639  
FXUS66 KEKA 310751 CCA  
AFDEKA  
 
AREA FORECAST DISCUSSION...CORRECTED  
NATIONAL WEATHER SERVICE EUREKA CA  
1251 AM PDT SUN AUG 31 2025  
   
SYNOPSIS
 
NEAR SEASONAL AVERAGE TEMPERATURES WILL CONTINUE  
THROUGH THE WEEKEND. A WARMING TREND WILL INCREASE THE HEATRISK  
AND FIRE WEATHER THREAT AS LOW RH AND HOT TEMPERATURES BUILD  
ACROSS THE INTERIOR ON MONDAY AND THEN PEAK ON TUESDAY. THE COAST  
IS EXPECTED TO SEE NIGHT AND MORNING CLOUDS WITH SOME AFTERNOON  
CLEARING MOST DAYS. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS ON  
TUESDAY IN THE INTERIOR.  
 

 
   
DISCUSSION
 
THE UPPER LEVEL LOW CONTINUES TO REMAIN NEARLY  
STATIONARY OFF THE PACIFIC NORTHWEST COAST. THIS CONTINUES TO  
BRING MOSTLY SUNNY SKIES AND MODERATE SEASONAL TEMPERATURES. THE  
COOLER AIR ALOFT CONTINUES TO KEEP THE MARINE INVERSION WEAK  
ALLOWING STRATUS CLEARING IN THE AFTERNOON. THIS PATTERN IS  
EXPECTED TO CONTINUE TODAY WITH HIGHS IN THE UPPER 80S TO MID 90S  
ACROSS THE INTERIOR. MONDAY HIGH PRESSURE STARTS TO BUILD IN FROM  
THE SOUTH AND PUSH THE UPPER LEVEL LOW NORTH. THIS WILL WARM  
INLAND TEMPERATURES BY AROUND 5 DEGREES. THIS WILL ALSO STRENGTHEN  
THE MARINE INVERSION AND COASTAL CLOUDS MAY BE A BIT MORE  
PREVALENT.  
 
SOUTHWESTERLY WINDS ALOFT WILL CONTINUE TO PUSH THE SMOKE FROM THE  
ACTIVE WILDFIRES IN SISKIYOU AND TRINITY COUNTIES TOWARD NORTHEAST  
OUT OF THE AREA THROUGH MONDAY. THE EXCEPTION WILL BE AREAS NORTH  
OF THE PEAK FIRE BETWEEN TRINITY LAKE AND GRANITE PEAK. THERE  
WILL LIKELY BE LOCAL TERRAIN EFFECTS THAT WILL CONTINUE TO BRING  
SMOKE TO THE VALLEYS IN ALL DIRECTIONS NEAR THE FIRES. THIS WILL  
BE ESPECIALLY TRUE IF THE FIRE IS BURNING BELOW THE INVERSION AND  
THE SMOKE IS TRAPPED. FOR DETAILS VISIT WEATHER.GOV/EKA AND CHECK  
OUT THE AREA SMOKE FORECAST ON THE BOTTOM OF THE MAIN PAGE.  
 
TUESDAY THE FORECAST GETS A LITTLE MORE TRICKY. A SHORTWAVE  
MOVING UP THE WEST SIDE OF THE RIDGE AND THIS MAY BRING SOME  
MOISTURE AND INSTABILITY. THERE IS THE POTENTIAL FOR THUNDERSTORMS  
ACROSS THE INTERIOR DUE TO THIS. THERE IS LIFT FROM THE SHORTWAVE  
AND STEEP LAPSE RATES FROM THE COOLER AIR ALOFT. THE REMAINING  
QUESTION IS IF THERE WILL BE ENOUGH MOISTURE. PWATS ON THE MODELS  
ARE ONLY PROGGED TO BE AROUND 0.60 TO 0.70 INCHES. IF ANY STORMS  
DO FORM, THEY WILL LIKELY BE FAIRLY DRY. THE NAM SHOWS STORM BASES  
AROUND 10,000 FEET. FOR NOW WILL KEEP THE SLIGHT CHANCE FOR  
THUNDERSTORMS ACROSS TRINITY COUNTY.  
 
TUESDAY WILL LIKELY BE THE ABOUT THE HOTTEST DAY OF THE WEEK WITH  
HIGHS SEVERAL DEGREES WARMER THAN MONDAY. THIS IS EXPECTED TO  
BRING A MODERATE HEAT RISK TO THE AREA AND A HEAT ADVISORY MAY BE  
NEEDED IN PORTIONS OF THE INTERIOR. HOWEVER THE MODELS ARE SHOWING  
TEMPERATURES TRENDING SLIGHTLY COOLER.  
 
