598  
FXUS66 KEKA 200555  
AFDEKA  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE EUREKA CA  
1055 PM PDT MON MAY 19 2025  
   
SYNOPSIS  
WARM AND DRY CONDITIONS EXPECTED THROUGH WEDNESDAY AS HIGH  
PRESSURE BUILDS INTO THE EASTERN PACIFIC. UPPER LEVEL DISTURBANCES  
POSSIBLE LATE THIS WEEK AND WEEKEND WITH COOLING AND POTENTIAL FOR  
LIGHT RAIN.  
 
 
   
DISCUSSION  
A WEAK FRONTAL BOUNDARY MOVED ACROSS THE REGION THIS  
AFTERNOON/EVENING, PROVIDING A LIFTING MECHANISM FOR DRIZZLE TO  
DEVELOP ALONG THE COAST WITHIN AN ALREADY WIDESPREAD MARINE CLOUD  
LAYER. VERY LITTLE ACCUMULATIONS WERE RECORDED - CHANCES WILL  
CONTINUE TO DETERIORATE OVERNIGHT. AS MENTIONED IN THE PREVIOUS  
DICUSSION, COOLER TEMPERATURES COULD PRODUCE SOME PATCHY FROST IN  
INTERIOR VALLEYS OF TRINITY COUNTY, BUT CLOUD COVER COULD BE A  
HINDRANCE.  
 
STRATUS WILL BECOME DISORGANIZED AND SCATTER OVERNIGHT INTO TUESDAY  
AS A RIDGE BUILDS INTO THE PNW. BREEZY NNW WINDS EXPECTED,  
ESPECIALLY ALONG THE COAST. HI-RES MODELS INDICATE HIGH TEMPERATURES  
IN THE 70'S AND LOW 80'S BENEATH MOSTLY CLEAR SKIES. MINOR HEAT RISK  
WILL BEGIN TO CREEP INTO THE EASTERN PORTIONS OF LAKE AND MENDOCINO  
COUNTY THROUGH WEDNESDAY, BUT NO MAJORLY CONCERNING.  
 
WEDNESDAY STILL APPEARS TO BE WARMEST DAY OF THE WEAK AS HIGH  
PRESSURE CONTINUES TO BUILD. WARM AND DRY CONDITIONS WITH HIGHS IN  
THE MID TO UPPER 80'S ARE EXPECTED ACROSS THE INTERIOR; COAST WILL  
BE DAMPENED BY RETURNING MARINE STRATUS. NBM PROBABILITIES DROP OFF  
SIGNIFICANTLY BETWEEN 85 AND 90 DEGREES - THIS MAY BE THE CAP FOR  
LAKE AND MENDOCINO COUNTIES, WITH POTENTIAL FOR THE HOTTEST TEMPS  
IN UKI AND COVELO. RH VALUES WILL DIP INTO THE 20-30% RANGE EAST  
OF THE COAST RANGES. BREEZY CONDITIONS WITH 10 TO 20 MPH GUSTS  
POSSIBLE IN LAKE COUNTY WEDNESDAY AFTERNOON WILL ENHANCE FIRE  
WEATHER CONDITIONS, BUT DOES NOT QUITE MEET RED FLAG CRITERIA,  
ESPECIALLY WITH CURRENT STATUS OF FUELS.  
 
THURSDAY AND FRIDAY BROAD/WEAK TROUGHING WILL DRIFT BY TO OUR  
NORTH, BUT WILL NOT HAVE MUCH MORE EFFECT THAN MID LEVEL CLOUD  
COVER. A SHORTWAVE DIPPING INTO NORCAL FRIDAY INTO SATURDAY COULD  
BRING SOME LIGHT SHOWERS TO NORTHERN COUNTIES. A MORE SIGNIFICANT  
PATTERN CHANGE IS POSSIBLE SUNDAY THROUGH EARLY NEXT WEEK. MODEL  
CLUSTERS ARE NOT YET ALIGNED BUT VERY LOW POTENTIAL FOR RAINFALL IS  
STILL POSSIBLE.  
 
