382  
FXUS66 KEKA 020823  
AFDEKA  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE EUREKA CA  
1223 AM PST TUE DEC 2 2025  
   
SYNOPSIS  
HIGH RISK FOR SNEAKER WAVES THROUGH THIS AFTERNOON.  
KING TIDES RETURN TODAY AND THEN PEAK THURSDAY AND FRIDAY.  
CHANCES FOR FROST AND FREEZING TEMPERATURES INCREASE FOR AREAS  
CLOSER TO THE COAST AGAIN TONIGHT. DRY WEATHER EXPECTED TO  
PREVAIL FOR THIS WEEK, FOLLOWED BY A CHANCE FOR RAIN LATE FRIDAY  
AND OVER THE WEEKEND.  
 
 
 
KEY MESSAGES:  
 
* HIGH RISK OF SNEAKER WAVES IS EXPECTED ALONG THE NORTHWEST  
CALIFORNIA BEACHES THROUGH THE AFTERNOON.  
 
* KING TIDES FROM DECEMBER 2ND-7TH, AND MAY LEAD TO MINOR COASTAL  
FLOODING IN LOW-LYING AREAS AROUND HUMBOLDT BAY, CRESCENT CITY AND  
ARENA COVE.  
 
* DRY AND SEASONABLY COOL WEATHER EXPECTED THROUGH FRIDAY, FOLLOWED  
BY A CHANCE OF RAIN OVER THE WEEKEND.  
 
 
   
DISCUSSION  
HIGH PRESSURE IS FORECAST TO REMAIN PARKED OVER THE  
NORTHEASTERN PACIFIC THROUGH FRIDAY. DRY WEATHER IS HIGHLY PROBABLE  
FOR NW CALIFORNIA.  
 
ANOTHER "INSIDER TROUGH" WILL DRIVE SOUTHWARD ACROSS THE GREAT BASIN  
TOWARD SOUTHERN CALIFORNIA THROUGH WEDNESDAY. THIS WILL BRING  
INCREASING HIGH CLOUDS ACROSS THE AREA TODAY. RIDGING STRENGTHENS  
AND UPPER-LEVEL HEIGHTS RISES ACROSS THE PACIFIC NORTHWEST IN THE  
WAKE OF THE "INSIDER TROUGH". STRONGER AND BLUSTERY COASTAL  
NORTHERLY WINDS ARE EXPECTED IN THE WAKE OF THIS TROUGH BY THE  
AFTERNOON. GUSTS AROUND 20-30 MPH ARE FORECAST. EAST- NORTHEAST  
WINDS WILL ALSO DEVELOP LATE TONIGHT INTO WEDNESDAY FOR THE  
HIGHER TERRAIN AND OVER LAKE COUNTY, WHERE GUSTS FROM 30-40 MPH  
WILL BE POSSIBLE OVER THE RIDGES. RIDGE LEVEL GUSTS TO 40-45 MPH  
ARE ON THE LIMBS OF THE DISTRIBUTION (95TH PERCENTILE AND ENSEMBLE  
MAX) OVER THE HIGH MOUNTAIN PEAKS.  
 
CHANCE FOR FROST AROUND HUMBOLDT BAY AREA DECREASES THIS MORNING TO  
AROUND 30% AS ANOTHER SHORTWAVE TROUGH GENERATES MORE CLOUD  
COVER. OFFSHORE FLOW RESUMES TONIGHT INTO WEDNESDAY MORNING AND  
THE CHANCE FOR FROST INCREASES AGAIN TO AROUND 40-80% FOR THE  
HUMBOLDT BAY AREA. CHANCE FOR 32F IN THE NORTH OF HUMBOLDT BAY  
INCREASE TO ABOUT 30-50% WEDNESDAY MORNING. MEANINGFUL CHANCES FOR  
EARLY MORNING FROST FOR THE NORTH COAST IS EXPECTED TO CONTINUE  
THURSDAY MORNING.  
 
THE AIR MASS IS NOT FORECAST TO BE EXCEPTIONALLY COLD NEXT WEEK.  
WITH DEW POINTS IN THE 20S, CALM WINDS IN THE VALLEYS AND CLEAR  
SKIES OVERNIGHT, FROST AND FREEZING TEMPERATURES WILL ONCE AGAIN BE  
A FORECAST CHALLENGE FOR INLAND AREAS THAT HAVE NOT HAD A FREEZE  
YET. COLD WEATHER ADVISORIES FOR WIND CHILL MAY ALSO BE A FACTOR  
WITH WINDS AROUND AROUND 5-10 MPH AND MINIMUM TEMPERATURES IN THE  
LOWER TO MID 30S. FOG AND LOW CLOUDS WILL FORM EACH AND EVERY NIGHT  
(100% CHANCE), THOUGH THE COVERAGE WILL DECREASE AS THE AIR MASS  
SLOWLY DRIES OUT EACH DAY THIS WEEK.  
 
