695
FXUS66 KEKA 300803
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
103 AM PDT SAT AUG 30 2025
SYNOPSIS
NEAR SEASONAL AVERAGE TEMPERATURES WILL CONTINUE
THROUGH THE WEEKEND. INCREASING HEAT IS EXPECTED ACROSS THE
INTERIOR EARLY THROUGH MID NEXT WEEK. THE COAST IS EXPECTED TO SEE
NIGHT AND MORNING CLOUDS WITH SOME AFTERNOON CLEARING MOST DAYS.
THERE IS A SLIGHT CHANCE OF THUNDERSTORMS TUESDAY AND WEDNESDAY IN
THE INTERIOR.
DISCUSSION
AN UPPER LEVEL LOW OFF THE PACIFIC NORTHWEST IS
NEARLY STATIONARY AND THIS IS EXPECTED TO CONDITIONS FAIRLY
SIMILAR OVER THE NEXT COUPLE DAYS. THE COOLER TEMPERATURES ALOFT
ARE GENERALLY KEEPING THE MARINE INVERSION WEAKER AND THIS IS
ALLOWING SKIES TO CLEAR OUT AT THE COAST IN THE AFTERNOONS.
INTERIOR HIGH TEMPERATURES ARE GENERALLY EXPECTED TO BE IN THE
MID 80'S TO MID 90'S, WHILE MID 60'S TO LOW 70'S ALONG THE COAST.
SMOKE FROM THE ACTIVE WILDFIRES IN SISKIYOU AND TRINITY COUNTIES
WILL CONTINUE TO BE PUSHED TOWARD NORTHEAST THROUGH THE WEEKEND
WITH THE SOUTH TO SOUTHWESTERLY BREEZES ALOFT. THIS WILL GENERALLY
PUSH THE SMOKE OUT OF THE AREA. THE EXCEPTION WILL BE AREAS NORTH
OF THE PEAK FIRE BETWEEN TRINITY LAKE AND GRANITE PEAK. THERE
WILL LIKELY BE LOCAL TERRAIN EFFECTS THAT MAY BRING SMOKE TO THE
VALLEYS IN ALL DIRECTIONS NEAR THE FIRES. THIS WILL BE ESPECIALLY
TRUE IF THE FIRE IS BURNING BELOW THE INVERSION AND THE SMOKE IS
TRAPPED. FOR DETAILS VISIT WEATHER.GOV/EKA AND CHECK OUT THE AREA
SMOKE FORECAST ON THE BOTTOM OF THE MAIN PAGE.
MONDAY THE UPPER LEVEL LOW STARTS TO PUSH NORTHWEST TOWARDS THE
GULF OF ALASKA AND HIGH PRESSURE BUILDS NORTH INTO THE AREA.
INLAND TEMPERATURES ARE EXPECTED TO WARM ABOVE NORMAL WITH HIGHS
NEAR 100 IN MANY OF THE INLAND VALLEYS. ADDITIONAL WARMING IS
EXPECTED TUESDAY WITH HIGHS AROUND 100 TO 105 IN MANY OF THE
INLAND VALLEYS. TUESDAY IS LIKELY TO BE THE HOTTEST DAY, ALTHOUGH
ANY COOLING ON WEDNESDAY THURSDAY IS EXPECTED TO BE MINOR.
TUESDAY OR WEDNESDAY A SHORTWAVE MOVING UP THE WEST SIDE OF THE
RIDGE IS EXPECTED TO DRAW SOME MOISTURE UP AND THIS WILL BRING THE
POTENTIAL FOR THUNDERSTORMS OVER THE INTERIOR. THE ENSEMBLE
CLUSTERS ARE IN PRETTY GOOD AGREEMENT ON THIS PATTERN WITH AROUND
70 PERCENT OF THE MEMBERS SHOWING THIS SHORTWAVE. THE CHALLENGE IS
IN THE DETAILS OF THE TIMING AND HOW MUCH MOISTURE IS AVAILABLE.
