110
FXUS66 KEKA 140706
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
1206 AM PDT MON SEP 14 2026
KEY MESSAGES
* HIGH PRESSURE OFFSHORE BUILDS THROUGH MONDAY, INCREASING NORTHERLY
WINDS.
* HIGH PRESSURE IS EXPECTED TO BRING WARMER TEMPERATURES AND DRY
WEATHER MONDAY AND TUESDAY.
* COOLER TEMPERATURES AND A 5 TO 10 PERCENT CHANCE OF THUNDERSTORMS
IN TRINITY COUNTY ARE EXPECTED WEDNESDAY AFTERNOON AND OVERNIGHT.
SYNOPSIS
SURFACE HIGH PRESSURE BUILDING OFFSHORE WILL
STRENGTHEN THE ONSHORE PRESSURE GRADIENT AGAINST THE INTERIOR
THERMAL LOW INTO EARLY THIS WEEK. EXPECT A SHALLOW MARINE LAYER
PINNED ALONG THE COAST WHILE THE INTERIOR VALLEYS HAVE DRY,
SEASONABLY WARM. CONDITIONS. FOR WEDNESDAY, AN EVOLVING UPPER LOW
WILL BRING COOLER TEMPERATURES AND SLIGHT CHANCE FOR INTERIOR
THUNDERSTORMS.
DISCUSSION
AN UPPER LEVEL TROUGH IS MOVING OUT OF THE AREA EARLY
THIS MORNING AS WEAK UPPER LEVEL RIDGING SLIGHTLY BEGINS TO DOMINATE
THE WEATHER PATTERN FOR THE EARLY WEEK. CLEAR SKIES LATE NIGHT WILL
HAVE THE POTENTIAL TO FOG OVER FOR SOME INLAND VALLEYS BY DAWN IF
TEMPERATURES GET LOW ENOUGH. NO WIDESPREAD FROST IS EXPECTED FOR THE
INTERIOR DUE TO THE INCREASED POTENTIAL FOR FOG. MONDAY AND TUESDAY
TEMPERATURES WARM UP AGAIN IN THE INLAND AREAS. AFTER TODAY'S HIGHS
IN THE 70S INLAND TEMPERATURES ARE EXPECTED TO WARM BY 10 DEGREES IN
MANY AREAS WITH HIGHS IN THE MID 80S TO LOW 90S MONDAY AND SLIGHTLY
WARMER ON TUESDAY. COASTAL AREAS ARE LIKELY TO SEE A CLEAR, YET
BREEZY AFTERNOON WHICH WILL KEEP TEMPERATURES RELATIVELY TAME IN THE
MID TO UPPER 60S.
MIDWEEK, A CHANGE IN THE WEATHER PATTERN IS EXPECTED. AN UPPER LEVEL
TROUGH IS PREDICTED TO FORM NEAR BRITISH COLUMBIA BEFORE ENDING UP
OVER NW CA. THIS SYNOPTIC FEATURE HAS YET TO BE FORMED, LEADING TO A
FAIRLY HIGH DEGREE OF FORECAST UNCERTAINTY AT THE MOMENT. ONCE THE
TROUGH THAT HAS BEEN OVER THE AREA FROM THE WEEKEND MOVES EASTWARD,
THIS FEATURE IS LIKELY TO FORM AND FORECAST CERTAINTY SHOULD
INCREASE MUCH MORE FROM THERE ON OUT.
THAT SAID, THIS PREDICTED FEATURE AND ITS RESULTING PATTERN WILL
LIKELY BE TOO DRY AND WEAK TO PRODUCE MEANINGFUL RAIN. HOWEVER, A
FEW CONVECTIVE SHOWERS ARE POSSIBLE IN THE EVENING, ESPECIALLY FOR
THE SALMON AND KLAMATH MOUNTAINS. THERE IS SOME INSTABILITY ALREADY
MODELED INCREASING THE POTENTIAL FOR A THUNDERSTORM IF THE MOISTURE
IS AMPLE ENOUGH. BESIDES THE FAINT STORM POTENTIAL, THIS SYSTEM WILL
KEEP TEMPERATURES SLIGHTLY BELOW NORMAL FOR MOST OF THE FORECAST
AREA. END OF THE COMING WEEK LOOKS LIKE WARMER TEMPS RETURN AS THIS
UPPER TROUGH EXITS THE AREA.
