087  
FXUS66 KEKA 080717  
AFDEKA  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE EUREKA CA  
1217 AM PDT WED OCT 8 2025  
   
SYNOPSIS
 
AN APPROACHING TROUGH WILL COOL TEMPERATURES TODAY.  
RAIN CHANCES INCREASE EARLY FRIDAY WITH MUCH COOLER CONDITIONS  
LIKELY. COOLER AND PERHAPS WETTER WEATHER LIKELY TO CONTINUES INTO  
THE WEEKEND AND EARLY NEXT WEEK.  
 

 
   
DISCUSSION
 
CLEAR SKIES AND DRY CONDITIONS CONTINUES TO BRING  
CHILLY LOW TEMPERATURES THE INTERIOR AREAS. SLIGHTLY WARMER HIGH  
TEMPERATURES ON TUESDAY AND DIMINISHED OFFSHORE FLOW MAY KEEP  
INTERIOR VALLEY LOW TEMPERATURES A COUPLE DEGREES WARMER THIS  
MORNING WITH GENERALLY HIGH 30S OR 40S FORECAST. TEMPERATURES OF 36  
OR LESS ARE UNLIKELY AND FROST POTENTIAL IS LOW.  
 
LOW PRESSURE WILL GRADUALLY FILL IN AND DEEP TROUGH DIPPING ACROSS  
THE EASTERN PACIFIC WILL GRADUALLY COME TO DOMINATE THE WEATHER  
PATTERN THROUGH THE END OF THE WEEK. FLOW SWITCHING ONSHORE AND MORE  
MARINE AIR WILL GENERALLY ALLOW FOR A MARINE LAYER TO REFORM ALONG  
SHORE BY THIS EVENING. EVEN WITH SKIES STAYING MOSTLY CLEAR, ONSHORE  
FLOW WILL MOST LIKELY ALLOW FOR COASTAL HIGHS TO RETURN TO THE 60S.  
WEAKENING HIGH PRESSURE WILL ALSO ALLOW THE INTERIOR TO COOL BACK  
INTO THE 70S OR 80S TODAY. BUILDING MIDLEVEL CLOUDS WILL AID IN  
FURTHER COOLING THURSDAY.  
 
THE TROUGH CONTINUES TO APPROACH THE AREA THURSDAY. SOUTH FLOW AHEAD  
OF THE TROUGH ALONG WITH OROGRAPHIC LIFT SUPPORT A FEW LIGHT RAIN  
SHOWERS OVER TRINITY COUNTY. CAMS ARE STARTING TO SHOW SOME SUPPORT  
THIS, BUT ANY RAIN AMOUNTS ARE EXPECTED TO BE MINOR. AS THE TROUGH  
MOVES INLAND THURSDAY INTO FRIDAY, TROPICAL MOISTURE PULLED IN FRONT  
OF THE TROUGH WILL ENABLE AT LEAST LIGHT RAIN ACROSS THE AREA. RAIN  
AMOUNTS REMAIN UNCERTAIN. DETERMINISTIC MODELS SHOW ONLY MARGINAL  
(0.6 TO 0.8 IN) PRECIPITABLE WATER AMOUNTS. STILL, CONSISTENT STRONG  
SOUTHWEST FLOW ALOFT MAY HELP MAKE UP FOR MARGINAL AMOUNTS THANKS TO  
CONSISTENT MOISTURE TRANSPORT AND OROGRAPHIC FORCING. NBM GENERALLY  
SEEMS TO BE ERRING ON THE HIGH END OF GLOBAL ENSEMBLES WITH A WIDE  
SPREAD OF 0.5 AND 2.0 INCHES OF RAIN ALONG THE NORTH COAST, MOST  
LIKELY BEGINNING EARLY FRIDAY MORNING. A FEW THUNDERSTORMS ARE  
POSSIBLE WHICH COULD BRING LOCALIZED HIGHER AMOUNTS OF RAIN TO THE  
COASTAL AREAS. GENERALLY LESS THAN 0.5 INCHES OF RAIN IS MOST LIKELY  
FOR THE SOUTHERN HALF OF THE AREA WITH A 25% CHANCE OF NO  
PRECIPITATION AT ALL.  
 
LIGHTER RAIN SHOWERS WILL CONTINUE INTO THE WEEKEND WITH ONLY A 30-  
50% CHANCE OF ADDITIONAL WETTING RAIN EACH SATURDAY AND SUNDAY,  
MAINLY IN THE NORTHERN HALF OF THE AREA. EVEN WITHOUT RAIN, COOLER  
AND MORE MOIST CONDITIONS ARE LIKELY TO PERSIST INTO EARLY NEXT WEEK  
WITH A GOOD CHANCE OF WIDESPREAD INTERIOR FROST SHOULD CONDITIONS  
DRY OUT FAST ENOUGH BY SUNDAY AND MONDAY.  
 
