702
FXUS66 KEKA 142356
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
456 PM PDT FRI AUG 14 2026
AVIATION
00Z TAFS. A SHORTWAVE TROUGH WILL IMPACT THE REGION
THROUGH SATURDAY MORNING CAUSING THE MARINE LAYER TO DEEPENED WITH
LIGHT WINDS ALONG THE COAST. AFTERNOON AND EVENING MVFR TO IFR
CEILINGS AT THE COASTAL TERMINALS WILL TRANSITION TO IFR TO LIFR
THROUGH SATURDAY MORNING. LIGHT COASTAL DRIZZLE WOULD FURTHER
LOWER VIS AND BRING CHANCES FOR FOG. CEILINGS WILL LIFT SATURDAY,
BUT THE DEEP MARINE LAYER WILL LIKELY LACK COVERAGE IN AGAIN TO
LIMIT CLEARING ALONG THE COAST. INLAND, EXPECT GUSTY AFTERNOON
WINDS AND INCREASED LOW LEVEL COULD COVERAGE, ESPECIALLY WITHIN
COASTAL RIVER VALLEYS. THE RUSSIAN RIVER VALLEY IS EXPECTED TO
HAVE OVC CEILINGS AT UKI WITH LATE MORNING CLEARING IN THE 17-18Z
SATURDAY PERIOD.
PREV DISCUSSION
/ISSUED 326 PM PDT FRI AUG 14 2026/
KEY MESSAGES...
* SLIGHT CHANCE OF INTERIOR THUNDERSTORMS TODAY INTO SATURDAY.
* SMOKEY CONDITIONS LIKELY FROM THE MP18 FIRE, FOCUSED IN THE
TRINITY RIVER VALLEY AND TRINITY COUNTY.
* COOLER TEMPERATURES ARE LIKELY THROUGH NEXT WEEK.
SYNOPSIS...A TROUGHING PATTERN HAS SET UP OVER THE REGION. INLAND
AREAS CAN EXPECT COOLER TEMPERATURES WITH THE COAST CONTINUING TO
HAVE OVERCAST CONDITIONS AND BRIEF AFTERNOON CLEARING. PASSING
SHORTWAVE DISTURBANCES INCREASE THE CHANCE FOR STORMS INLAND.
DISCUSSION...THE APPROACH OF AN UPPER LEVEL TROUGH HAS AND WILL
HAVE DYNAMIC EFFECTS ON SHORT TERM WEATHER THROUGH THE WEEKEND.
THE EXTENT OF WHAT THOSE EFFECTS ARE IS STILL UNCERTAIN AS THE
AXIS OF THE BROADER OPEN WAVE SYSTEM SWINGS OVER THE CWA. FROM
MODEL SOUNDINGS THERE ARE A FEW MOISTURE SIGNATURES AT 7K FEET
AND WAY UP HIGH IN THE 33K FEET RANGE OR 300MB WHICH CONFIRMS THE
HIGH CLOUDS SEEN IN THE IR SATELLITE OBSERVATION YOU CAN SEE
THERE. THE LIGHTNING DETECTION NETWORK HAS NOT SHOWN ANY CLOUD TO
CLOUD OR CLOUD TO GROUND STRIKES AS OF 21Z WHICH COULD MEAN WEAK
UPDRAFT HELICITY. MOST OF THE COMPONENTS THAT WOULD GIVE US
CONFIDENCE IN WARNING OF A HIGHLY PROBABLE-DANGEROUS SYSTEM JUST
ARE'NT THERE BUT AT LEAST WITHIN A 10-15% CHANCE OF LIGHTNING THIS
LATE AFTERNOON AND INTO THE EVENING. AREAS THAT ARE BEING
HIGHLIGHTED FOR HREF LIGHTNING PROBABILITIES > 10% INCLUDE
TRINITY COUNTY NEAR HAYFORK AND ALONG THE YOLLA BOLLY DISTRICT-
NEIGHBORING TEHAMA AND GLENN COUNTIES. OF PARTICULAR FOCUS WOULD
ALSO BE THE BORDER OF SISKIYOU WITH TRINITY AND DEL NORTE, WHICH
SKEW-T SOUNDINGS SHOW CAPE VALUES IN THE 740 J/KG RANGE WITH
SIMILAR LIGHTNING PROBABILITIES > 10%. IF ANY CONVECTIVE ACTIVITY
STARTS, IT WILL BE OVER BY 06-07Z. OTHER FEATURES FROM THE