AVIATION
NORTHERLY WINDS FOR EXPOSED TERRAIN AND CALM WINDS
ELSEWHERE WITH VFR IS EXPECTED FOR ALL AREAS TONIGHT AS SLIGHT
OFFSHORE WINDS CONTINUE TO FLOW. OVERCAST CONDITIONS ARE BEING SEEN
DEVELOPING NEAR FOT, YET THIS IS NOT EXPECTED TO MAKE IT ACV OR CEC.
IF THIS LEVEL DOES FORM, NORTHERLIES WILL MIX THIS LAYER OUT EARLY,
YET ANY COVERAGE HAS BEEN DISCONTINUED FROM THE TAFS DUE TO
DECREASING CONFIDENCE. INLAND AREAS CAN EXPECT TERRAIN INFLUENCED
WIND WITH VFR THROUGH THE FIRST HALF OF THE WEEK.
MARINE
HIGH PRESSURE CONTINUES TO BUILD INTO THE AREA. AS A
RESULT, WINDS WILL SHIFT TO THE NORTHWEST AND THEN MORE NORTHERLY
THROUGH THE OVERNIGHT HOURS INTO MONDAY MORNING. THESE ARE EXPECTED
TO INCREASE TO AROUND 25 TO 30 BY MONDAY AFTERNOON WITH THE STRONGER
WINDS IN THE SOUTHERN WATERS AND FAR NORTHERN OUTER WATERS. A FEW
GALE FORCE GUSTS ARE POSSIBLE IN LOCALIZED AREAS IN THE LEE OF THE
CAPES, YET AT THIS POINT THEY ARE NOT EXPECTED TO BE WIDESPREAD
ENOUGH TO WARRANT A GALE WARNING. THE WINDS DO MAKE THEIR WAY INTO
THE SOUTHERN INNER WATERS MONDAY AFTERNOON, AND WILL LIKELY PUSH
FARTHER OFFSHORE MONDAY NIGHT. THE NORTHERN INNER WATERS ARE NOT
EXPECTED TO SEE WIDESPREAD WINDS OVER 20 KT TO WARRANT A SMALL CRAFT
ADVISORY, BUT THE STEEP SHORT PERIOD SEAS COULD EXCEED 6 FEET AND
THIS MAY REQUIRE A SMALL CRAFT ADVISORY.
FOR WEDNESDAY, WINDS AND SEAS ARE EXPECTED TO RAPIDLY DIMINISH IN
THE EVENING AND OVERNIGHT, BUT THIS MAY STILL CHANGE SLIGHTLY. A
SMALL UPPER LEVEL TROUGH IS DROPPING SOUTH OVER THE AREA AND A SMALL
SHIFT IN THE STORM TRACK COULD CHANGE THE WINDS SUBSTANTIALLY.
THURSDAY AND FRIDAY, FAIRLY LIGHT SOUTHERLY WINDS ARE EXPECTED
BEFORE NORTHERLY WINDS RETURN AND START TO INCREASE FOR THE WEEKEND.
MKK
FIRE WEATHER
HIGH PRESSURE BUILDING OFF THE COAST WILL BRING A
WARMING AND DRYING TREND ACROSS NORTHWEST CALIFORNIA THROUGH
TUESDAY. BREEZY NORTH TO NORTHWEST WINDS WILL DEVELOP ACROSS THE
RIDGES AND EXPOSED INTERIOR VALLEYS THIS AFTERNOON AND MONDAY
AFTERNOON WITH LOCAL GUSTS BETWEEN 15 AND 25 MILES PER HOUR.
LOCALLY STRONGER WINDS AND LOWER RH RECOVERY ARE EXPECTED IN EASTERN
LAKE COUNTY EARLY MONDAY. WEDNESDAY AFTERNOON OR OVERNIGHT AN UPPER
LOW HAS THE POTENTIAL TO BRING A FEW THUNDERSTORMS TO TRINITY
COUNTY.
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY FROM NOON TODAY TO 3 AM PDT TUESDAY
FOR PZZ455.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT WEDNESDAY FOR PZZ470.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT WEDNESDAY 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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