938  
FXUS66 KEKA 271054  
AFDEKA  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE EUREKA CA  
354 AM PDT TUE SEP 27 2016  
   
SYNOPSIS
 
A GRADUAL COOLING TREND IS EXPECTED TO BEGIN ON  
TUESDAY AS AN UPPER RIDGE DRIFTS SLOWLY EAST THROUGH THE WEEK.  
SOME LIGHT RAIN MAY DEVELOP LATE IN THE WEEK OR OVER THE WEEKEND.  
 

 
   
DISCUSSION
 
OVERNIGHT PICS FROM SPACE SHOWING A GROWING LAYER  
OF STRATUS OFF THE COAST...EVEN MORE THAN WHAT THE VISUAL IMAGERY  
SHOWED YESTERDAY AFTERNOON. SO THE RETURN OF MARINE INFLUENCE  
(CLOUDS AND FOG) SHOULD BE WELL INTACT AS ONSHORE FLOW GAINS  
STRENGTH. THIS AND A GRADUAL COOLING TREND IS IN STORE FOR THE  
NEXT FEW DAYS AS AN UPPER TROUGH DEEPENS OFF THE PACIFIC NORTHWEST  
COAST. 1000-500 MB THICKNESS VALUES WILL DESCEND FROM NEAR 579 DAM  
TO 550 DAM ON FRIDAY. BY FRIDAY, HIGH TEMPERATURES ACROSS THE  
INTERIOR WILL RANGE FROM THE 70S IN THE VALLEYS TO 50S IN THE  
MOUNTAINS WHILE COASTAL AREAS STAY IN THE 60S THROUGHOUT THE WEEK.  
THE UPPER TROUGH WILL BRING INCREASING MOISTURE TO THE REGION  
FRIDAY INTO THE WEEKEND. A CHANCE FOR SOME RAIN SHOWERS OVER THE  
NORTHERN HALF OF THE FORECAST AREA WILL BEGIN FRIDAY AND CONTINUE  
THROUGH SATURDAY AS THE TROUGH MOVES INLAND. SECONDARY SHORTWAVES  
BEHIND THE TROUGH AXIS WILL THEN DIVE SOUTHEAST TOWARD THE PACIFIC  
NORTHWEST AND NORTHWEST CALIFORNIA SUNDAY THROUGH EARLY NEXT WEEK.  
THERE REMAINS VERY HIGH UNCERTAINTY AS TO THE TRAJECTORY AND  
STRENGTH OF EACH OF THESE SHORTWAVES WITH POOR MODEL RUN-TO-RUN  
CONSISTENCY. NONETHELESS THERE STILL LOOKS LIKE A DECENT SHOT OF  
AT LEAST SOME RAIN IN THE NORTHERN HALF OF THE AREA AND THE  
POTENTIAL FOR RAIN TO FALL ACROSS ALL OF NORTHWEST CALIFORNIA AT  
SOME POINT SUNDAY INTO EARLY NEXT WEEK. /RPA/JT  
 

 
   
AVIATION
 
FOG AND LOW CLOUDS HAVE BEEN PRODUCING LIFR CONDITIONS  
AT BOTH KACV AND KCEC THROUGH THE NIGHT. CONDITIONS SHOULD IMPROVE  
SOME BY THIS AFTERNOON AS THE LAND MASS HEATS UP, HOWEVER CONFIDENCE  
IS NOT HIGH THE CLEARING WILL BE COMPLETE OR LAST LONG. NORTHERLY  
WINDS OFFSHORE WILL RESULT IN MORE LOW CLOUD AND FOG GENERATION BY  
THIS EVENING. CONDITIONS WILL DETERIORATE QUICKLY AND VSBYS AND  
CEILINGS MAY FALL BELOW MINIMUMS AGAIN THIS EVENING. VFR WILL  
CONTINUE AT KUKI THROUGH THE PERIOD.  
 

 
   
MARINE
 
ASCAT PASS MONDAY EVENING INDICATED NORTH WINDS AROUND  
20-25 KT ACROSS THE OUTER WATERS. WIND REPORTS FROM THE BUOYS WERE  
NOT AS STRONG. COMBINED SEAS WILL BUILD TO 10 FT TODAY AND REMAIN  
ELEVATED THROUGH WED NIGHT. SMALL CRAFT ADVISORIES FOR BOTH WINDS  
AND COMBINED SEAS ARE IN EFFECT FOR THE OUTER WATERS. NORTH WINDS  
AND SEAS WILL START TO EASE ON THU AND THEN FALL OFF EVEN MORE ON  
FRI AS A FRONT APPROACHES THE OFFSHORE WATERS.  
 

 
   
EKA WATCHES/WARNINGS/ADVISORIES
 
 
CA...NONE.  
NORTHWEST CALIFORNIA COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 9 AM PDT THURSDAY FOR PZZ470-475.  
 

 
 

 
 
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