507
FXUS66 KEKA 032130
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
230 PM PDT FRI OCT 3 2025
SYNOPSIS
DRY WEATHER AND LOCALLY GUSTY WINDS ARE EXPECTED
THROUGH EARLY NEXT WEEK. COOL MORNINGS AND WARMER DAYTIME HIGHS
ARE EXPECTED FOR THE INTERIOR VALLEYS THROUGH EARLY NEXT WEEK.
ANOMALOUS WARMTH WILL BE POSSIBLE FOR THE NORTH COAST ON MONDAY.
DISCUSSION
DRY WEATHER AND LOCALLY GUSTY WINDS ARE ANTICIPATED
THROUGH THE WEEKEND. STRONGEST NORTHERLIES THIS AFTERNOON/TONIGHT
WILL MOST LIKELY BE OVER THE COASTAL HIGH TERRAIN OF SW HUMBOLDT/NW
MENDO AND OVER PORTIONS OF THE MENDO COAST AS A LOW LEVEL NORTHERLY
SPEED MAX DEVELOPS IN LEE OF CAPE MENDO. A FRONT WILL APPROACH FROM
THE NW ON SATURDAY AND IS FORECAST TO DISSIPATE BEFORE REACHING
THE NORTH COAST. GUSTIER HIGHER TERRAIN NORTHERLIES ARE FORECAST
TO RETURN ON SATURDAY AND PREVAIL INTO SUNDAY AS AN INVERTED TROUGH
DEVELOPS ALONG OR NEAR THE COAST. WINDS OVERALL FOR MOST LAND SITES
WILL NOT BE VERY STRONG, HOWEVER LOCALLY STRONG AND GUSTY E-NE WINDS
ARE FORECAST TO RAMP UP SUNDAY NIGHT OVER HIGH TERRAIN AND RIDGES.
GRADUAL DRYING IS EXPECTED FOR THE INTERIOR VALLEYS AFTER MULTIPLE
DAYS OF RAIN. THERE IS A POSSIBILITY FOR LOCALIZED FROST FOR THE
COLDER INTERIOR VALLEYS, ABOUT 30-40% CHANCE IN TRINITY COUNTY AT
PLACES LIKE RUTH AND HAYFORK. CHANCES ARE LESS FOR NORTHERN
MENDOCINO AND NORTHERN LAKE, 10-20%. LARABEE VALLEY NEAR DINSMORE
HAS THE HIGHEST CHANCE, ABOUT 60-70% CHANCE. FOG AND LOW CLOUDS
WILL MOST LIKELY FORM ACROSS THE INTERIOR VALLEYS TONIGHT AND
COUNTERACT THE LONGWAVE COOLING. DRYING OFFSHORE FLOW SUNDAY INTO
MONDAY MAY YIELD BETTER CHANCES FOR EARLY MORNING FROST AS SKIES
REMAIN CLEARER LONGER. THE AIR MASS DOES WARM UP CONSIDERABLY OVER
THE WEEKEND INTO EARLY NEXT WEEK WITH INTERIOR VALLEY HIGH TEMPERATURES
WELL ABOVE NORMAL (LOWER TO MID 80S SUNDAY AND MONDAY). LATEST
INDICATIONS ARE FOR STRONGER OFFSHORE FLOW AND INCREASED POTENTIAL
FOR ANOMALOUS NORTH COAST WARMTH WITH HIGH IN THE LOWER TO MID
70S ON MONDAY.
GREATER FORECAST UNCERTAINTY CROPS UP ON MONDAY IF A SOUTHERLY
WIND REVERSAL DEVELOPS ALONG THE MENDOCINO COAST. THIS SOUTHERLY
WIND REVERSAL MAY RESULT IN COASTAL STRATUS AND FOG FOR THE MENDO
COAST AND SW HUMBOLDT COAST. WITH WARMER AIR MASS AND WEAK
ONSHORE FLOW. SHALLOW MARINE LAYER STRATUS AND FOG MAY BEGIN
TO RETURN TO THE NORTH COAST BY TUE AND WED.
