970  
FXUS66 KEKA 022308  
AFDEKA  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE EUREKA CA  
308 PM PST TUE DEC 2 2025  
   
SYNOPSIS  
HIGH PRESSURE BUILD OVER THE AREA IS BRINGING OFFSHORE  
FLOW AND GENERALLY CLEAR SKIES TO THE AREA THROUGH THURSDAY ALONG  
WITH NIGHT AND MORNING VALLEY FOG. LIGHT RAIN IS POSSIBLE MAINLY  
IN HUMBOLDT AND DEL NORTE COUNTIES OVER THE WEEKEND.  
 
 
 
KEY MESSAGES:  
 
* KING TIDES FROM DECEMBER 3RD-7TH MAY LEAD TO MINOR COASTAL  
FLOODING IN LOW-LYING AREAS MAINLY AROUND HUMBOLDT BAY.  
 
* FROST IS POSSIBLE WEDNESDAY AND THURSDAY MORNING IN THE COLDER  
VALLEYS AND ALONG THE COAST.  
 
* DRY AND SEASONABLY COOL WEATHER EXPECTED THROUGH FRIDAY, FOLLOWED  
BY A CHANCE OF RAIN OVER THE WEEKEND.  
 
 
   
DISCUSSION  
HIGH PRESSURE OVER THE AREA IS BRINGING FAIRLY  
ROBUST OFFSHORE FLOW TO THE AREA TONIGHT. EAST WINDS WILL BRING  
BREEZY ON THE RIDGES BOTH WEDNESDAY AND THURSDAY MORNINGS. THESE  
ARE EXPECTED TO BE THE STRONGEST WEDNESDAY MORNING. GUSTS TO 30 TO  
35 MPH ARE POSSIBLE ON SOME OF THE HIGHER PEAKS, ESPECIALLY IN  
EASTERN LAKE COUNTY. THESE MAY MIX DOWN TO SOME OF THE NORTHEAST  
TO SOUTHWEST ORIENTED VALLEYS. THIS IS EXPECTED TO LIMIT FOG  
DEVELOPMENT AND MAY ALLOW FROST TO FORM IN THE SOME OF THE  
VALLEYS THAT HAVEN'T FROZEN YET. SO HAVE ISSUED A FROST ADVISORY  
FOR A NUMBER OF THESE AREAS. IT IS STILL POSSIBLE LOW CLOUDS WILL  
BE MORE WIDESPREAD THAN EXPECTED, BUT FOR NOW IT LOOKS LIKE FROST  
IS LIKELY. WEDNESDAY ANOTHER DRY DAY IS EXPECTED. ANY VALLEYS  
THAT DO FOG UP WILL LIKELY BE SLOW TO CLEAR OUT AND WARM UP  
DURING THE DAY. WEDNESDAY NIGHT INTO THURSDAY MORNING IS EXPECTED  
TO SEE LIGHTER WINDS ALOFT, BUT THEY AIR IS EXPECTED TO BE DRIER.  
THIS WOULD MAKE IT LIKELY TO BE SLIGHTLY COLDER THURSDAY MORNING.  
 
THURSDAY NIGHT INTO FRIDAY MORNING A SHORTWAVE COMING OVER THE  
RIDGE IS EXPECTED TO START BRINGING MORE CLOUDINESS TO THE AREA.  
THIS WILL LIKELY KEEP TEMPERATURES WARMER. IT IS POSSIBLE THIS  
COULD BRING SOME DRIZZLE TO THE NORTHERN COASTAL AREAS, BUT  
CONFIDENCE IS LOW ON THIS. FRIDAY AFTERNOON LOOKS LIKE THE FIRST  
CHANCE FOR SOME LIGHT RAIN AND THIS MAY CONTINUE THROUGH THE  
WEEKEND. THE BIG QUESTION IS HOW FAR SOUTH THIS RAIN WILL COME.  
THE CURRENT FORECAST KEEPS MOST OF IT IN DEL NORTE COUNTY WITH  
LESS THAN A QUARTER OF AN INCH IN NORTHERN HUMBOLDT COUNTY. DEL  
NORTE COUNT MAY SEE OVER A HALF INCH. HOWEVER THIS IS A SMALL  
SYSTEM AND A SLIGHT SHIFT FARTHER NORTH OR SOUTH COULD REALLY  
CHANGE THE RAINFALL TOTALS. THIS IS HIGHLIGHT IN THE 75TH AND 25TH  
PERCENTILES FROM THE NBM. THE 25TH PERCENTILE FOR CRESCENT CITY  
SHOWS 0.2 INCHES WHILE THE 75TH PERCENTILE SHOWS 1.1 INCHES. IN  
EUREKA AND MUCH OF HUMBOLDT AND TRINITY COUNTIES THOSE AMOUNTS  
RANGE FROM 0.00 TO 0.5 INCHES. FARTHER SOUTH AND EAST IN SOUTHERN  
TRINITY, MENDOCINO AND LAKE COUNTIES EVEN THE HIGH ENDS AMOUNTS  
ARE LESS THAN A QUARTER INCH. EVEN IF THE HEAVIER AMOUNTS MAKE IT  
FARTHER SOUTH, THERE AREN'T EXPECTED TO BE MANY IMPACTS. MKK  
 
