286  
FXUS66 KEKA 252211  
AFDEKA  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE EUREKA CA  
311 PM PDT SUN JUN 25 2017  
   
SYNOPSIS
 
ISOLATED THUNDERSTORMS WILL CONTINUE THROUGH THE  
REMAINDER OF THE AFTERNOON ACROSS PORTIONS OF THE MOUNTAINOUS  
INTERIOR...PARTICULARLY TRINITY COUNTY. THIS WILL AGAIN BE  
POSSIBLE NEAR THE TRINITY HORN TOMORROW AND TUESDAY AFTERNOON. HOT  
TEMPERATURES WILL COOL BACK TO NEAR NORMAL VALUES TOMORROW THROUGH  
THE REMAINDER OF THE WEEK.  
 

 
   
DISCUSSION
 
AFTER SEVERAL DAYS IN A ROW OF WELL ABOVE NORMAL  
TEMPERATURES THROUGHOUT THE AREA, A PATTERN SHIFT IS UNDERWAY THAT  
WILL PROVIDE RELIEF FOR A LARGE PORTION OF NORTHWEST CALIFORNIA.  
JUST OFFSHORE AN UPPER LEVEL LOW PRESSURE SYSTEM IS SLOWLY  
APPROACHING THE COAST, AND AS A RESULT, THE UPPER LEVEL RIDGE THAT  
HAS PERSISTED ALONG THE WEST COAST IS BEGINNING TO WEAKEN.  
TEMPERATURES TODAY WILL END UP FALLING ONLY A FEW DEGREES COOLER  
THAN PREVIOUS DAYS, BUT MONDAY AND BEYOND WILL SEE HIGH  
TEMPERATURES FALL INTO THE 80S AND 90S...A BIT MORE TOLERABLE AND  
CLOSER TO NORMAL. MEANWHILE ALONG THE COAST, A STEADILY DEEPENING  
MARINE LAYER HAS ALLOWED STRATUS TO MOVE FARTHER INTO COASTAL  
VALLEYS, AND HAS PERSISTED MUCH OF THE AFTERNOON IN MANY AREAS.  
THIS IS EXPECTED TO CONTINUE FOR THE NEXT SEVERAL DAYS, WITH  
CLOUDY DRIZZLY NIGHTS AND A SLOW DISSIPATION OF CLOUDS DURING THE  
LATE MORNING AND AFTERNOON HOURS.  
 
AS FOR THUNDERSTORMS, THE PREVIOUSLY MENTIONED UPPER LOW HAS  
BROUGHT SOUTHERLY FLOW AND INCREASED MID-LEVEL MOISTURE TO THE  
REGION. AS A RESULT, THUNDERSTORMS HAVE BEGUN TO FIRE EARLY THIS  
MORNING ACROSS SISKIYOU COUNTY, AND AS OF 3 PM ARE BEGINNING TO  
DEVELOP ACROSS PARTS OF TRINITY COUNTY AS WELL. THESE SHOWERS WILL  
LIKELY BE CAPABLE OF PRODUCING CLOUD TO GROUND LIGHTNING STRIKES  
AND PERHAPS SOME GUSTY WINDS. HOWEVER, DRY SUB-CLOUD LAYERS WILL  
LIKELY RESULT IN SIGNIFICANT RAINFALL EVAPORATION, AND MANY  
VALLEYS WILL NOT LIKELY SEE MUCH RAIN IF ANY. THUNDERSTORMS WILL  
AGAIN BE POSSIBLE NEAR THE TRINITY HORN MONDAY AND TUESDAY  
AFTERNOONS, BUT MOST OF THIS ACTIVITY WILL BE FOCUSED FARTHER TO  
THE NORTH AND EAST. DRY CONDITIONS WILL PREVAIL THROUGH THE  
REMAINDER OF THE WEEK.  
 