NOT MUCH CHANCE FOR RAIN EVEN INTO MID NEXT WEEK AS WEAK FRONT
PASSES INTO THE PAC NW. THERE ARE SIGNS FOR MORE WET WEATHER LATE
IN THE WEEK AS ANOTHER SURFACE LOW AND FRONTAL SYSTEM APPROACHES
THE NORTHERN CALIFORNIA COAST. ENSEMBLE 500MB MEANS AND ANOMALIES
FROM THE VARIOUS GLOBAL MODELS (ECMWF ENS, GEFS AND CMCE) INDICATE
CONSIDERABLE VARIABILITY WITH THE TIME EVOLUTION, PLACEMENT AND
DEPTH OF THE 500MB COLD CORE. MOST ALL WPC 500MB CLUSTERS SHOW
THIS TROUGH RIGHT OFFSHORE BY DAY 5 (THU), TRAVERSING SOMEWHERE
ACROSS OR NEARBY THE WEST COAST DAYS 6 TO 7 (FRI-SAT). IT IS
POSSIBLE (10-20%) FOR ANOTHER 1" OF RAIN OVER 24 HOURS FOR NW
CALIFORNIA MOUNTAINS BY LATE FRI. STAY TUNED AS NEXT WEEKEND MAY
BE WET AND UNSETTLED IF THIS TROUGH/COLD CORE LOW COMPLEX TAKES
LONGER TO ADVANCE ACROSS THE FORECAST AREA.
AVIATION...(18Z TAFS)
CLOUDS CONTINUE TO DISSIPATE FOR TERMINALS
AROUND NORTHWEST CALIFORNIA AS A FRONT CONTINUES EAST. BEHIND THE
FRONT, NORTH TO NORTHWESTERLY WINDS ALONG THE NORTH COAST WILL
CONTINUE TO INCREASE THIS AFTERNOON AND MOST LIKELY TOMORROW
AFTERNOON, AS WELL. THE HIGHEST GUSTS FOR THIS AFTERNOON AND EVENING
ARE FORECAST TO BE AROUND POINT ST. GEORGE IN DEL NORTE COUNTY AND
ALONG THE MENDOCINO COAST WITH MODELS SHOWING AN 80 TO 90 PERCENT
CHANCE FOR GUSTS GREATER THAN 25 KNOTS. WHILE NORTH TO NORTHWESTERLY
WINDS ARE EXPECTED TO INCREASE ALONG THE COAST FROM THE DEL
NORTE/HUMBOLDT COUNTY BORDER TO CAPE MENDOCINO, GUSTS ARE NOT
ANTICIPATED TO BE AS HIGH.
COASTAL STRATUS, ALONG WITH GENERAL CLOUDINESS, IS NOT EXPECTED TO
BE WIDESPREAD DUE TO GENERAL OFFSHORE FLOW, ESPECIALLY OVER DEL
NORTE COUNTY. PERIODS OF MVFR TO IFR CEILINGS COULD OCCUR ALONG THE
HUMBOLDT COAST NORTH OF CAPE MENDOCINO THIS EVENING AND INTO EARLY
SATURDAY, ESPECIALLY AROUND HUMBOLDT BAY. KUKI IS EXPECTED TO REMAIN
VFR THROUGH THIS CURRENT TAF PERIOD WITH GENERAL NORTHERLY WINDS
EXPECTED TO PICK UP THIS AFTERNOON. /JLW
MARINE
COMBINED SEAS HAVE DIPPED BELOW 10 FT ACROSS THE WATERS.
NORTHERLIES CONTINUE TO FILL BACK IN AND STRENGTHEN TODAY WITH
GUSTS PEAKING AROUND 20-25 KTS THIS AFTERNOON IN THE OUTER WATERS
AND NEARSHORE MENDOCINO. WINDS NUDGE FURTHER UPWARD SATURDAY,
BRINGING LOCALIZED GALE FORCE GUSTS IN THE WATERS IN THE LEE OF
CAPE MENDOCINO. PEAK GUSTS ELSEWHERE RANGE FROM 20-30 KTS.
GALE POTENTIAL EXPANDS LATE SATURDAY INTO SUNDAY WITH NBM SHOWING A
24 HOUR PROBABILITY OF 80 TO 90% FOR GALES IN THE SOUTHERN WATERS.
CHANCES ARE LESS CERTAIN FOR GALE CONDITIONS FOR THE NORTHERN OUTER
WATERS. SHORT PERIOD SEAS WILL DOMINATE THE SEA STATE, WITH STEEP
WAVES OF UP TO 7-9 FT CURRENTLY FORECAST BY THE WEEKEND. THESE WILL
LIKELY PROPAGATE INTO THE INNER WATERS, EVEN AS WINDS REMAIN
LIGHTER. HIGH PRESSURE WEAKENS BY LATE SUNDAY INTO EARLY NEXT WEEK,
AND WINDS ARE LIKELY TO EASE. JB
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 11 PM PDT SATURDAY FOR PZZ455.
SMALL CRAFT ADVISORY FROM 11 AM TO 11 PM PDT SATURDAY FOR
PZZ470.
GALE WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR
PZZ470.
SMALL CRAFT ADVISORY UNTIL 3 PM PDT SATURDAY FOR PZZ475.
GALE WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY MORNING
FOR PZZ475.
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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