307  
FXUS66 KEKA 021238  
AFDEKA  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE EUREKA CA  
504 AM PDT WED APR 2 2025  
   
SYNOPSIS
 
FEW ISOLATED SHOWERS CONTINUE TO DIMINISH AS A COLD  
UPPER LOW PROGRESSES SOUTH. CLEARING AND DRYING WILL ALLOW FOR  
SOME COLDER OVERNIGHT LOWS. A SHARP WARMUP WITH BUILDING HIGH  
PRESSURE CAN BE EXPECTED FOR THE END OF THE WEEK, FOLLOWED BY SOME  
RAIN CHANCES.  
 

 
   
DISCUSSION
 
THE AREA OF LOW PRESSURE CONTINUES OFF TO THE SOUTH  
OF NORTHWESTERN CALIFORNIA WITH SOME STRAGGLING SHOWERS CONTINUING  
TO DIMINISH INTO THIS AFTERNOON. THE USUAL POST FRONTAL  
DETERRENTS FOR COLD OVERNIGHT LOWS, SUCH AS LINGERING CLOUD COVER  
AND MOISTURE, AND CHANCE FOR DEVELOPING FOG, FROST AND FREEZE  
CONDITIONS HAVE AND WILL OCCUR IN SOME OF OUR INLAND LOCATIONS  
WHERE THE GROWING SEASON HAS OFFICIALLY BEGUN. A FROST ADVISORY  
AND FREEZE WARNING HAVE BEEN HOISTED FOR INTERIOR MENDOCINO AND  
LAKE COUNTY THROUGH MID MORNING. THERE ARE ALSO FROSTY  
TEMPERATURES OF 36 DEGREES OR LESS FORECAST FOR INTERIOR HUMBOLDT,  
BUT CONFIDENCE IS LOWER THERE FOR THE REASONS OUTLINED ABOVE.  
GROWING SEASON HAS BEGUN FOR INTERIOR HUMBOLDT TODAY, SO IT WILL  
BE CLOSELY WATCHED, AND A FROST ADVISORY MAY BE WARRANTED IF  
DRYING AND CLEARING OCCURS SOONER.  
 
CONFIDENCE IS HIGHER FOR COOLER TEMPS AND FROST/FREEZE CONDITIONS TONIGHT  
AND INTO THURSDAY MORNING. THERE IS MORE CONFIDENCE FOR INTERIOR  
MENDOCINO AND LAKE COUNTIES TO REACH FREEZING/FROST CONDITIONS  
OVERNIGHT AND INTO THURSDAY MORNING. AS A RESULT, A FREEZE  
WARNING HAS BEEN ISSUED FOR NORTHERN INTERIOR MENDOCINO. THEN,  
ALSO, A FROST ADVISORY HAS BEEN ISSUED FOR SOUTHERN INTERIOR  
MENDOCINO AND SOUTHERN LAKE.  
 
A STOUT AREA OF HIGH PRESSURE WILL THEN AMPLIFY INTO THE AREA BY  
FRIDAY AND THROUGH THE WEEKEND. TEMPERATURES WILL WARM UP NICELY  
IN RESPONSE. THE APEX OF THE WARMING WILL BE SATURDAY, WHEN LOW TO  
MID 60S ARE FORECAST FOR THE COAST, AND LOW TO MID 70S FOR THE  
INTERIOR VALLEYS. RAIN CHANCES INCREASE LATE SATURDAY AND SUNDAY  
FROM A CLIPPING WEATHER SYSTEM. IF CLOUDCOVER ARRIVES EARLIER ON  
SATURDAY, TEMPERATURES MAY BE HELD DOWN A BIT.  
 