WEDNESDAY THE SHORTWAVE IS EXPECTED TO BE NORTH OF THE AREA. EVEN  
THE SLOWER SOLUTION OF THE ECMWF HAS PUSHED THE INSTABILITY NORTH  
OF THE AREA BY THE AFTERNOON ENDING THE THREAT FOR THUNDERSTORMS.  
TEMPERATURES ARE EXPECTED TO BE SIMILAR TO TUESDAY. THURSDAY AND  
FRIDAY A GRADUAL COOLING TREND IS EXPECTED, ALTHOUGH TEMPERATURES  
ARE EXPECTED TO REMAIN HOT. MKK  
 

 
   
AVIATION
 
AS TWIN LOW PRESSURE SYSTEMS SPIN NEAR AND FAR OFF  
OF THE COASTLINE, THE NEAREST CYCLONIC MOTION IS EJECTING MOISTURE  
BANDS TOWARDS THE PACNW WITH MOST OF IT MISSING OUR CWA. CIRRUS  
CLOUDS DENOTE COLDER TEMPS ALOFT BUT MERIDIONAL FLOW FROM THE NORTH  
IS THE PREVAILING CARDINAL DIRECTION AS OF 02Z SATURDAY EVENING.  
MODELS INDICATE THAT LIGHT SOUTHERLY FLOW WILL FILL IN AT KCEC EARLY  
SUNDAY MORNING, CALM TO LIGHT WINDS MIGHT USHER IN LOW OVERCASTS  
CLOUD DECKS BY MIDNIGHT, BRINGING IFR/LIFR CONDITIONS FOR A FEW  
HOURS. IMPROVED FLIGHT CONDITIONS BY LATE SUNDAY MORNING AT KCEC  
WITH SIMILAR CONDITIONS AT KACV WITH AN EASTERLY BEARING THAT WILL  
BRING VFR SOONER THAN JACK MCNAMARA FIELD. KUKI IS EXPECTED TO HAVE  
LIGHT NORTHERLY WINDS AND PREVAILING VFR CONDITIONS. NORTHERLY WINDS  
COULD GUST UP BY THE LATE AFTERNOON AT KUKI 13-16KTS. /EYS  
 

 
   
MARINE
 
NORTHERLY WINDS CONTINUE TO INCREASE IN THE LEE OF CAPE  
MENDOCINO, WITH GUSTS OF 25-30 KTS FORECAST SUNDAY AFTERNOON INTO  
THE EVENING. MODELS ARE BEGINNING TO RESOLVE A FETCH OF NORTHERLY  
WINDS IN THE NORTHERN OUTER WATERS, LIKELY TO BUILD AND FILL IN  
MONDAY. SMALL CRAFT ADVISORIES MAY NEED TO BE HOISTED TO COVER THE  
CONDITIONS. STAY TUNED IN.  
 
SEAS REMAIN MILD, WITH COMBINED SEAS OF 3FT AS OF SATURDAY NIGHT. A  
SMALL LONG-PERIOD SOUTHERLY SWELL CONTINUES AND WILL PERSIST TROUGH  
THE WEEKEND. HIGHER SEAS BUILDING FROM 4 TO 6 FT BY SUNDAY EVENING,  
SOUTH OF CAPE MENDOCINO. STRONGER WINDS MAY REACH NEARSHORE  
MENDOCINO SUNDAY AFTERNOON, WITH GUSTS PEAKING AROUND 25-30 KTS. BY  
SUNDAY NIGHT INTO MONDAY, WINDS INCREASE IN THE NORTHERN OUTER  
WATERS. THIS GENERAL PATTERN CONTINUES INTO MID NEXT WEEK. /JB  
/EYS  
 

 
   
EKA WATCHES/WARNINGS/ADVISORIES
 
 
CA...  
NONE.  
NORTHWEST CALIFORNIA COASTAL WATERS...  
SMALL CRAFT ADVISORY FROM 11 AM SUNDAY TO 11 PM PDT MONDAY  
FOR PZZ455.  
 
SMALL CRAFT ADVISORY FROM 5 AM SUNDAY TO 11 PM PDT MONDAY  
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.  
 
VISIT US AT HTTPS://WWW.WEATHER.GOV/EUREKA  
 
FOLLOW US ON FACEBOOK AND TWITTER AT:  
HTTPS://WWW.FACEBOOK.COM/NWSEUREKA  
HTTPS://WWW.TWITTER.COM/NWSEUREKA  
 
FOR FORECAST ZONE INFORMATION  
SEE THE FORECAST ZONE MAP ONLINE:  
HTTPS://WWW.WEATHER.GOV/IMAGES/EKA/ZONEMAP.PNG  
 
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