 
   
AVIATION
 
VERY WIDESPREAD MARINE STRATUS THIS MORNING THAT  
STRETCHED FROM WA/OR BORDER ALL THE WAY DOWN TO THE BAY AREA AND  
POINT SOUTH. FOR US IN THE REDWOOD COAST, THE STRATUS HANGS AROUND  
IN KCEC AND KACV THROUGHOUT THE DAY. BOTH LOCATIONS WERE REPORTING  
LIFR THIS MORNING. CONDITIONS GRADUALLY IMPROVED TO MVFR/IFR.  
HOWEVER, DO NOT EXPECT THE IMPROVED CONDITIONS TO LAST LONG. WITH  
CONTINUING SW-LY ONSHORE FLOW, THAT IS GOING TO BRING IN A DEEPER  
MARINE LAYER INTO THE AREA. DO EXPECT CONDITIONS TO WORSEN TO  
IFR/LIFR THIS EVENING, AND THEN GRADUALLY IMPROVE TOMORROW MORNING.  
KUKI SHOULD STAY VFR OVERNIGHT, BUT THERE IS A POTENTIAL WHERE SOME  
STRATUS CAN SNEAK IN OVERNIGHT AND POTENTIALLY LOWER THE CONDITIONS  
DOWN TO MVFR. IT WILL BE BACK UP TO VFR DURING THE DAY FOR KUKI.  
 

 
   
MARINE
 
LIGHT WINDS AND LOW SEAS INTO MONDAY. A TROUGH OF LOW  
PRESSURE REMAINS OFF THE COAST OF CALIFORNIA THROUGH TOMORROW. THIS  
ALLOWS THE PRESSURE GRADIENT TO REMAIN RELAXED. DO EXPECT LIGHT  
WINDS AND RESULTANT LOW SEAS THROUGH MONDAY.  
 
WE WILL RETURN TO A STRONG NORTHERLY WIND REGIME STARTING ON TUESDAY  
AS THE EAST PACIFIC HIGH RE-ESTABLISHES ITSELF. WITH TIGHT NORTHERLY  
PRESSURE GRADIENT, THE STRONG NORTHERLY WIND REGIME WILL PERSIST  
THROUGH MOST OF THE WEEK. GALE FORCE WIND GUSTS WILL BE LIKELY  
STARTING MIDDLE OF THE WORK WEEK.  
 
FORECAST IS STILL ON TRACK. LITTLE CHANGES WERE MADE TO THE PREVIOUS  
FORECAST PACKAGE. GFS IS USED TO UPDATE THE FORECAST PACKAGE.  
 

 
   
FIRE WEATHER
 
ISOLATED TO SCATTERED THUNDERSTORMS HAVE DEVELOPED  
ACROSS SISKIYOU COUNTY THIS AFTERNOON, AND A FEW ARE BEGINNING TO  
DEVELOP ACROSS CENTRAL TRINITY COUNTY AS OF 3 PM AS WELL. THIS  
ACTIVITY IS EXPECTED TO CONTINUE TO MATURE THROUGH THE REMAINDER  
OF THE AFTERNOON, WITH ISOLATED LIGHTNING STRIKES AND ERRATIC  
GUSTY WINDS EXPECTED. DRY SUB-CLOUD LAYERS WILL ALSO LIMIT THE  
AMOUNT OF RAIN THAT REACHES THE LOWER ELEVATIONS AS WELL. HOWEVER,  
FUELS REMAIN MARGINAL FOR LARGE FIRE GROWTH IN THE NORTHWESTERN  
MOUNTAINS AT THIS TIME...ALTHOUGH FUELS HAVE DRIED CONSIDERABLY  
OVER THE PAST WEEK. ISOLATED STORMS WILL BE POSSIBLE AGAIN  
TOMORROW AFTERNOON AND TUESDAY AFTERNOON NEAR THE TRINITY HORN.  
/BRC  
 

 
   
EKA WATCHES/WARNINGS/ADVISORIES
 
 
CA...NONE.  
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.  

 
 

 
 
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