609  
FXUS66 KEKA 182013  
AFDEKA  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE EUREKA CA  
113 PM PDT SAT OCT 18 2025  
   
SYNOPSIS  
MILD WARMING AND DRYING WILL CONTINUE TODAY WITH  
COASTAL AREAS SLOWER TO CLEAR OUT. COOLER WEATHER AND VERY LIGHT  
COASTAL RAIN IS EXPECTED SUNDAY MORNING WITH WARMER WEATHER AGAIN  
EARLY NEXT WEEK WITH WETTER WEATHER BY NEXT WEEKEND.  
 
 
   
DISCUSSION  
TRANSIENT HIGH PRESSURE PEAKS ACROSS THE AREA  
TODAY, ALLOWING FOR THE HOTTEST INTERIOR VALLEYS TO REACH NEAR  
80. A WEAK, SHALLOW MARINE LAYER WILL PERSIST ALONG THE COAST WITH  
STRATUS ERODING AT A SLOW RATE. HREF AND OBSERVATIONS SHOW  
LINGERING LOW CLOUDS AT THE COAST AT LEAST UNTIL THE LATE  
AFTERNOON. AN INCOMING FRONT WILL PUSH LOW LEVEL CLOUDS AND  
MOISTURE ONTO THE COAST AROUND 10-12Z, EARLY SUNDAY MORNING.  
INITIAL MODEL RUNS HAD GREATER PRECIP ACCUMULATION WHICH HAS  
TRENDED DOWN CONSIDERABLY. MOST OF THE LIGHT RAIN IS EXPECTED TO  
FALL IN DEL NORTE 0.05-0.08 INCHES AND EVEN LESS ON THE COAST,  
CONFINED TO AREAS NORTH OF CAPE MENDOCINO.  
 
WEAK HIGH PRESSURE AND SLIGHT WARMING WILL LIKELY REASSERT  
ITSELF EARLY NEXT WEEK, THOUGH LOW PRESSURE PASSING TO THE  
SOUTHEAST WILL LIMIT THE AMOUNT OF WARMING WITH ONLY A MODERATE  
CHANCE (50%) OF SOME HIGHS EVEN OVER 80. STRONG OFFSHORE FLOW  
AROUND THE LOW WILL LIKELY HELP BETTER DRY CONDITIONS COMPARED TO  
THE CURRENTLY HIGH STUBBORN DEWPOINTS. WIDESPREAD PATCHY FROST  
WILL BE LIKELY (60% CHANCE) MONDAY MORNING, ESPECIALLY IN TRINITY  
COUNTY.  
 
THERE IS INCREASING CONFIDENCE IN LONG RANGE FORECASTS THAT A  
SIGNIFICANT RAIN EVENT WILL IMPACT THE AREA LATE NEXT WEEK. THOUGH  
HIGH UNCERTAINTY REMAINS, NBM ALREADY PLACES A 95% CHANCE OF WETTING  
RAIN ALL THE WAY ALONG THE NORTH COAST WITH AN 70% CHANCE OF 3 DAY  
RAINFALL OVER 3 INCHES AND A 25% CHANCE OF 3 DAY RAINFALL OVER 5  
INCHES. DESPITE THESE HIGH TOTALS FORM THE NBM, ENSEMBLE SPREADS  
REMAINS VERY LARGE, INDICATING GREAT POTENTIAL FOR LOWER END  
SCENARIOS TO STILL BE REALIZED. ON THE STRONGER END, SUCH AN EVENT  
WOULD LIKELY BE ACCOMPANIED BY STRONG WIND WITH SUCH RAINFALL  
AMOUNTS CAPABLE OF MODERATE FLOOD IMPACTS. /JHW /EYS  
 
 
   
