563
FXUS66 KEKA 180850
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
1250 AM PST SUN JAN 18 2026
SYNOPSIS
HIGH PRESSURE IS FORECAST TO REMAIN OVER NW CALIFORNIA
INTO THE NEW WEEK RESULTING IN DRY WEATHER AND GENERALLY ABOVE
NORMAL DAYTIME TEMPERATURES. OVERNIGHT AND MORNING TEMPERATURES
WILL REMAIN CHILLY WITH NIGHT AND SHALLOW MORNING FOG IN THE RIVER
VALLEYS.
DISCUSSION
AN UPPER LEVEL RIDGE HAS SITUATED ITSELF OVER THE WEST
COAST LEADING TO LARGE SCALE SUBSIDENCE AND ADIABATIC WARMING.
ANOMALOUS INTERIOR WARMTH WITH TEMPERATURES ABOVE CLIMATOLOGICAL
NORMS WILL CONTINUE UNDER THE STRONG RIDGE. WITH CLEAR SKIES AND
EXCEPTIONAL LONGWAVE COOLING, IT WILL CONTINUE TO REMAIN COLD IN
THE RIVER VALLEYS EACH NIGHT AND MORNING, ESPECIALLY IN NORTHERN
HUMBOLDT, TRINITY AND NORTHERN MENDO. THE RIDGE ALOFT WILL
CONTINUE TO PROVIDE DRY AND STABLE WEATHER CONDITIONS FOR NW
CALIFORNIA INTO THE NEW WEEK. THE ANOMALOUS INTERIOR JANUARY
WARMTH IS CONTRIBUTING TO A STRONG INVERTED TROUGH.
HIGH CLOUDS WILL STREAM OVER THE AREA WITH COASTAL STRATUS
SETTLING ALONG THE COAST THIS MORNING. PATCHY DENSE FOG CAN BE
EXPECTED THIS MORNING, ESPECIALLY AROUND HUMBOLDT BAY AND
INTERIOR RIVER VALLEYS. WINDS WILL REMAIN LIGHT THIS MORNING WITH
SOME LIGHT OFFSHORE FLOW, WHICH MAY HELP TO LIFT STRATUS ALONG THE
COAST. THE TREND IN WIND BEARING ALOFT MAY REINFORCE CLOUD COVER
DESPITE SURFACE WINDS TRENDING EASTERLY.
THE RESILIENT RIDGE REMAINS OVER THE PACNW, AND WILL CONTINUE ITS
REGIME OF SUBSIDENCE, HELPING TO SCATTER OUT CLOUD COVER OVER THE
CWA BY THIS AFTERNOON. CHANCES FOR THE RIDGE TO WEAKEN OR
BREAKDOWN DO NOT INCREASE UNTIL THE MIDDLE OF THIS COMING WEEK.
PROBABILITIES FOR MEANINGFUL RAINFALL OVER 0.1 INCH DO NOT
INCREASE UNTIL LATE THIS COMING WEEK AND NEXT WEEKEND. AFTER
ANOTHER PROLONGED STRETCH OF DRY WEATHER, WET WEATHER WILL LIKELY
RETURN FOR THE LATTER PART OF JANUARY FOR NW CA.
AVIATION
THE MARINE LAYER HAS MOVED IN AND IS BRINGING LIFR
CONDITIONS TO THE COASTAL AREAS. THE HREF SHOWS THIS PUSHING BACK TO
THE COAST SOMETIME AROUND MID TO LATE MORNING AND THEN QUICKLY
RETURNING IN THE EVENING. THE INLAND VALLEYS ARE SEEING FOG RETURN
AGAIN TONIGHT AND THIS WILL CLEAR OUT DURING THE DAY ON SUNDAY.
UKIAH IS NOT EXPECTED TO SEE FOG, BUT WITH THE PATTERN SHIFT AND
MORE STRATUS AROUND THIS WILL NEED TO BE WATCHED. MKK
MARINE
NORTHERLY WINDS REMAIN AROUND 5 TO 15 KT SOUTH OF CAPE
MENDOCINO AND THESE MAY INCREASE SLIGHTLY THIS AFTERNOON WITH AREAS
OF 20 KT WINDS SOUTH OF CAPE MENDOCINO. THIS WILL GENERALLY BRING
WIND DRIVEN WAVES OF 3 TO 5 FEET. LOCALLY AREAS OF 6 FOOT WAVES ARE
POSSIBLE JUST DOWNWIND OF CAPE MENDOCINO. NORTH OF CAPE MENDOCINO
NORTHERLY WINDS ARE EXPECTED TO INCREASE TO AROUND 10 KT TONIGHT.
THESE CONDITIONS ARE EXPECTED TO PERSIST THROUGH MONDAY EVENING AND
DIMINISH MONDAY NIGHT.
MONDAY NIGHT AND TUESDAY THE GFS WAVE MODEL IS SHOWING A LONG PERIOD
WEST TO NORTHWEST WAVE MOVING IN AND BUILDING TO AROUND 5 TO 6 FEET
AT 16 SECONDS. THIS IS EXPECTED TO COMBINE WITH A 3 OR 4 FOOT WAVE
OF 12 SECONDS.
LIGHTER WINDS ARE EXPECTED TUESDAY AND WEDNESDAY BEFORE STRONG TO
NEAR GALE FORCE WINDS ARE EXPECTED TO RETURN LATE IN THE WEEK. MKK
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
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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