095
FXUS66 KEKA 180701
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
1201 AM PDT THU JUN 18 2026
SYNOPSIS
TEMPERATURES WILL CONTINUE TO COOL THROUGH FRIDAY WITH
MARINE INFLUENCE DEEPENING AND PUSHING MORE INLAND. SCATTERED DRY
THUNDERSTORMS WILL IMPACT HIGH TERRAIN LOCATIONS OVER THE INTERIOR
FRIDAY.
KEY MESSAGES
- TEMPERATURES EASE THROUGH THE END OF THE WEEK WITH ONLY MINOR
HEATRISK
- VERY SLIGHT CHANCE OF DRY THUNDERSTORMS OVER HIGH TERRAIN THURSDAY
WITH GREATER CHANCES FRIDAY.
- A LIFTING BUT PERSISTENT MARINE LAYER AT THE COAST.
DISCUSSION
COOLING WILL CONTINUE THURSDAY AS A BROAD TROUGH
APPROACHES THE AREA. THE TROUGH WILL HELP GENERATE SOME UPPER LEVEL
CLOUDS AND PULL IN MORE MARINE INFLUENCE, HELPING TO DROP INTERIOR
HIGH TEMPERATURES INTO THE 80S. A DEEPENING MARINE LAYER IS
EXPECTED ALONG THE COAST THURSDAY MORNING.
THE TROUGH WILL ALSO AID IN INCREASING UPPER LEVEL INSTABILITY.
COMBINED WITH A MOISTURE SURGE UP THE SACRAMENTO VALLEY, THERE IS A
CHANCE (10%) OF ISOLATED, MOSTLY DRY THUNDERSTORMS OVER EASTERN
TRINITY THURSDAY EVENING. THUNDERSTORM POTENTIAL WILL INCREASE
FRIDAY WITH A 20% CHANCE OF ISOLATED DRY STORMS FRIDAY AFTERNOON
OVER NORTHERN HUMBOLDT AND TRINITY COUNTIES WITH A LESSER CHANCE
EXTENDING AS FAR SOUTH AS THE YOLLA BOLLYS. OTHERWISE, TEMPERATURES
WILL BOTTOM OUT FRIDAY WITH SLIGHT WARMING INTO THE WEEKEND.
SEASONABLY WARM AND DRY CONDITIONS ARE ANTICIPATED THIS WEEKEND,
WITH MOSTLY UNIMPACTFUL CONDITIONS. LONG RANGE MODELS INDICATE
POTENTIAL FOR A MODERATE HEATWAVE NEXT WEEK.
/JHW
AVIATION
AN UPPER LEVEL LOW WILL AFFECT AREA TERMINALS
THROUGH THE END OF THE WORK WEEK. EARLY THIS MORNING, MOST MODELS
INDICATE A COASTAL MARINE LAYER QUICKLY RESURGING TO CREATE LIFR
COASTAL CONDITIONS, THOUGH MARINE LAYER LIFTING MAY PUSH CEILINGS
CLOSER TO IFR. SATELLITE IS ALREADY SHOWING LOWER CLOUDS STARTING TO
FORM ALONG THE COAST. THE UPPER LEVEL LOW WILL AID IN DEEPENING THE
MARINE LAYER THROUGH THIS MORNING. THIS MEANS THAT MARINE INFLUENCE
WILL PUSH FURTHER INLAND. IN PARTICULAR, MARINE STRATUS COULD SURGE
UP THE RUSSIAN RIVER VALLEY THIS MORNING WHICH COULD RESULT IN IFR
CONDITIONS FOR KUKI.
MARINE
STRONG NORTH WINDS IN THE OUTER WATERS HAVE GRADUALLY
WEAKENED AND CONTINUE TO PUSH FURTHER OFFSHORE INTO VERY EARLY
THURSDAY MORNING WITH SHORT PERIOD SEAS SLOWLY FALLING MOSTLY BELOW
6 FEET BY FRIDAY. WINDS WILL BE MOSTLY CALM FRIDAY WITH MODERATE
NORTH WINDS REBUILDING AND PUSHING CLOSE TO SHORE SATURDAY AND
SUNDAY.
/JHW
FIRE WEATHER
A NOW RECEDING HEATWAVE HAS LEFT FUELS MUCH DRIER
THAN THEY WERE JUST ONE WEEK AGO WITH ERC BROADLY NEAR THE 90TH
PERCENTILE ACROSS THE INTERIOR. ERC IS FORECAST TO REMAIN HIGH
DESPITE INCREASING RH OVER THE COMING DAYS. OVERALL WEATHER
CONDITIONS WILL GREATLY MODERATE THROUGH FRIDAY WITH HIGHS MOSTLY IN
THE 80S, INCREASING MARINE INFLUENCE, AND RH CLOSER TO 30 PERCENT.
WINDS WILL REMAIN GENTLE AND TERRAIN DRIVEN.
THAT SAID, THE APPROACHING TROUGH SET TO BRING COOLER AND MORE MOIST
CONDITIONS TO NORTHWEST CALIFORNIA WILL ALSO PULL SOME TROPICAL
MOISTURE COMBINED WITH INCREASING INSTABILITY. IN COMBINATION, THESE
TWO FACTORS COULD CREATE SOME VERY ISOLATED, MOSTLY DRY,
THUNDERSTORMS THURSDAY AFTERNOON IN FAR NE TRINITY COUNTY (10%
CHANCE). SMALL WAVES ROTATING AROUND THE TROUGH MAY TRIGGER
CONVECTION OVERNIGHT. SOME HIGH RESOLUTION MODELS HINT AT WEAK STORM
ACTIVITY IN THE EARLY MORNING HOURS (ALSO 10% CHANCE FRIDAY. MUCH
MORE ROBUST ACTIVITY IS LIKELY (25% CHANCE) ACROSS NORTHERN HUMBOLDT
AND TRINITY COUNTIES BY FRIDAY EVENING WITH LOWER CHANCES AS FAR
SOUTH AS THE YOLLA BOLLYS. STORM MOTION APPEARS SLOW AND ISOLATED
OVERALL, BUT IGNITIONS ARE STILL VERY LIKELY GIVEN THE CURRENT ERC
VALUES. ANY STORMS COULD ALSO PRODUCE SOME RAIN AND GUSTY ERRATIC
OUTFLOW WINDS. /JHW
EKA WATCHES/WARNINGS/ADVISORIES
CA...
FIRE WEATHER WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY
EVENING FOR CAZ403-406-409-410.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 3 AM PDT THURSDAY FOR PZZ450-470-
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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