762  
FXUS66 KEKA 071201  
AFDEKA  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE EUREKA CA  
501 AM PDT TUE JUL 7 2020  
   
SYNOPSIS
 
NEAR NORMAL TEMPERATURES ARE EXPECTED IN THE INTERIOR  
THROUGH THE WEEK. MARINE AIR AND ONSHORE BREEZES WILL KEEP COASTAL  
AREAS SEASONABLY COOL.  
 

 
   
DISCUSSION
 
HIGH PRESSURE WILL BUILD TOWARD THE COAST TODAY IN THE  
WAKE OF A SHORTWAVE TROUGH THAT PRODUCED A DEEP MARINE LAYER AND  
A SHARP DROP IN HIGH TEMPERATURES ACROSS THE INTERIOR YESTERDAY.  
BRISK AND GUSTY NORTH-NORTHWESTERLY WINDS ARE EXPECTED FOR THE  
COASTAL AREAS LATER TODAY AND AGAIN ON WEDNESDAY. CLOUD COVER  
WILL ALSO BE LESS. BREEZY WESTERLY TO NORTHWESTERLY CONDITIONS  
ARE ALSO EXPECTED IN THE INTERIOR, HOWEVER RELATIVE HUMIDITIES  
HAVE BEEN TRENDING UPWARD OVERNIGHT AT MANY REPORTING STATIONS IN  
THE INTERIOR.  
 
A BROAD UPPER LEVEL TROUGH WILL REMAIN OVER THE AREA THROUGH MID  
WEEK. TEMPERATURES IN THE INTERIOR WILL GENERALLY EDGE UPWARD  
THROUGH THE WEEK AS THE TROUGH SLOWLY LIFTS NORTHWARD. ONSHORE  
BREEZES WILL LIKELY KEEP MOST INTERIOR TEMPERATURES NEAR OR  
SLIGHTLY ABOVE NORMAL. A STRONG UPPER RIDGE CENTERED OVER THE  
FOUR CORNERS REGION WILL EXPAND SLIGHTLY WESTWARD LATE IN THE  
WEEK. ANOTHER TRANSIENT TROUGH WILL PROBABLY KNOCK THE RIDGE DOWN  
OVER THE WEEKEND AND TEMPERATURES SHOULD NOT WARM TO EXTREME  
LEVELS, 105-110F, IN THE INTERIOR. ENSEMBLE GUIDANCE, NAMELY THE  
GEFS PLUMES, INDICATE LARGER SPREADS IN 850MB TEMPERATURES NEXT  
WEEK. EPS AND CMCE MEANS WERE SLIGHTLY WARMER COMPARED TO THE GEFS  
MEAN.  
 

 
   
AVIATION
 
OVERNIGHT, THE MARINE LAYER CONTINUED TO DEEPEN IN  
RESPONSE TO UPPER-LEVEL TROUGHING PASSING BY. OBSERVATIONS AND  
PROFILE IMAGERY REVEALED THE LAYER REACHED OVER 3,500 FEET IN DEPTH.  
THROUGH THE EARLY MORNING HOURS, THE COASTAL TERMINAL HELD VFR  
CONDITIONS WHILE STRATUS LOOMED IN THE VICINITIES OF KCEC AND KACV.  
VFR GAVE WAY TO PERIODS OF LIFR CEILINGS AS THE STRATUS FILLED BACK  
IN. HIGH PRESSURE RIDGING WILL BEGIN BUILDING IN TODAY, ACTING TO  
COMPRESS THE MARINE LAYER SOMEWHAT. IMPROVEMENT IS EXPECTED TOMORROW  
DURING TYPICAL DIURNAL TRENDS; HOWEVER, THE LAYER WILL STILL BE DEEP  
ENOUGH TO POTENTIALLY DELAY THIS. THE MARINE LAYER WILL REMAIN  
THREATENING CLOSE TO SHORE TODAY, POTENTIALLY BREACHING THE COAST AT  
TIMES BEFORE EVENTUAL COMPLETE RESURGENCE INTO THE EVENING.  
/JJW  
 

 
   
MARINE
 
THE WATERS HAVE HELD A PERSISTENT PATTERN OF A MODERATE  
NORTHERLY WIND REGIME, FOCUSED ON THE LEE SIDE OF CAPE MENDOCINO.  
WITH THE PASSING OF AN UPPER-TROUGH, THE PATTERN WILL SHIFT WITH A  
TEMPORARY RIDGE BUILDING IN BEHIND IT. IN RESPONSE, THE PRESSURE  
GRADIENT WILL TIGHTEN UP AND ALLOW THE STRONGER WINDS TO EXPAND INTO  
THE NORTHERN OUTER WATERS BEGINNING THIS AFTERNOON, AND REACHING  
SMALL CRAFT ADVISORY LEVELS INTO THE EVENING. AS IS TYPICAL ON THE  
LEE SIDE OF CAPE MENDOCINO, WINDS WILL ACCELERATE WITH SOME LOCAL  
GUSTS APPROACHING GALE FORCE POSSIBLE IN THE AFTERNOONS AND EVENINGS  
THROUGH WEDNESDAY. STEEP SEAS WILL GENERALLY BUILD TO 7 FEET IN THE  
OUTER WATERS, WITH 8 TO 9 FEET IN ISOLATED AREAS SOUTH OF THE CAPE.  
 
THE NORTHERLY WIND REGIME WILL PERSIST LATER INTO THE WEEK. HOWEVER,  
WITH ANOTHER TROUGH OF LOW PRESSURE PASSING BY TO OUR NORTH, THE  
PRESSURE GRADIENT AND CORRESPONDING NORTHERLY WINDS WILL EASE BACK  
AGAIN TO THE NORTH OF CAPE MENDOCINO. THIS SHOULD ALLOW FOR LOWER  
SEAS ACROSS OUR WATERS AS WELL, BUT CONDITIONS WILL REMAIN LOCALLY  
ROUGH TO THE LEE OF CAPE MENDOCINO. JJW/AAD  
 

 
   
EKA WATCHES/WARNINGS/ADVISORIES
 
 
CA...NONE.  
NORTHWEST CALIFORNIA COASTAL WATERS...  
SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 3 AM PDT  
THURSDAY FOR PZZ470. SMALL CRAFT ADVISORY UNTIL 9 PM PDT  
WEDNESDAY FOR PZZ455. SMALL CRAFT ADVISORY UNTIL 3 AM PDT  
THURSDAY FOR PZZ475.  
 

 
 

 
 
VISIT US AT HTTPS://WWW.WEATHER.GOV/EUREKA  
 
FOLLOW US ON FACEBOOK AND TWITTER AT:  
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  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab CA Page Main Text Page