650  
FXUS66 KEKA 102017  
AFDEKA  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE EUREKA CA  
117 PM PDT TUE JUN 10 2025  
   
SYNOPSIS  
ISOLATED THUNDERSTORMS TRINITY COUNTY THROUGH THIS  
EVENING. INTERIOR TEMPERATURES FORECAST TO DIMINISH EACH DAY  
THROUGH FRIDAY.  
 
 
 
KEY MESSAGES:  
 
* ISOLATED THUNDERSTORMS TRINITY COUNTY THROUGH THIS EVENING.  
STRONG OUTFLOW WIND GUSTS FROM STORMS POSSIBLE.  
 
* INTERIOR HEAT RISK DIMINISHING AND BECOMING LOW FOR THE  
REMAINDER OF THIS WEEK.  
 
* GUSTIER WESTERLY AND NORTHWESTERLY BREEZES IN THE INTERIOR  
VALLEYS EACH AFTERNOON AND EVENING WEDNESDAY THROUGH SATURDAY.  
 
* STRENGTHENING COASTAL NORTHERLIES MID TO LATE WEEK.  
 
 
   
DISCUSSION  
 
AN UPPER LEVEL RIDGE OVER CALIFORNIA WILL MIGRATE EASTWARD AS A WEAK  
UPPER LEVEL TROUGH SWINGS OVER OUR AREA FROM THE NORTH. THIS  
SYNOPTIC WEATHER CHANGE WILL AD VARIETY TO OUR DAILY WEATHER. FIRST  
AND FOREMOST, THERE IS CAPE ALOFT OVER THE KLAMATH MOUNTAINS,  
ALLOWING FOR DAYTIME HEATING TO POP INTO THUNDERSTORMS FOR ONE MORE  
AFTERNOON. THE GFS IS SHOWING "MOST UNSTABLE CAPE" VALUES CENTERED  
OVER DEL NORTE, TRINITY, AND NORTHEASTERN MENDOCINO COUNTY TUESDAY  
NIGHT. BRIEF WETTING RAIN, CLOUD TO GROUND LIGHTING, AND SMALL (PEA-  
SIZED) HAIL IS POSSIBLE WITH THESE STORMS. UPPER LEVEL VORTICITY  
WILL BE PRESENT IN THE 700MB LEVEL WHICH COULD HELP SUSTAIN SOME  
THUNDERSTORM BRIEFLY. HOWEVER, THE STORMS LOOK RELATIVELY DRY WITH  
THE TROPOSPHERE BEING AT 46% RH BY 00Z/5PM.  
 
TUESDAY HAS A DECREASED CHANCE IN THE NBM PROBABILITY FOR THUNDER  
WITH THE TRINITY HORN AREA HAVING A 10-20% CHANCE OF THUNDERSTORMS.  
DEL NORTE AND NE MENDOCINO SHOW ONLY A 0-5% CHANCE SO CONFIDENCE  
REMAINS LOW FOR STORMS DEVELOPING IN THOSE AREAS. THE MAJORITY OF  
THE CONVECTIVE DEVELOPMENT LOOKS TO STAY MUCH FURTHER EAST OF CWA IN  
SOUTHERN OR AND NE CA. POTENTIAL FOR GUSTY WINDS AND DRY LIGHTNING  
COULD BE A FIRE WEATHER CONCERN FOR THESE AREAS. THIS INCOMING  
TROUGH LOOKS QUITE DRY AND MAIN IMPACTS APPEAR TO BE A RETURN OF  
STRONGER GUSTY WINDS AND COOLER TEMPERATURES.  
 
INLAND VALLEYS WILL STRUGGLE TO BREAK 90F ON WEDNESDAY THROUGH THE  
REST OF THE WEEK AND WEEKEND. HIGH TEMPERTURES LOOK TO BE AROUND THE  
LOW 80S AT THE WARMEST FOR INLAND VALLEYS FRIDAY AND SATURDAY AS OF  
RIGHT NOW. THIS COMES A RELIEF AFTER WHAT HAS BEEN A WARM COUPLE OF  
WEEKS TO START METEOROLOGICAL SUMMER. THESE COOLER TEMPERATURES WILL  
ALSO BE ACCOMPANIED BY STRONGER WINDS WITH AFTERNOON WIND GUSTS  
AROUND 15-20MPH IN THE LATER PORTION OF THE WEEK.  
 