 
   
AVIATION  
HIGH PRESSURE AND OFFSHORE FLOW ARE BRINGING VFR  
CONDITIONS TO THE AREA THIS AFTERNOON. THESE ARE EXPECTED TO  
CONTINUE TONIGHT ALONG THE COAST AND SOME OF THE INLAND VALLEYS.  
THERE WILL BE SOME STRONGER NORTHEAST WINDS ALOFT AS WELL. THIS  
WILL HELP LIMIT SOME OF THE VALLEY FOG TONIGHT, ESPECIALLY IN THE  
NORTHEAST TO SOUTHWEST ORIENTED VALLEYS. THIS MAY ALSO BRING SOME  
LOW LEVEL WIND SHEAR OR TURBULENCE. 20 TO 30 KT OF NORTHEAST WIND  
ARE EXPECTED DOWN TO A FEW THOUSAND FEET ABOVE THE SURFACE. ANY  
FOG THAT DOES FORM TONIGHT SHOULD CLEAR OUT BY MID TO LATE MORNING  
WEDNESDAY. MKK  
 
 
   
MARINE  
NORTHERLY WINDS HAVE STRENGTHENED AND MOVED CLOSER TO  
THE COAST THIS AFTERNOON. GALE FORCE GUSTS UP TO 35 KTS ARE  
LIKELY OCCURRING IN THE OUTER WATERS, WITH GUSTS UP 20-25 KTS  
POSSIBLE NEARSHORE. STEEP SEAS HAVE STARTED TO INCREASE AND ARE  
COMBINING WITH THE NORTHERLY SWELL AROUND 10 FEET AT 15 SECONDS.  
COMBINED SEAS COULD REACH 10-14 FT BY EARLY WEDNESDAY MORNING.  
WINDS EASE SLIGHTLY BY WEDNESDAY BUT GUSTS UP TO 30 KTS ARE STILL  
POSSIBLE IN THE OUTER WATERS. WINDS AND SEAS EASE FURTHER THURSDAY  
AND FRIDAY, WITH THE MAIN EXCEPTION BEING THE EXPANSION FAN SOUTH  
OF CAPE MENDOCINO. CONDITIONS CONTINUE TO IMPROVE GOING INTO THE  
WEEKEND AS HIGH PRESSURE WEAKENS. MKK/JB  
   
COASTAL FLOODING  
HIGH ASTRONOMICAL TIDES ARE PREDICTED FROM  
THROUGH SUNDAY FOR NORTHWEST CALIFORNIA. WATER LEVELS REMAIN  
NEARLY A HAVE A FOOT ABOVE ASTRONOMICAL TIDES INSIDE HUMBOLDT BAY  
AND THIS MAY CAUSE MINOR FLOODING STARTING WEDNESDAY SO HAVE  
ISSUED A COASTAL FLOOD ADVISORY FOR HUMBOLDT BAY. THE TIDES  
CONTINUE TO GET HIGHER OVER THE NEXT SEVERAL DAYS AND ADDITIONAL  
FLOODING IS EXPECTED AROUND HUMBODLT BAY. OUTSIDE OF HUMBOLDT BAY  
THE TIDE GAUGES ARE SHOWING A SLIGHT NEGATIVE ANOMALY AND THE  
SWELL CONTINUES TO DIMINISH. AT THIS POINT WE AREN'T EXPECTING  
COASTAL FLOODING OUTSIDE OF HUMBOLDT BAY, BUT THIS WILL NEED TO BE  
WATCHED AS IT GETS CLOSER. MKK  
 
 
   
EKA WATCHES/WARNINGS/ADVISORIES  
 
CA...  
BEACH HAZARDS STATEMENT UNTIL 3 PM PST THIS AFTERNOON FOR  
CAZ101-103-104-109.  
 
FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM PST WEDNESDAY  
FOR CAZ103>106-109-112-113.  
 
NORTHWEST CALIFORNIA COASTAL WATERS...  
SMALL CRAFT ADVISORY UNTIL 10 AM PST WEDNESDAY FOR PZZ450.  
 
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM PST  
WEDNESDAY FOR PZZ455.  
 
SMALL CRAFT ADVISORY UNTIL 4 PM PST THIS AFTERNOON FOR  
PZZ470-475.  
 
GALE WARNING FROM 4 PM THIS AFTERNOON TO 8 AM PST WEDNESDAY  
FOR PZZ470-475.  
 
 
 
 
 
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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