633
FXUS66 KEKA 122100
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
200 PM PDT MON OCT 12 2026
KEY MESSAGES
* ANOTHER COLD MORNING IS EXPECTED TUESDAY WITH AREAS OF FROST AND
FREEZING POTENTIAL.
* DRY CONDITIONS WILL LEAD TO AREAS OF LOW RELATIVE HUMIDITIES
THROUGH THE WEEK.
* A WARMING TREND IS EXPECTED TO IMPACT THE AREA THROUGH THE WEEK
INTO THE WEEKEND, PEAKING ON FRIDAY.
SYNOPSIS
CLEAR SKIES AND SEASONABLE TEMPERATURES ARE EXPECTED
TODAY. ANOTHER CHILLY MORNING IS FORECAST FOR TUESDAY MORNING WITH
AREAS OF FROST AND FREEZING POTENTIAL. A WARMING TREND WILL
INCREASE TEMPERATURES THROUGH THE WEEK.
DISCUSSION
LAST WEEKEND, A COLD FRONT BROUGHT COOLER AND DRY
AIR TO THE AREA. THIS SYSTEM DISRUPTED THE MARINE LAYER ALLOWING
FOR CLEAR SKIES AT THE COAST THROUGH EARLY THIS WEEK AS STEADY
LIGHT OFFSHORE WINDS OVERNIGHT CONTINUE. CLEAR SKIES AND LIGHT
WIND WILL ALLOW FOR UNINTERRUPTED COOLING IN THE VALLEY FLOORS.
FROST ADVISORIES AND FREEZE WARNINGS HAVE ALREADY BEEN ISSUED FOR
MANY INTERIOR VALLEYS FROM 1 A.M. THROUGH 8 A.M. TUESDAY MORNING.
WEDNESDAY NIGHT SHOULD BE WARM ENOUGH TO HAVE MUCH LESS IMPACTS
FROM COOLER TEMPERATURES AS TEMPERATURES COULD STRUGGLE TO REACH
OR GO BELOW 32F.
THROUGH THE WEEK, A SLIGHT WARMING TREND WILL TAKE EFFECT DUE TO
A BUILDING UPPER LEVEL RIDGE. THIS WEATHER PATTERN WILL RESULT IN
CALM, CHILLY CONDITIONS WITH BUILDING WINDS IN THE AFTERNOON AS
DAYTIME HEATING TAKES EFFECT. INLAND HEATING IS LIKELY TO PEAK
THURSDAY AND FRIDAY WITH VALLEYS REACHING THE HIGH 80S TO LOW 90S
AGAIN. WINDS WILL BE MOSTLY TERRAIN DRIVEN WITH UPSLOPE - UPVALLEY
FLOW. RELATIVE HUMIDITIES WILL REACH A MINIMUM LATE WEEK WITH
WIDESPREAD AREAS OF RH VALUES <20%. HOWEVER, WINDS WARE LIKELY TO
REMAIN TERRAIN-DRIVEN AND LIGHT TO MODERATE LATE WEEK.
THIS COMING SUNDAY INTO NEXT MONDAY, ENSEMBLE CLUSTERS SHOW AN
UPPER LEVEL TROUGH AND AN ASSOCIATED COLD FRONT ENTERING THE
AREA. BOTH THE GEFS AND EPS SUPPORT THIS AS WELL. THIS SYSTEM IS
7DAYS OUT AND COULD CHANGE SUBSTANTIALLY THROUGH THE WEEK. MOST
OF THIS SYSTEM'S RAIN WOULD FALL IN THE NORTHERN COUNTIES OF DEL
NORTE, HUMBOLDT, AND TRINITY WHERE SOME OF THE HIGHEST RIDGES
ABOVE 4000FT COULD SEE VERY LIGHT SNOW WHEREAS MENDOCINO AND LAKE
COUNTIES ARE MORE LIKELY TO SEE MODERATE TO STRONG NW WINDS IF
THIS SYSTEM REMAINS ON TRACK. THIS SYSTEM IS CAPABLE OF CHANGING
AND UPDATES CAN BE EXPECTED THROUGH THE WEEK. DS
AVIATION...18Z UPDATE
VFR CONDITIONS ARE EXPECTED TO BE
WIDESPREAD TODAY FOR ALL TERMINALS IN NW CA. GUSTY NORTHERLY WINDS
ARE EXPECTED AT COASTAL TERMINALS AND WITHIN RIVER VALLEYS NEAR
THE COAST. INLAND TERMINALS CAN EXPECT TERRAIN-DRIVEN
UPSLOPE/UPVALLEY WINDS, YET GUSTS ARE NOT EXPECTED TO BE
WIDESPREAD. WINDS WILL CALM NEAR SUNSET WITH CONTINUED VFR
CEILINGS THROUGH THE NIGHT. VERY SHALLOW GROUND FOG IS POSSIBLE,
YET MINIMAL IMPACTS ARE EXPECTED AT THIS TIME. DS
MARINE
GALE FORCE WINDS HAVE DECREASED THROUGH THE MORNING
LEADING TO WAVE HEIGHTS DECREASING SOONER THAN EXPECTED.
