATURES
COOL FOR THE INTERIOR
- PERIODS OF UNSETTLED WEATHER FOR DEL NORTE COUNTY AND EXTREME
NE HUMBOLDT AND TRINITY COUNTIES IS EXPECTED OVER THE WEEKEND.
- OVERNIGHT TEMPERATURES FOR THE INTERIOR WILL REMAIN CHILLY, YET
FOG FORMATION COULD INHIBIT ANY FROST FORMING WITHIN INLAND VALLEYS.
SYNOPSIS...A GENERAL TROUGHING PATTERN WILL KEEP INTERIOR
TEMPERATURES COOLER THAN AVERAGE AND CONTINUE AND UNSETTLED PATTERN
OVER THE REGION BRINGING A CHANCE FOR SHOWERS OR ISOLATED
THUNDERSTORMS THIS WEEKEND IN DEL NORTE AND EXTREME NE HUMBODLT AND
TRINITY COUNTIES. THIS UNSETTLED PATTERN COULD ALSO DISRUPT DIURNAL
COASTAL STRATUS THIS WEEKEND. COLDER MORNING TEMPERATURES COULD
OCCUR FOR THE COLDEST INTERIOR VALLEYS THIS MORNING WHEREVER FOG
DOES NOT FORM.
DISCUSSION...AN UPPER LEVEL TROUGH WILL CONTINUE TO LINGER OVER
THE PACIFIC NORTHWEST OVER THE WEEKEND. THIS FEATURE COULD AID IN
SPORADIC COASTAL STRATUS DEVELOPMENT ALONG THE COAST, LIGHT RAIN
SHOWERS FOR DEL NORTE AND EXTREME NE HUMBODLT AND TRINITY COUNTIES,
AND COOLER TEMPERATURES INLAND. SHORT WAVE DISTURBANCES ARE
ANTICIPATED TO FLOW DOWNSTREAM OVER NW CA THROUGH THE WEEKEND
INCREASING THE CHANCES FOR LIGHT RAIN SHOWERS, ESPECIALLY FOR
SUNDAY. THE INTERIOR WILL LIKELY SEE MORNING CLOUD COVERAGE
DISSIPATING TO COOLER TEMPERATURES THROUGH MONDAY. MORNING
TEMPERATURES FOR INTERIOR VALLEYS WILL BE COOLER TO COLDER THAN
AVERAGE OVER THE NEXT FEW DAYS WITH SOME OF THE CLIMATOLOGICALLY
COLDER VALLEYS REACHING MORNING LOW TEMPERATURES IN THE UPPER 30S TO
LOW 40S. HOWEVER, A FROST ADVISORY HAS NOT BEEN ISSUED DUE TO THE
LIKELIHOOD OF INSULATING CLOUD COVERAGE FOR MAJOR VALLEYS.
SUNDAY, A SHORTWAVE DISTURBANCE PASSING OVER THE FORECAST AREA IS
INCREASING THE RAINFALL CHANCES FOR THE DEL NORTE AND THE NORTHERN
PORTIONS OF TRINITY AND HUMBOLDT COUNTIES. A SLIGHT LIGHTNING CHANCE
EXISTS FOR THESE AREAS WELL, YET NW STORM MOTION WILL LIKELY CAUSE
ANY STORMS THAT DO FORM TO FLOW INTO SISKIYOU COUNTY QUICKLY. LITTLE
CHANCES FOR WETTING RAIN (>0.10") EXIST FOR AREAS AWAY FROM THE HIGH
TERRAIN INLAND FOR SUNDAY AS WELL.
A SLIGHT WARMUP IS POSSIBLE NEXT WEEK AS WELL, YET IF IT OCCURS, IT
SHOULD BE MILD AND SHORT LIVED AS TA TROUGHING PATTERN RETURNS AT
THE END OF THE COMING WORK WEEK. THERE ARE ALSO QUESTIONS ABOUT
WHETHER TROPICAL MOISTURE MAY STREAM NORTHEAST TOWARD THE REGION
FROM DECAYING TROPICAL SYSTEMS WELL OFF THE COAST. MODEL GUIDANCE
HAS A LARGE VARIANCE IN POSSIBILITIES RANGING FROM COMPLETELY DRY
AFTER SUNDAY TO SEVERAL CHANCES OF SHOWERS AND POSSIBLY
THUNDERSTORMS MID TO LATE WEEK.
MARINE...A CONTINUOUSLY EVOLVING LOW PRESSURE CENTER OVER
WESTERN OREGON IS BEGINNING TO WEAKEN. AS A RESULT, SOUTHERLY WINDS
WILL CONTINUE TO WEAKENING AND TURNING NORTHERLY BY EARLY THIS
MORNING. WAVES DURING THIS TIME ARE EXPECTED TO REMAIN BELOW SMALL
CRAFT ADVISORY CONDITIONS. NORTHERLIES ARE LIKELY TO BE BETWEEN 8-
12KTS WITH SPORADIC GUSTS UP TO 15KTS WITH THE STRONGEST WINDS IN
THE FAR NORTHERN WATERS DOWNWIND OF CAPE BLANCO AND IN THE SOUTHERN
WATERS DOWNWIND OF CAPE MENDOCINO. THE NORTHERLIES DO NOT LOOK TO
FULLY STRENGTHEN AGAIN UNTIL EARLY NEXT WEEK. HURRICANE MARIE WILL
DELIVER A LONG PERIOD SOUTHERLY SWELL SATURDAY. THOUGH SMALL, AT
AROUND 4 FT AT 16 SECONDS, THIS SWELL IS A LARGER THAN TYPICAL SWELL
FROM THIS DIRECTION AT THIS TIME OF YEAR.
BEACH HAZARDS...HURRICANE MARIE WILL USHER IN A LONG PERIOD
SOUTHERLY SWELL OF 3-4 FEET AT 16 SECONDS FOR SOUTH FACING BEACHES
BY SATURDAY INTO SUNDAY. THUS, THERE COULD BE A RISK OF SNEAKER
WAVES, ESPECIALLY IF THE SWELL COMES IN SLIGHTLY LARGER.
SNEAKER WAVES ARE A UNIQUE HAZARD, WITH UP TO 30 MINUTES BETWEEN
WAVES. LARGE, UNEXPECTED WAVES CAN SWEEP ACROSS THE BEACH WITHOUT
WARNING, SWEEPING PEOPLE INTO THE SEA FROM ROCKS, JETTIES, AND
BEACHES. THESE SNEAKER WAVES CAN ALSO MOVE LARGE OBJECTS SUCH AS
LOGS, CRUSHING ANYONE CAUGHT UNDERNEATH. EVEN ANKLE TO KNEE DEEP
WATER CAN KNOCK YOU DOWN AND DRAG YOU OUT WHEN A SNEAKER WAVE HITS.
PAY ATTENTION AND STAY ABOVE THE HIGH WATER LINE AND ANY WET SAND TO
STAY SAFE. IF THE GROUND IS WET, WAVES HAVE SURGED THERE RECENTLY.
STAY SAFE AND NEVER TURN YOUR BACK ON THE OCEAN!
EKA WATCHES/WARNINGS/ADVISORIES
CA...
BEACH HAZARDS STATEMENT THROUGH MONDAY EVENING FOR CAZ104-
109.
NORTHWEST CALIFORNIA COASTAL WATERS...
NONE.
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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