 
   
AVIATION  
 
10/18Z TAFS...IFR CEILINGS ALONG THE COASTAL TERMINALS WITH A  
STRONG LOW LEVEL INVERSION EARLY THIS AFTERNOON. STRATUS WILL  
CONTINUE TO ERODE BACK TO THE COAST WITH THE DIURNAL HEATING.  
HOWEVER, MAINLY IFR CEILINGS ARE EXPECTED TO PERSIST AT ACV AND  
CEC WITH SMALL SCALE CYCLONIC EDDIES ALONG THE COAST KEEPING THE  
SHORELINE WITH LOW CLOUDS MOVING IN AND OUT. LIFR CONDITIONS ARE  
FORECAST TO REDEVELOP THIS EVENING AND TONIGHT, WITH CEILING  
AROUND FL002-FL004 AND VISIBILITY IN MIST/FOG. HREF MODEL GUIDANCE  
FOR VISIBILITY SUGGEST THERE IS A 20% CHANCE OF AT LEAST 0.5SM OR  
LESS OVERNIGHT AT BOTH COASTAL TERMINALS. MEANWHILE, PREVAILING  
VFR CONDITIONS AT UKI. SURFACE WINDS GENERALLY OUT OF WSW AT 5-10  
KTS AT ALL TAF TERMINALS, WITH SOME OCCASIONAL GUSTS UP TO 15KT AT  
UKI.  
 
 
   
MARINE  
 
GENTLE TO MODERATE NORTHERLY BREEZES CONTINUE TO SPREAD ACROSS  
THE COASTAL WATERS TODAY. WINDS WILL CONTINUE TO GRADUALLY INCREASE  
ACROSS THE OUTER WATERS THROUGH THE WORK WEEK. LOCALLY NEAR GALE  
TO GALE FORCE WIND GUSTS IS FORECAST TO DEVELOP LEEWARD OF CAPE  
MENDOCINO WEDNESDAY AFTERNOON. WIDESPREAD FRESH TO STRONG NORTHERLY  
BREEZES WITH SOME NEAR GALE FORCE GUSTS DOWNWIND OF CAPE MENDOCINO  
BEGINS ON THURSDAY AND THEN CONTINUES INTO THE WEEKEND AS THE  
HIGH PRESSURE STALLS OVER THE EASTERN PACIFIC AND THE PRESSURE  
GRADIENT TIGHTENS UP ALONG THE COAST.  
 
MID PERIOD NORTHWEST SWELL WILL CONTINUE TO DOMINATE THE SEA  
STATE THROUGH MID WEEK. IN ADDITION, A LONG PERIOD SOUTHWEST SWELL  
OF 3-4 FEET AT 17 SECONDS WILL SLOWLY SUBSIDE THROUGH THURSDAY.  
THIS COULD PRESENT A SMALL SNEAKER WAVE THREAT ON SOUTH FACING  
BEACHES IF IT ENDS UP COMING IN THIS BIG. WIND DRIVEN SEAS ARE  
EXPECTED TO INCREASE ON THURSDAY AND FRIDAY.  
 
 
   
EKA WATCHES/WARNINGS/ADVISORIES  
 
CA...  
NONE.  
NORTHWEST CALIFORNIA COASTAL WATERS...  
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 9 PM PDT  
WEDNESDAY FOR PZZ475.  
 
 
 
 
 
NOTE: THE FULL FORECAST DISCUSSION IS NOW REGULARLY ISSUED BETWEEN  
10 AM/PM AND 1 PM/AM. ADDITIONAL UPDATES WILL BE ISSUED AS NEEDED.  
 
VISIT US AT HTTPS://WWW.WEATHER.GOV/EUREKA  
 
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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  
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