 
   
AVIATION  
NORTHERLIES INCREASE LATER TONIGHT INTO TUESDAY MORNING  
AND SHOULD SCOUR OUT THE LOW LEVEL MOISTURE OVER COASTAL AERODROMES.  
LINGERING MVFR CEILINGS ARE STILL LIKELY (60% CHANCE) TUE AM,  
HOWEVER. OTHERWISE, VFR CONDITIONS WITH GUSTY NORTH TO NORTHWESTERLY  
WINDS ARE FORECAST FOR KUKI. THERE IS A 50% CHANCE FOR LOW LEVEL  
TURBULENCE AND/OR LOW LEVEL SPEED SHEAR UKI AND VICINITY OVERNIGHT  
AS SURFACE GUSTINESS DECOUPLES. GUSTY NORTHERLY AND NORTHWESTERLY  
WINDS AND SHALLOW LOW LEVEL TURBULENCE AND/OR LOW LEVEL SPEED SHEAR  
INCREASES THROUGHOUT DURING THE DAY ON TUESDAY. DB/MH  
 
 
   
MARINE  
MARINE CONDITIONS ARE FORECAST TO DETERIORATE ON TUESDAY  
AS NORTHERLY WINDS AND STEEP WAVES INCREASE THROUGH THE DAY. HREF  
PROBABILISTIC GUIDANCE CONTINUES TO SUPPORT PEAK GUSTS TO 35-40KT IN  
THE LEE OF CAPE MENDOCINO AS AN EXPANSION FAN GROWS THROUGH THE DAY  
ON TUESDAY AND REACHES MAXIMUM COVERAGE BY LATE AFTERNOON INTO THE  
EVENING HOURS. A SMALLER AND SHORTER DURATION EXPANSION FAN REGION  
ALSO DEVELOPS IN THE LATE AFTERNOON ACROSS THE NORTHERN WATERS,  
AROUND AND JUST DOWNWIND OF PT ST GEORGE. COVERAGE APPEARS MINIMAL  
FOR A GALE WARNING FOR THE NORTHERN WATERS. FOR NOW WILL HOIST  
ADVISORIES FOR SMALL CRAFT GIVEN THE RAMP UP OF STEEP NORTHERLY  
WAVES OF 6-8 FT ON TOP OF AN INCOMING NW SWELL OF 8-10 FT. COMBINED  
SEAS (SIGNIFICANT WAVE HEIGHTS) ARE FORECAST TO REACH 10-13 FEET,  
HIGHEST SOUTH OF CAPE MENDO, BY TUE AFTERNOON AND EVENING. MARINE  
CONDITIONS ARE FORECAST TO EASE UP TOWARD THE END OF THE WEEK,  
EXCEPT SOUTH OF CAPE MENDOCINO WHERE WIND AND SEAS WILL LIKELY  
REMAIN HAZARDOUS FOR SMALL CRAFT AND INEXPERIENCED MARINERS. DB/MH  
 
 
   
EKA WATCHES/WARNINGS/ADVISORIES  
 
CA...  
NONE.  
NORTHWEST CALIFORNIA COASTAL WATERS...  
SMALL CRAFT ADVISORY FROM 3 PM TUESDAY TO 3 AM PDT  
WEDNESDAY FOR PZZ450.  
 
SMALL CRAFT ADVISORY UNTIL 9 PM PDT WEDNESDAY FOR PZZ455.  
 
SMALL CRAFT ADVISORY FROM NOON TUESDAY TO 9 PM PDT  
WEDNESDAY FOR PZZ470.  
 
SMALL CRAFT ADVISORY UNTIL NOON PDT TUESDAY FOR PZZ475.  
 
GALE WARNING FROM NOON TUESDAY TO 3 AM PDT WEDNESDAY FOR  
PZZ475.  
 
 
 
 
 
VISIT US AT HTTPS://WWW.WEATHER.GOV/EUREKA  
 
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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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