THERE IS INCREASING CONFIDENCE AMONG ENSEMBLE MEMBERS FOR ANOTHER  
SYSTEM APPROACHING THE AREA EARLY NEXT WEEK. CONFIDENCE IS CURRENTLY  
LOW ON ANY IMPACTS, BUT SOME MODELS ARE SHOWING A SIMILARLY COLD, IF  
NOT COLDER, AIRMASS MOVING OVERHEAD. THIS COULD BRING MORE FROSTY OR  
FREEZING CONDITIONS IN THE INTERIOR INTO EARLY NEXT WEEK. JHW/JB  
 

 
   
AVIATION...(06Z TAFS)
 
MOSTLY VFR CONDITIONS FOR THE REMAINDER OF  
TUESDAY EVENING AT THE COASTAL TERMINALS. STATISTICAL GUIDANCE IS  
SUGGESTING A REDUCTION IN FLIGHT CATEGORIES (IFR) BY 8-9Z INTO EARLY  
WEDNESDAY MORNING. WITH MINIMAL CLOUD COVER, RADIATION FOG COULD  
PLAY A ROLE FOR A REDUCTION IN VISIBILITY BUT AS AN UPPER LEVEL LOW  
APPROACHES, STRATUS IS SPREADING FROM THE SOUTH AND OFFSHORE FROM  
THE NORTH. A CONSIDERABLE BLANKET IS FORMING OFF OF THE SONOMA AND  
MARIN COUNTY COASTS, AT THIS POINT IT LOOKS AS IF ADVECTION INLAND  
WILL BE HELD TO THE SHORELINE. THREATS TO KUKI ARE MINIMAL.  
 
TAFS AT KACV AND KCEC DO HAVE LOWER VISIBILITY FOR THE EARLY MORNING  
TEMPO'D JUST IN CASE. EASTERLY WINDS AT KACV AND KCEC COULD KEEP  
COASTAL STRATUS AT A MINIMUM OVERNIGHT INTO WEDNESDAY EARLY MORNING.  
WINDS VEER FROM THE NW BY NOON WEDNESDAY FOR THE COASTAL TERMINALS.  
LIGHT TO CALM WINDS AT KUKI THROUGH THE TAF PERIOD WITH SOUTHERLIES  
PICKING UP BY THE AFTERNOON WEDNESDAY. /EYS  
 

 
   
MARINE
 
NORTHERLY WINDS WILL INCREASE LATE TONIGHT INTO WED  
BEHIND A WEAK FRONT FORECAST TO PASS IN PAC NW ON WED. GREATEST  
COVERAGE FOR GUSTS TO 25-30KT IS OVER THE OUTER WATERS. GUSTS TO  
30KT WILL BE POSSIBLE (40-60% CHANCE) INSIDE 10NM AND DOWNWIND OF  
CAPE MENDOCINO. CHANCES ARE ARE LOWER (10-20%) AROUND PT ST GEORGE.  
STEEP NORTHERLY WIND WAVES WILL ALSO REBUILD TO 6 TO 8 FT BY WED AND  
SEAS WILL ONCE AGAIN BECOME HAZARDOUS TO SMALL CRAFT. NORTHERLIES  
WILL DIMINISH AND EVENTUALLY TURN SOUTHERLY FOR THE NORTHERN WATERS  
ON THU. SOUTHERLIES WILL LIKELY STRENGTHEN IN ADVANCE OF A FRONT ON  
FRIDAY. NBM PROBABILITIES ARE NOT VERY HIGH AROUND 15 TO 25% FOR  
GUSTS OVER 25 MPH. LOOKING AT THE DETERMINISTIC GUIDANCE, SUSPECT  
THERE WILL BE HIGHER GUSTS. LACK OF A LONG SOUTHERLY FETCH MAY LIMIT  
THE SHORT PERIOD WAVE GENERATION TO ONLY 4 TO 5 FT FROM THE SW.  
THERE ARE INDICATIONS FROM THE GEFS AND ECMWF ENS FOR STRONGER  
NORTHERLIES TO RAMP UP TOWARD THE LATTER PORTION OF THE WEEKEND.  
 

 
   
COASTAL FLOODING
 
THE FULL MOON HAS BROUGHT HIGHER THAN NORMAL  
TIDES TO THE COASTLINES. THE NORTH SPIT TIDE GAUGE IS FORECAST TO  
REACH 7.91 FT MLLW AROUND 1 PM THIS AFTERNOON. WITH THE ANOMALY  
ADDED THIS WOULD BE AROUND 8.80 FT MLLW, WHICH COULD CAUSE COASTAL  
FLOODING TO KING SALMON AND IN THE ARCATA BOTTOMS BY JACKSON RANCH  
RD. BUILDING NORTHERLY WINDS TODAY MAY LOWER THE ANOMALY  
SLIGHTLY, KEEPING BELOW 8.8 FT AT LEAST FOR TODAY. THE TIDES ARE  
FORECAST TO BE HIGHER THURSDAY AND FRIDAY, REACHING 8.03 FT MLLW  
AROUND 1:30 PM THURSDAY AND 7.94 FT MLLW AROUND 2:00 PM FRIDAY.  
SOUTHERLY WINDS AHEAD OF THE SYSTEM MAY INCREASE THE ANOMALY  
WHICH COULD LEAD TO MINOR COASTAL FLOODING. JB  
 

 
   
EKA WATCHES/WARNINGS/ADVISORIES
 
 
CA...  
NONE.  
NORTHWEST CALIFORNIA COASTAL WATERS...  
SMALL CRAFT ADVISORY FROM 6 AM WEDNESDAY TO MIDNIGHT PDT  
WEDNESDAY NIGHT FOR PZZ470.  
 
SMALL CRAFT ADVISORY FROM 6 AM WEDNESDAY TO 6 AM PDT  
THURSDAY 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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