TROUGHING PATTERN WILL BE COOLER TEMPERATURES AND THE INCREASED
CHANCE FOR RAINSHOWERS AND THUNDERSTORMS FOR THE INTERIOR. WHILE
MOISTURE FLOW IS NOT TOO IMPRESSIVE, THESE SHORTWAVE DISTURBANCES
COULD HAVE ENOUGH OF AN IMPACT TO PROMOTE CONVECTIVE ACTIVITY
THROUGH SATURDAY. GLOBAL ENSEMBLES SHOW THIS SYNOPTIC FEATURE
CONTINUING THROUGH NEXT WORK WEEK. EXPECT RELATIVELY REPETITIVE
WEATHER CONDITIONS FOR THE NEXT SEVERAL DAYS. /EYS
AVIATION...18Z TAFS. A SHORTWAVE TROUGH IS MOVING THROUGH THE
REGION THROUGH SATURDAY MORNING. THE MARINE LAYER HAS FURTHER
DEEPENED WITH LIGHT WINDS IN RESPONSE. AFTERNOON AND EVENING MVFR TO
IFR CEILINGS AT THE COASTAL TERMINALS WILL TRANSITION TO IFR TO LIFR
THROUGH SATURDAY MORNING. LIGHT COASTAL DRIZZLE WOULD FURTHER LOWER
VIS AND BRING CHANCES FOR FOG. CEILINGS WILL LIFT SATURDAY, BUT THE
DEEP MARINE LAYER WILL LIKELY LOCK COVERAGE IN AGAIN TO LIMIT
CLEARING ALONG THE COAST. FARTHER SOUTH, ABUNDANT STRATUS IN PLACE
THROUGH THE RUSSIAN RIVER VALLEY IS EXPECTED TO TRANSPORT BACK INTO
UKI BEFORE LATE MORNING CLEARING IN THE 17-18Z SATURDAY PERIOD.
MARINE...A RELATIVELY WEAK TROUGH HAS SET UP OVER THE REGION. THIS
HAS CAUSED A DECREASE IN OVERALL WIND SPEEDS. WAVES REMAIN STEEP,
YET THEY SHOULD CONTINUE TO DECAY THROUGH THE END OF THE WEEK. A
SOUTHERLY SWELL OF ~3FT WILL BUILD INTO THE REGION BY THE WEEKEND
AND WILL MIX WITH NORTHERLY SHORTER PERIOD WAVES. HOWEVER, THE
OVERALL SEA STATE SHOULD REMAIN MIXED WITH THESE TWO WAVE GROUPS
THROUGH THE START OF NEXT WEEK. LIGHT TO MODERATELY BREEZY (~20KT)
WINDS ARE EXPECTED THROUGH THE EXTENDED FORECAST AS OF RIGHT NOW.
FIRE WEATHER...A TROUGHING PATTERN HAS SET UP OVER THE REGION. THIS
WILL RESULT IN LOWER DAYTIME TEMPERATURES, INCREASED RH VALUES, AND
STRONGER WINDS DUE TO INCREASED MIXING. A DEEPER MARINE LAYER
WILL REACH FURTHER UP RIVER VALLEYS THROUGH THE NIGHT AS WELL,
POSSIBLY IMPACTING ANY RX BURNING OPERATIONS.
THIS EVENING, THERE IS A LOW CHANCE (10-15%) OF HIGHLY IMPACTFUL
THUNDERSTORMS FORMING OVER THE INTERIOR SPECIFICALLY FOR THE
KLAMATH, SALMON, AND YOLLA BOLLY MOUNTAINS. FORECAST CONFIDENCE IS
VERY LOW DUE TO DECREASED INSTABILITY AND RELATIVELY NORMAL
MOISTURE, HOWEVER LIFTING WILL BE AMPLIFIED DUE TO A SHORTWAVE
DISTURBANCE FLOWING OVER THE REGION. ANY STORMS THAT DO FORM WILL
HAVE MOTIONS TOWARDS THE NE WHICH SHOULD DECREASE THE CHANCE OF
ANY IMPACTS. HOWEVER, DCAPE VALUES REMAIN AMPLIFIED ENOUGH CREATE
GUSTS CAPABLE OF TRAVELING DOWN RIVER VALLEYS.
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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