AVIATION...18Z TAFS  
COASTAL STRATUS HAS SOCKED IN ALONG THE  
REDWOOD COAST TODAY. HREF, NAMNEST, AND LAMP MODELS SHOWS MINIMAL  
CLEARING FOR THE REST OF THE DAY. KCEC SHOWS A HIGHER CHANCE OF  
CLEAR SKIES BEFORE A COASTAL EDDY FILLS THE SKIES AGAIN THIS EVENING  
WITH FOG POTENTIAL. A WEAK FRONT IS EXPECTED TO PASS THROUGH THE  
AREA BETWEEN 11Z-17Z TOMORROW MORNING. PERIODS OF RAIN ARE POSSIBLE  
FOR HUMBOLDT AND DEL NORTE COUNTIES WITH DEGRADED VISIBILITIES AND  
LOW CLOUDS. CONDITIONS SHOULD CLEAR AND CALM BY 18Z TOMORROW IF HIGH  
RESOLUTION MODELS ARE CORRECT. INLAND, VFR IS EXPECTED WITH LIGHT  
WINDS AND MINIMAL IMPACTS FROM THE FRONTAL PASSAGE OUTSIDE OF THE  
NORTH COAST. FRONTAL PASSAGE IMPACTS CAN INCLUDE MOUNTAIN WAVES AND  
OROGRAPHIC CLOUDS NEAR TERRAIN. /DS  
 
 
   
MARINE  
A LONG PERIOD NORTHWEST SWELL IS BUILDING ACROSS THE  
WATERS THROUGH THE DAY, AND PEAKING TO 9-11 FEET AT 16 SECONDS THIS  
AFTERNOON. TONIGHT INTO THE MORNING, SOUTHERLY WINDS WILL DEVELOPED  
BRIEFLY ACROSS THE OUTER WATERS AS A WEAK FRONTAL SYSTEM MOVES  
THROUGH. NORTHERLY WINDS INCREASE AGAIN TOMORROW AFTERNOON AND  
STRENGTHENING THROUGH EARLY NEXT WEEK. GALE STRENGTH GUSTS ARE  
FORECAST AROUND AND SOUTH OF CAPE MENDOCINO SUNDAY AFTERNOON THROUGH  
SUNDAY NIGHT. A GALE WARNING HAS BEEN ISSUED FOR THE SOUTHERN OUTER  
WATERS FROM 5PM SUNDAY - 11AM MONDAY.  
 
A SECOND LARGER SWELL MOVE IN LATE SUNDAY THROUGH MONDAY. BREAKERS  
MAY REACH 20 FEET THROUGH THAT PERIOD. ADDITIONAL LARGE SWELLS ARE  
THEN LIKELY THROUGH NEXT WEEK WITH AN ACTIVE PACIFIC STORM TRACK.  
 
NORTHERLY WINDS WILL REMAIN SOMEWHAT STRENGTHENED INTO MID NEXT  
WEEK. THE NORTHERLY WIND PATTERN BREAKS DOWN THEREAFTER AS A STRONG  
TROUGH TAKES AIM AT THE VICINITY OF N CA. STRONG SOUTHERLY WINDS ARE  
POSSIBLE THURSDAY OR FRIDAY IF THIS SYSTEM TAKE A MORE SOUTHERLY  
TRACK. CHANCES FOR AT LEAST SUSTAINED GALE STRENGTH SOUTHERLIES AND  
LARGE SURF CONTINUE TO INCREASE THROUGH THE COMING WEEKEND WITH  
MODELS SHOWING A SIGNAL FOR ADDITIONAL CYCLONES. /DS  
 
 
   
EKA WATCHES/WARNINGS/ADVISORIES  
 
CA...  
BEACH HAZARDS STATEMENT UNTIL MIDNIGHT PDT TONIGHT FOR  
CAZ101-103-104-109.  
 
NORTHWEST CALIFORNIA COASTAL WATERS...  
SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR  
PZZ470.  
 
SMALL CRAFT ADVISORY UNTIL 5 PM PDT SUNDAY FOR PZZ475.  
 
GALE WARNING FROM 5 PM SUNDAY TO 11 AM 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.  
 
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FOR FORECAST ZONE INFORMATION  
SEE THE FORECAST ZONE MAP ONLINE:  
HTTPS://WWW.WEATHER.GOV/IMAGES/EKA/ZONEMAP.PNG  
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