224  
FXUS66 KEKA 311106  
AFDEKA  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE EUREKA CA  
406 AM PDT FRI OCT 31 2014  
   
SYNOPSIS
 
A COLD FRONT IS MOVING ACROSS THE REGION THIS MORNING  
BRINGING RAIN. BEHIND THE FRONT THERE WILL BE A BREAK IN THE RAIN  
BEFORE SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS MOVE INTO THE  
AREA THIS AFTERNOON AND TONIGHT. SHOWERS WILL TAPER OFF SATURDAY  
AS HIGH PRESSURE BUILDS INTO THE AREA FOR A FEW DAYS.  
 

 
   
SHORT TERM
 
A COLD FRONT MOVING ONSHORE THIS MORNING IS BRINGING  
PERIODS OF HEAVY RAIN. WINDS ARE IN THE 10 TO 20 MPH AT THE  
SURFACE SO THE RAINFALL AMOUNTS ARE MORE CONSISTENT OVER THE AREA  
THAN WITH STRONGER WINDS AND UPSLOPE/DOWNSLOPE EFFECTS. IR SAT  
SHOWS THE BACK EDGE OF THE CLOUDS ASSOCIATED WITH THE FRONT ABOUT  
50 MILES OFFSHORE. MODELS ARE INDICATING A DRY SLOT WILL MOVE ONTO  
THE COAST AROUND SUNRISE NORTH OF CAPE MENDOCINO AND SLOWLY SPREAD  
SOUTH AND EAST THROUGH THE MORNING.. THERE WILL LIKELY BE A  
FAIRLY DECENT BREAK IN THE RAIN ASSOCIATED WITH THIS DRY SLOT.  
 
THE HRRR MODEL IS INDICATING SOME SHOWERS THIS AFTERNOON...BUT  
THE NAM AND GFS ARE NOT SHOWING MUCH INSTABILITY OR QPF SO THE  
SHOWERS MAY BE WEAKER THAN PREVIOUSLY THOUGHT. LEFT THE SLIGHT  
CHANCE OF THUNDERSTORMS AND SMALL HAIL IN THE FORECAST FOR THIS  
AFTERNOON AND EVENING AS THE IR SAT SHOWING THE TROUGH OFFSHORE  
HAS FAIRLY COLD CLOUD TOPS. AROUND -45C IN THE STRONGEST SHOWERS  
TO THE WEST OF US. SNOW LEVELS WITH THESE SHOWERS WILL DROP AS LOW  
AS 4500 FT TONIGHT AND THIS MAY BRING A FEW INCHES OF SNOW.  
 
TONIGHT AND SATURDAY SHOWERS WILL REMAIN SCATTERED OVER THE AREA.  
THERE MAY BE SOME PERIODS OF HEAVIER SHOWERS AS SOME VORT MAXES  
ROTATE AROUND THE BOTTOM OF THE TROUGH. AT THIS POINT IT IS  
DIFFICULT TO PINPOINT THE TIMING OF THESE SHORTWAVES. THERE DOES  
APPEAR TO BE A BIT OF VORT MAX ON THE BACKSIDE OF THE TROUGH AS IT  
MOVES THROUGH SATURDAY AFTERNOON. THIS COULD ENHANCE SHOWERS A  
BIT...ALTHOUGH ONLY ECMWF HAS SOME QPF DURING THIS TIME.  
 
SATURDAY NIGHT INTO SUNDAY A RIDGE OF HIGH PRESSURE STARTS TO  
BUILD INTO THE AREA WHICH WILL PUT AN END TO THE SHOWERS. THIS  
WILL LIKELY ALLOW FOG AND LOW CLOUDS TO DEVELOP OVER THE INLAND  
VALLEYS DUE TO THE RECENT RAINS. ANY AREAS THAT MANAGE TO REMAIN  
CLEAR WILL LIKELY SEE SOME FROST. HIGHS ACROSS THE AREA WILL  
LIKELY REBOUND INTO THE 60S IN MOST AREAS WITH COOLER TEMPERATURES  
AT HIGHER ELEVATIONS. THE INLAND VALLEYS MAY BE A BIT SLOW TO  
CLEAR OUT AND THIS COULD KEEP TEMPERATURES A BIT COOLER THERE.  
SUNDAY NIGHT INTO MONDAY MORNING APPEARS TO HAVE A BETTER CHANCE  
FOR FROST...HOWEVER ONCE AGAIN THERE MAY BE QUITE A BIT OF LOW  
LEVEL MOISTURE AROUND. THIS WILL NEED TO BE WATCHED AS IT GETS  
CLOSER. MONDAY MODELS ARE SHOWING A WARM FRONT MOVING ACROSS THE  
AREA AND BRINGING SOME CLOUDS. THIS WILL ALSO INHIBIT COOLING IN  
THE NORTHERN AREAS. FOR NOW ANY RAINFALL LOOKS TO BE CONFINED TO  
DEL NORTE COUNTY AS THE FRONT STALLS OUT...BUT CONFIDENCE IS LOW  
ON THE EXACT LOCATION WHERE THE FRONT STALLS OUT. MKK  
 