CURRENTLY, RAINFALL LOOKS LIGHT WITH THIS SYSTEM, WITH THE  
PROBABILITY OF 24 HOUR RAINFALL OVER 0.50 INCH 40-60% FOR THE  
HUMBOLDT THROUGH DEL NORTE SUNDAY AND MONDAY.THERE MAY BE SOME  
INCREASED SOUTHERLY WINDS, ESPECIALLY IF THE LOW TAKES A MORE  
SOUTHERLY TRACK. THERE ARE CURRENTLY LOW PROBABILITIES FOR WIND  
GUSTS OVER 25 MPH. /JJW  
 

 
   
AVIATION
 
WINDS EFFECTIVELY DECOUPLED OVERNIGHT, KEEPING ALL  
TERMINALS VFR OVERNIGHT BENEATH BROKEN MID-LEVEL CEILINGS AND LIGHT  
NE FLOW. LLWS IS STILL PREVALENT FOR UKI AS WINDS ALOFT REMAIN  
ELEVATED THROUGH THE MORNING HOURS - OTHERWISE, THE RUSSIAN RIVER  
VALLEY HAS SO FAR AVOIDED LOW LEVEL CLOUDS/FOG. HI-RES MODELS ARE  
COINCIDING WELL WITH AN OBSERVABLE LINE OF SCATTERED SHOWERS  
APPROACHING THE COAST ON THE BACKSIDE OF A COLD UPPER TROUGH.  
PERIODS OF GUSTY RAIN SHOWERS ARE POSSIBLE AT BOTH CEC AND ACV  
THROUGH MIDDAY, MOVING FROM NORTH TO SOUTH. WIDESPREAD GUSTY NW  
WINDS ARE EXPECTED TO RESUME THIS AFTERNOON AS A HIGH PRESSURE RIDGE  
BUILDS INTO THE EASTERN PACIFIC, TIGHTENING THE COASTAL PRESSURE  
GRADIENT. HIGH PROBABILITIES FOR GUSTS 10 TO 20 KNOTS EXPECTED AT  
ALL TERMINALS THROUGH THIS EVENING, WITH LOCALLY HIGHER GUSTS  
LINGERING A BIT LONGER AT CEC. DRIER NORTHERLY FLOW WILL KEEP THE  
MARINE LAYER AT BAY THROUGH THE END OF THE WEEK.  
 

 
   
MARINE
 
SMALL CRAFT CONDITIONS WITH STEEP NORTHERLY WIND WAVES  
CONTINUE ACROSS THE WATERS AS A NW SWELL DECAYS. MODERATE NORTHERLY  
BREEZES WILL KEEP SEAS ELEVATED THROUGH THE END OF THE WEEK AS A  
HIGH PRESSURE RIDGE BUILDS INTO THE EASTERN PACIFIC. PROBABILITIES  
FOR GUSTS 25 TO 30 KNOTS WILL REMAIN HIGHEST IN THE OUTER WATERS AND  
DOWNWIND OF CAPE MENDOCINO - NBM HAS A 20 TO 40% CHANCE OF GUSTS  
REACHING 34 KNOTS ON THURSDAY EVENING. DIURNAL INCREASES IN WINDS  
WILL LIKELY PUSH ELEVATED SEAS FURTHER INTO THE INNER WATERS EACH  
AFTERNOON. WINDS AND SEAS DIMINISH SIGNIFICANTLY BY FRIDAY AND  
SATURDAY. POTENTIAL FOR ANOTHER FRONTAL SYSTEM TO ARRIVE SUNDAY AS A  
LARGE LONG PERIOD SWELL FILLS INTO THE WATERS. PREVIOUSLY CALM  
CONDITIONS MAY POSE A SNEAKER WAVE THREAT AS THIS SWELL ARRIVES.  
 

 
   
EKA WATCHES/WARNINGS/ADVISORIES
 
 
CA...  
FREEZE WARNING UNTIL 9 AM PDT THIS MORNING FOR CAZ110-111-  
114.  
 
FREEZE WARNING FROM 2 AM TO 9 AM PDT THURSDAY FOR CAZ110-  
111.  
 
FROST ADVISORY FROM 2 AM TO 9 AM PDT THURSDAY FOR CAZ112-  
113-115.  
 
FROST ADVISORY UNTIL 9 AM PDT THIS MORNING FOR CAZ113-115.  
 
NORTHWEST CALIFORNIA COASTAL WATERS...  
SMALL CRAFT ADVISORY UNTIL 9 AM PDT THIS MORNING FOR PZZ450.  
 
SMALL CRAFT ADVISORY UNTIL 9 AM PDT THURSDAY FOR PZZ455.  
 
SMALL CRAFT ADVISORY UNTIL 3 AM PDT FRIDAY FOR PZZ470-475.  
 

 
 

 
 
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