895
FXUS66 KEKA 182039
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
139 PM PDT THU JUN 18 2026
SYNOPSIS
TEMPERATURES WILL CONTINUE TO COOL THROUGH FRIDAY WITH
MARINE INFLUENCE LIFTING ALONG SHORE AND PUSHING MORE INLAND.
SCATTERED DRY THUNDERSTORMS WILL IMPACT HIGH TERRAIN LOCATIONS OVER
THE INTERIOR FRIDAY.
KEY MESSAGES
- TEMPERATURES EASE THROUGH SATURDAY WITH ONLY MINOR HEATRISK
- SLIGHT CHANCE OF DRY THUNDERSTORMS OVER HIGH TERRAIN OF NORTHERN
HUMBOLDT AND TRINITY COUNTIES FRIDAY MORNING.
- WARMING TREND RETURNS NEXT WEEK.
DISCUSSION
AN UPPER LEVEL TROUGH APPROACHING THE AREA HAS HELPED
TO MORE RAPIDLY DECREASE TEMPERATURES TODAY. MOST INTERIOR VALLEYS
HAVE STRUGGLED TO EVEN REACH 80 WITH INCREASING MARINE INFLUENCE
PUSHING RH OVER 30 PERCENT. THE TROUGH WILL CROSS INLAND TOMORROW
AND BRING MORE CLOUD COVER AND FURTHER WARMING.
THE TROUGH WILL ALSO HELP INCREASE UPPER LEVEL INSTABILITY. COMBINED
WITH A MOISTURE SURGE UP THE SACRAMENTO VALLEY, THERE IS POTENTIAL
FRO THUNDERSTORMS AS EARLY AS SUNRISE ON FRIDAY MORNING. HIGH
RESOLUTION MODELS SHOW A WEAK CONVECTIVE SIGNATURE, BUT CHANCES OF
ACTUAL LIGHTNING REMAIN LOW TO MODERATE AT BEST (15%). MODELS
GENERALLY FOCUS CONVECTION OVER NORTHERN HUMBOLDT AND TRINITY
COUNTIES THOUGH JUST A FEW WANT TO PUT STORMS AS FAR SOUTH AND WEST
AS THE KING RANGE. UNCERTAINTY REMAINS VERY HIGH, AS MANY MODEL
SOUNDING SHOW MOISTURE TOO HIGH IN THE UNSTABLE LAYER WITH WEAK
FORCING, MAKING LIGHTNING POTENTIAL QUESTIONABLE. THAT SAID, THESE
SETUPS OR NORMALLY POORLY RESOLVED BY MODELS IN BOTH OVER AND UNDER
FORECAST DIRECTIONS. ISOLATED, SURFACE BASED STORMS ARE POSSIBLE IN
THE AFTERNOON THOUGH CHANCES HAVE GENERALLY DROPPED FOR THOSE (10%).
OTHERWISE COOL CONDITIONS WILL BOTTOM OUT ON SATURDAY WITH GRADUALLY
WARMING AND NON-IMPACTFUL WEATHER NEXT WEEK. THOUGH TEMPERATURES
WILL RETURN TO THE 90S ONLY MODERATE HEATRISK IS EXPECTED. /JHW
AVIATION
A PERSISTENT MARINE LAYER HAS AGAIN BLANKETED THE COAST
TODAY GENERATING LIFR CONDITIONS INT HE MORNING. APPROACHING
INSTABILITY FROM AN UPPER LEVEL TROUGH HAS HELPED LIFT CEILINGS TO
IFR WITH SOME SPORADIC SCATTERING TO VFR. IFR CONDITIONS WITH
ISOLATED AREAS OF LIFR CEILINGS ARE MOST LIKELY TO PERSIST OVERNIGHT
WITH ANOTHER INTRUSION OF LOW CEILINGS INTO THE RUSSIAN RIVER
VALLEY. INCREASING INSTABILITY WILL MOST LIKELY HELP FURTHER LIFT
CEILINGS ON FRIDAY. /JHW
&
MARINE
WINDS HAVE GENERALLY DROPPED TO GENTLE OR EVEN CALM ACROSS
ALL WATERS. MODERATELY STEEP SHORT PERIOD SEAS ARE GRADUALLY FALLING
AND WILL GENERALLY FALL BELOW 6 FEET FRIDAY MORNING. BEYOND THE WIND
WAVES, THERE IS A MINOR BUT PERSISTENT MID PERIOD NORTHWEST SWELL
AROUND 4 FEET THAT MAY BE MORE OBVIOUS WITH THE CALMER SEAS. NORTH
WINDS WILL GRADUALLY INCREASE AGAIN THIS WEEKEND WITH NEAR GALE FORCE
GUSTS IN THE OUTER WATERS BY SUNDAY AFTERNOON. THESE WINDS WILL PULL
CLOSER TO SHORE BRINING STEEP SHORT PERIOD SEAS TO ALL WATERS
THROUGH EARLY NEXT WEEK. /JHW
FIRE WEATHER
FIRE WEATHER CONDITIONS HAVE EASED SUBSTANTIALLY ALL
ACROSS THE AREA. TEMPERATURES HAVE STRUGGLED TO GET ABOVE 80 AND RH
HAS RISEN OVER 30 PERCENT EVEN FOR DRIER VALLEYS. WINDS REMAIN
GENERALLY LIGHT.
INCREASING CLOUD COVER WILL HELP FURTHER EASE TEMPERATURE AND RH ON
FRIDAY. THAT SAID, ERC VALUES REMAIN AROUND THE 85TH PERCENTILE DUE
TO THE PAST HEAT WAVE AND THERE IS A RISK OF DRY THUNDERSTORMS
FRIDAY MORNING. THE CHANCE OF STORMS IS GREATEST BETWEEN ABOUT 5 AM
FRIDAY AND NOON. STORMS IN THIS PERIOD ARE MOST LIKELY TO FORM OVER
NORTHERN TRINITY AND HUMBOLDT COUNTIES WITH JUST A FEW MODELS (LESS
THAN 10% CHANCE) PLACING THUNDERER FURTHER SOUTH AND CLOSER TO THE
COAST. THESE MORNING STORMS WOULD BE MOSTLY DRY AND FAST MOVING.
THAT SAID, UNCERTAINTY REMAINS HIGH WITH A 50% CHANCE OF NO
CONVECTION AT ALL. STORMS CHANCES ARE MORE LIMITED IN THE AFTERNOON
WITH LESS CHANCE FOR IGNITIONS. /JHW
EKA WATCHES/WARNINGS/ADVISORIES
CA...
RED FLAG WARNING FROM 8 AM TO 7 PM PDT FRIDAY FOR CAZ403-
406-409-410.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 5 PM PDT THIS AFTERNOON FOR
PZZ450-475.
SMALL CRAFT ADVISORY UNTIL 5 AM PDT FRIDAY FOR PZZ470.
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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