 
   
AVIATION
 
MODERATE RAIN ASSOCIATED WITH THE COLD FRONT MOVING  
THROUGH IS CONTINUING ACROSS MUCH OF THE AREA BRINGING MVFR TO IFR  
CONDITIONS. THIS WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST THIS  
MORNING. LATE THIS MORNING INTO THE AFTERNOON SHOWERS WILL START  
TO DEVELOP ACROSS THE AREA. THERE ARE STILL SOME QUESTIONS ON THE  
STRENGTH AND COVERAGE OF THESE SHOWERS...BUT IT LOOKS LIKE THERE  
IS A SLIGHT CHANCE FOR THUNDER THIS AFTERNOON AND EVENING. MAINLY  
VFR CONDITIONS ARE EXPECTED THIS AFTERNOON WITH LOCAL IFR  
CONDITIONS IN THE HEAVIER SHOWERS. SHOWERS WILL CONTINUE  
OVERNIGHT...BUT ARE EXPECTED TO WEAKEN AND THE THREAT FOR THUNDER  
WILL DIMINISH. MKK  
   
LONG TERM
 
PER THE PREVIOUS DISCUSSION, KEPT THE LONG TERM  
FORECAST MOSTLY UNCHANGED WITH MINIMAL NUDGES IN THE POP GRIDS,  
MAINLY TO MATCH OUR NEIGHBORS. OTHERWISE, POPULATED WITH THE  
CONSMODEL FOR MOST OF THE GRIDS.  
 

 
   
MARINE
 
THE MORNING BUOY OBSERVATIONS SHOW A MODERATE TO FRESH  
BREEZE WITH WAVE HEIGHTS RANGING FROM 4-5 FT. THE 0415Z ASCAT PASS  
SHOWED AN AREA OF STRONGER WINDS JUST AHEAD OF THE COLD FRONT.  
CONSIDERING THE EASTWARD MOVEMENT OF THE FRONT, THIS MATCHES WELL  
WITH WHAT THE BUOYS ARE CURRENTLY REPORTING. THE GUSTY WINDS WILL  
CONTINUE EARLY THIS MORNING AS THE COLD FRONT CROSSES OUR WATERS.  
WINDS WILL SHIFT TO THE NORTHWEST BY TONIGHT AS THE FRONT MOVES  
INLAND, THEN REMAIN LIGHT TO MODERATE THROUGH THE WEEKEND. THE  
STRONGEST WINDS ARE EXPECTED TO BE SOUTH OF CAPE MENDOCINO WHERE THE  
SURFACE PRESSURE GRADIENT WILL BE STRONGER. AS FOR SEAS, THEY WILL  
BUILD TODAY AS A POST-FRONTAL SWELL ENTERS THE WATERS. LEFT THE  
SC.Y'S UNCHANGED. SEAS ARE EXPECTED TO SUBSIDE ON SUNDAY THEN BUILD  
AGAIN EARLY NEXT WEEK AS ANOTHER SWELL MOVES THROUGH THE WATERS.  
 

 
   
EKA WATCHES/WARNINGS/ADVISORIES
 
 
CA...NONE.  
NORTHWEST CALIFORNIA COASTAL WATERS...  
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM PDT  
SATURDAY FOR PZZ450-470.  
 
SMALL CRAFT ADVISORY FROM 3 PM PDT THIS AFTERNOON TO 2 AM PST  
SUNDAY FOR PZZ455-475.  
 

 
 

 
 
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