WIDESPREAD SMALL CRAFT ADVISORIES REMAIN AS WAVES CONTINUE TO BE
STEEP. A FAIRLY SIZABLE NW SWELL HAS ALSO ENTERED THE WATERS
WHICH IS CURRENTLY BEING RECORDED AT 7FT @ 17S. MODERATE TO FRESH
BREEZES ARE LIKELY TO DEVELOP LEADING TO A CONTINUED LOWERING OF
SHORT PERIOD SEAS AND THE OVERALL SEA STATE. THIS NW SWELL IS
LIKELY TO WANE TO 4-5FT AND MIX WITH A S SWELL OF 3-4FT THROUGH
THE WEEK. DS
FIRE WEATHER
MULTIPLE DAYS OF COOL BUT DRY AIR HAS LOWERED ERC
VALUES. MUCH WEAKER, TERRAIN-DRIVEN WINDS AND AN INCREASINGLY
STABLE ATMOSPHERE IN THE COMING DAYS WILL HELP GREATLY REDUCE
OVERALL FIRE DANGER. HOWEVER, DRY CONDITIONS ARE EXPECTED THROUGH
THE WEEK (AROUND 20% RH EACH DAY) WITH WORSENING OVERNIGHT
RECOVERIES THROUGH THURSDAY AS MIDSLOPE THERMAL BELTS DEVELOP.
SMOKE TRANSPORT WILL ALSO WORSEN THROUGH THE WEEK FOR ANY FIRES
THAT DO START. MORE MOIST AIR IS EXPECTED TO PUSH ACROSS THE AREA
THIS WEEKEND WITH A POTENTIAL FOR VERY BREEZY CONDITIONS IN
MENDOCINO AND LAKE COUNTY LATE THIS WEEKEND INTO EARLY NEXT WEEK.
DS
BEACH HAZARDS
A LONG PERIOD SWELL CURRENTLY UP TO ABOUT 7 FEET
AT 17 SECONDS WILL PERSIST THROUGH THE DAY MONDAY. AS SHORT
PERIOD SEAS BEGIN TO FALL, THIS SWELL WILL PROVIDE AND INCREASING
SNEAKER WAVE RISK THROUGH THE DAY. THE SWELL WILL BEGIN TO DECAY
TUESDAY. THE SNEAKER WAVE RISK WILL LESSEN AS THE SWELL DECAYS,
BUT WILL REMAIN THROUGH MIDWEEK ESPECIALLY AS SHORT PERIOD SEAS
CALM.
THE HIGHEST RISK IS EXPECTED DURING PERIODS OF INCOMING TIDES. WITH
HIGH TIDES ALONG THE CALIFORNIA COAST AT AROUND 11AM TO 1PM. A
POSITIVE TIDAL ANOMALY IS YIELDING TIDES AROUND 1-1.2 FEET HIGHER
THAN PREDICTIONS ON TOP OF HIGHER THAN USUAL TIDES, ADDING TO THE
THREAT. /JHW
EKA WATCHES/WARNINGS/ADVISORIES
CA...
BEACH HAZARDS STATEMENT UNTIL 10 PM PDT THIS EVENING FOR
CAZ101-103-104-109.
FROST ADVISORY FROM 1 AM TO 8 AM PDT TUESDAY FOR CAZ103-104-
106-108>111-114-116>118.
FREEZE WARNING FROM 1 AM TO 8 AM PDT TUESDAY FOR CAZ108-110-
111-114-116-117.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 3 AM PDT TUESDAY FOR PZZ450-455.
SMALL CRAFT ADVISORY UNTIL NOON PDT TUESDAY 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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