MASSIVE 500MB RIDGE APPEARS TO FLATTEN OUT FRIDAY AND INTO NEXT  
WEEKEND. ALL GLOBAL ENSEMBLE PREDICTION SYSTEMS CONTINUE TO INDICATE  
INCREASING CHANCES FOR 0.10 TO 0.25 INCHES OF RAIN IN 24 HOURS  
THROUGH THE WEEKEND. 24 HOUR CHANCE FOR > 1 INCH IS NO MORE THAN  
20%. IT IS INTERESTING TO NOTE THAT THE MAJORITY OF WPC ENSEMBLE  
CLUSTERS ARE DRIER THAN THE GRAND ENSEMBLE. THE ENSEMBLE MEAN IS BY  
NO STRETCH VERY WET EITHER. IT COULD BE WET OR IT COULD BE DRY OR  
BOTH OVER MULTIPLE DAYS. STAY TUNED.  
 
 
   
AVIATION...(6Z TAFS)  
OFFSHORE FLOW CONTINUES, KEEPING COASTAL  
STRATUS FROM FORMING AND THE TERMINALS LARGELY VFR. INTERIOR  
VALLEYS, INCLUDING UKI, ARE STILL LIKELY TO SEE LIFR STRATUS AND FOG  
AGAIN TONIGHT, BUT WITH SLIGHTLY LOWER CONFIDENCE THAN PREVIOUS  
NIGHTS. ANY CLOUDS ARE LIKELY TO LIFT AND SCATTER BY THE LATE  
MORNING, BRINGING VFR CONDITIONS FOR THE AFTERNOON AND EVENING.  
WINDS AT THE COASTAL AREAS MAY BE BREEZY, ESPECIALLY AROUND CEC,  
WITH GUSTS POTENTIALLY EXCEEDING 20 KTS. JB  
 
 
   
MARINE  
NORTH WINDS ARE FORECAST TO STRENGTHEN AND PUSH CLOSER TO  
THE COAST BY THE AFTERNOON TODAY. GALE FORCE GUSTS UP TO 35 KTS ARE  
POSSIBLE IN THE OUTER WATERS, WITH GUSTS UP 20-25 KTS POSSIBLE  
NEARSHORE. STEEP SEAS COMBINE WITH A LONG PERIOD WNW SWELL THAT HAS  
FILLED IN AND PEAKED AROUND 8-9 FT AT 22 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. JB  
 
 
   
BEACH HAZARDS  
A LONG PERIOD WNW SWELL FILLED IN MONDAY AFTERNOON  
AND PEAKED AT AROUND 7-9 FT AT 22 SECONDS. THE PERIOD HAS DECREASED  
TO 17-18 SECONDS AS OF MONDAY EVENING AND PERIODS WILL CONTINUE TO  
DECREASE THROUGH THE DAY TUESDAY. DESPITE SHORTENING PERIODS  
TUESDAY, HIGH ASTRONOMICAL TIDES CAN INCREASE THE DANGER OF SNEAKER  
WAVES, ESPECIALLY OVER ROCKS AND JETTIES.  
 
SNEAKER WAVES ARE A UNIQUE HAZARD, WITH UP TO 30 MINUTES BETWEEN  
WAVES. LARGE, UNEXPECTED WAVES CAN SWEEP ACROSS THE BEACH WITHOUT  
WARNING, SWEEPING PEOPLE INTO THE SEA FROM ROCKS, JETTIES, AND  
BEACHES. THESE SNEAKER WAVES CAN ALSO MOVE LARGE OBJECTS SUCH AS  
LOGS, CRUSHING ANYONE CAUGHT UNDERNEATH. EVEN ANKLE TO KNEE DEEP  
WATER CAN KNOCK YOU DOWN AND DRAG YOU OUT WHEN A SNEAKER WAVE HITS.  
PAY ATTENTION AND STAY ABOVE THE HIGH WATER LINE AND ANY WET SAND TO  
STAY SAFE. IF THE GROUND IS WET, WAVES HAVE SURGED THERE RECENTLY.  
STAY SAFE AND NEVER TURN YOUR BACK ON THE OCEAN! /JJW/JB  
 
 
   
COASTAL FLOODING  
KING TIDES RETURN ON TUESDAY. HIGH ASTRONOMICAL  
TIDES ARE PREDICTED FROM TUESDAY THROUGH SUNDAY FOR NORTHWEST  
CALIFORNIA. THE COMBINATION OF A HIGH ASTRONOMICAL TIDES, A POSITIVE  
TIDAL ANOMALY, AND A LONG-PERIOD SWELL WILL INCREASE THE RISK OF  
MINOR COASTAL FLOODING AROUND HUMBOLDT BAY, INCLUDING KING SALMON  
AND LOW-LYING ROADS NEAR ARCATA BOTTOMS. /JJW  
 
 
   
EKA WATCHES/WARNINGS/ADVISORIES  
 
CA...  
BEACH HAZARDS STATEMENT UNTIL 10 AM PST THIS MORNING FOR  
CAZ101-103-104-109.  
 
NORTHWEST CALIFORNIA COASTAL WATERS...  
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM PST  
WEDNESDAY FOR PZZ450-455.  
 
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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FOR FORECAST ZONE INFORMATION  
SEE THE FORECAST ZONE MAP ONLINE:  
HTTPS://WWW.WEATHER.GOV/IMAGES/EKA/ZONEMAP.PNG  
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