006  
FXUS66 KEKA 252132  
AFDEKA  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE EUREKA CA  
232 PM PDT MON OCT 25 2021  
   
SYNOPSIS
 
SCATTERED SHOWERS WILL SPREAD EAST ACROSS NORTHWEST  
CALIFORNIA THROUGH WEDNESDAY. WARMER AND DRIER CONDITIONS ARE THEN  
EXPECTED ON THURSDAY, FOLLOWED BY ADDITIONAL SHOWER DEVELOPMENT ON  
FRIDAY AND SATURDAY.  
 

 
   
DISCUSSION
 
ONSHORE DEEP-LAYER WESTERLIES COMBINED WITH  
AFTERNOON SURFACE HEATING/DESTABILIZATION WAS AIDING IN THE  
DEVELOPMENT OF ISOLATED POST FRONTAL SHOWER DEVELOPMENT OVER THE  
INTERIOR MOUNTAINS/RIDGES OF NORTHWEST CALIFORNIA. SHOWER  
DEVELOPMENT IS FORECAST TO BECOME MORE WIDESPREAD ACROSS BOTH  
COASTAL AND INLAND AREAS DURING TUESDAY AS A FRONTAL WAVE MOVES  
ACROSS THE REGION. RAINFALL ASSOCIATED WITH THE FRONT WILL BE  
BENEFICIAL IN NATURE. OTHERWISE, DRIER WEATHER WILL BECOME  
PROBABLE DURING MID WEEK. IN ADDITION, LOW-LEVEL WINDS ARE  
FORECAST TO VEER TO NORTHERLY DURING THURSDAY, WHICH WILL BE A  
FLOW REGIME SUPPORTIVE OF WARMER TEMPERATURES, PARTICULARLY ACROSS  
INLAND VALLEYS, WHERE HIGHS IN THE 70S ARE EXPECTED.  
 
NON-ZERO RAIN CHANCES RE-ENTER THE REGION ON FRIDAY AND SATURDAY  
AS A WEAK UPPER WAVE MEANDERS OVER THE REGION. HOWEVER, ANY  
RAINFALL OCCURRING WITH THAT FEATURE IS CURRENTLY FORECAST TO BE  
VERY LIGHT.  
 
GARNER  
 

 
   
AVIATION
 
THROUGH TODAY, ISOLATED VICINITY SHOWERS BECAME MORE  
SCATTERED IN COVERAGE. CIGS HELD TO MOSTLY MVFR, WHILE VIS BRIEFLY  
CAME DOWN TO IFR WITH SOME OF THE BETTER PRECIPITATION RATES.  
OVERNIGHT, SHOWERS WILL BECOME MORE CONSOLIDATED IN COVERAGE TO  
MORE STEADY LIGHT RAIN AT TIMES, AND CIGS WILL FAVOR IFR. SIMILAR  
CONDITIONS WILL BE FOR KUKI, BUT DELAYED TO EARLY TOMORROW  
MORNING. SOUTHEAST WINDS WILL PICK UP OVERNIGHT AS WELL, AND  
BECOME GUSTY AT THE SURFACE. A STRONGER JET OF SOUTH WINDS ALOFT  
WILL BRIEFLY CLIP COASTAL TERMINALS BY EARLY TOMORROW MORNING, UP  
TO 45KTS NEAR 2000 FEET AGL, PROVIDING ENOUGH LLWS FOR PLACEMENT  
IN THE TAFS.  
 

 
   
MARINE
 
WEST SWELL PEAKED AROUND 30 FEET AT 17 SECONDS LAST  
NIGHT. THE SWELL HAS STEADILY SUBSIDED TO AROUND 20 FEET THIS  
AFTERNOON. EVEN THOUGH SWELL HEIGHTS WILL SLOWLY DECAY DURING THE  
NEXT 36 HOURS, SEAS WILL BECOME STEEPER AS SWELL PERIODS DECREASE.  
ALSO, SHORT PERIOD WIND WAVES WILL BUILD NORTH OF CAPE MENDO AS  
SOUTHERLY WINDS INCREASE WITH THE APPROACH OF A FRONT. A LOW  
DURATION (2 TO 4 HOURS) GALE IS POSSIBLE NORTH OF CAPE MENDO  
DURING THE MORNING. SEAS WILL LAY DOWN SOME WEDNESDAY MORNING,  
HOWEVER A REINFORCING WESTERLY SWELL WILL BUILD BY THE EVENING AND  
SEAS WILL BECOME ELEVATED AGAIN. POTENTIAL FOR STRONG NORTHERLIES  
WILL INCREASE ACROSS THE OUTER WATERS BY FRIDAY EVENING.  
 

 
   
HYDROLOGY
 
HEAVY RAINFALL IS NOT EXPECTED DURING THE NEXT SEVEN  
DAYS. AREA RIVERS WILL CONTINUE TO RECEDE AS A RESULT.  
 

 
   
BEACH HAZARDS
 
A WEST SWELL PEAKED AROUND 30 FEET AT 17 SECONDS  
LAST NIGHT. THE SWELL HAS SINCE SUBSIDED TO AROUND 20 FT AT 17  
SECONDS THIS AFTERNOON AND SHOULD CONTINUE ON A GENERAL DOWNWARD  
TREND THIS EVENING AND OVERNIGHT. TO MAINTAIN CONSISTENT MESSAGING  
AND COORDINATION WITH NEIGHBORING OFFICES, WE WILL CONTINUE WITH  
THE SURF WARNING THROUGH THIS EVENING.  
 

 
   
EKA WATCHES/WARNINGS/ADVISORIES
 
 
CA...  
HIGH SURF WARNING UNTIL 11 PM PDT THIS EVENING FOR CAZ101-  
103-104-109.  
 
NORTHWEST CALIFORNIA COASTAL WATERS...  
HAZARDOUS SEAS WARNING UNTIL 9 AM PDT TUESDAY FOR PZZ450-  
455-470-475.  
 

 
 

 
 
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