THE GFS HAS A FASTER SOLUTION WITH THE THREAT FOR THUNDERSTORMS
OVER BY WEDNESDAY MORNING WHILE THE ECMWF IS SLOWER AND HAS
CHANCES FOR THUNDERSTORMS INTO WEDNESDAY. IT LOOKS LIKE THERE IS
ENOUGH ENERGY ALOFT THERE COULD BE SOME NOCTURNAL STORMS. FOR NOW
HAVE ADDED THUNDERSTORMS TO NORTHERN TRINITY COUNTY TUESDAY AND
WEDNESDAY AFTERNOONS. COVERAGE MAY BE MORE WIDESPREAD THAN THIS OR
CONTINUE OVERNIGHT, BUT WILL WAIT FOR MORE MODEL RUNS TO INCREASE
CONFIDENCE. MKK
AVIATION...(06Z TAFS)
A LOW PRESSURE SYSTEM OFF THE COAST OF
OREGON IS SLINGING A FEW BANDS OF MOISTURE TOWARDS OUR COASTAL
TERMINALS. MOST OF THE REFLECTIVITY SHOWING CONVECTIVE ACTIVITY IS
HEADED NORTH OF KCEC AS OF 04Z. A DEEPENING MARINE LAYER WILL KEEP
THE CLOUD DECK AT 2000 FEET OR BETTER IF CLOUDS CONGLOMERATE. WITH
THAT SAID IF SKIES REMAIN CLEAR, THE LACK OF CLOUD COVER MAY ALLOW IN
COOLING AT LOW LEVELS AND FOG COULD FORM NEAR GROUND LEVEL. THIS
WILL BE PATCHY AT ITS WORST. THE PROBABILITY OF CEILINGS LESS THAN
500FT FOR KCEC AND KACV IS AROUND 55-60% FOR THE EARLY MORNING
TIMEFRAME BEFORE SUNRISE. KUKI WILL HAVE PREVAILING VFR CONDITIONS
BUT IT LOOKS LIKE NORTHWESTERLY WINDS COULD PICK UP WITH THE LATE
AFTERNOON DIURNAL SWING AT 15+ KNOT GUSTS. /EYS
MARINE
NORTHERLY WINDS ARE EXPECTED TO CONTINUE TO INCREASE IN
THE SOUTHERN WATERS SATURDAY AFTERNOON WITH AN AREA OF 15 TO 20 KT
WINDS, ESPECIALLY DOWNWIND OF CAPE MENDOCINO. MODELS ARE IN GOOD
AGREEMENT THAT THE WIND IN THE NORTHERN WATERS WILL REMAIN LIGHT. ON
SUNDAY HOWEVER, THE WINDS MAY INCREASE SLIGHTLY MORE, ESPECIALLY IN
THE SOUTHERN WATERS. MOST MODELS SUGGEST THEY MAY REACH CLOSE TO
20 KT. NORTHERLY WINDS ARE EXPECTED TO PERSIST, AND POTENTIALLY
EVEN INCREASE NEXT WEEK AS WELL. MARGINAL SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED SUNDAY IN THE OUTER WATERS (PZZ475) AND
NEAR SHORE WATERS, SOUTH OF CAPE MENDOCINO (PZZ455) WHERE
THERE MAY BE A FEW GALE FORCE GUSTS SOUTH OF CAPE MENDOCINO.
WAVES REMAIN CALM, AROUND 2 TO 3 FEET. THIS IS MOSTLY FROM A
SOUTHERLY AT ~17 SECONDS. THESE WAVES ARE GENERALLY EXPECTED TO
CONTINUE THROUGH THE WEEKEND WITH THE ADDITION OF SHORT PERIOD WIND
WAVES AS THE WINDS START TO PICK UP. THERE IS A SMALL THREAT FOR
SOME SNEAKER WAVES ALONG SW FACING BEACHES, BUT WITH THE SOUTHERLY
SWELL EXPECTED TO BE COMPARATIVELY SMALL AND NOT TOO LONG OF A
PERIOD, THE THREAT IS NOT EXPECTED TO BE VERY SIGNIFICANT.
FIRE WEATHER
ELEVATED FIRE WEATHER CONDITIONS DUE TO LOW RH
AND BREEZY SOUTHWESTERLY WINDS OVER THE HIGHER TERRAIN IN ZONES
277, 283 & 264 CONTINUE THIS WEEKEND. SURFACE OBSERVATIONS
REPORTED DAYTIME RH VALUES IN THE SINGLE DIGITS TO MID TEENS
ACROSS TRINITY, LAKE AND INTERIOR MENDOCINO COUNTIES FRIDAY
AFTERNOON. WINDS WILL CONTINUE TO BE LIGHT AND TERRAIN DRIVEN WITH
GENERAL INCREASE IN WESTERLY WINDS IN THE AFTERNOON. MORE WIND
PRONE AREAS COULD SEES GUSTS UP TO AROUND 25 MPH IN THE AFTERNOON.
THE ONSHORE MARINE MOISTURE WILL BRING A SLIGHT IMPROVEMENT IN
THE OVERNIGHT RH RECOVERIES ACROSS THE INTERIOR, BUT THESE ARE
EXPECTED TO REMAIN POOR OVER THE HIGHER TERRAIN WITH VALUES IN THE
30'S IN TRINITY, LAKE AND EASTERN MENDOCINO COUNTIES.
WARMING AND DRYING TREND IS EXPECTED EARLY THROUGH MID NEXT WEEK
AS THE HIGH PRESSURE BUILD IN, WITH HIGH TEMPERATURES ACROSS THE
INTERIOR VALLEYS PEAKING IN THE 90S AND INTO 100S ON TUESDAY AND
WEDNESDAY. THE AFTERNOON RH VALUES WILL LIKELY BE IN THE TEENS AND
EVEN IN THE SINGLE DIGITS ACROSS TRINITY, LAKE AND EASTERN
MENDOCINO COUNTIES. HUMIDITY RECOVERIES WILL GRADUALLY DIMINISH
THROUGH THE WEEKEND AND EARLY NEXT WEEK, WITH LOCALLY VERY POOR
RECOVERIES BY TUESDAY.
A SHORTWAVE MOVING UP THE WEST SIDE OF THE RIDGE WILL BRING A
THREAT OF THUNDERSTORMS FOR TUESDAY AND WEDNESDAY. THERE ARE STILL
DIFFERENCES ON TIMING AND LOCATION, BUT A GROWING NUMBER OF THE
ENSEMBLE CLUSTERS ARE SHOWING THIS SHORTWAVE. SO HAVE ADDED
THUNDERSTORMS TO NORTHERN TRINITY COUNTY TUESDAY EVENING AND
WEDNESDAY AFTERNOON AND EVENING. THIS COVERAGE MAY NEED TO BE
INCREASED AS IT BECOMES MORE CLEAR ON THE LOCATION OF STORMS.
THESE STORMS MAY CONTINUE OVERNIGHT IF THE SHORTWAVE, MOISTURE
AND INSTABILITY LINE UP RIGHT. IT ALSO LOOKS LIKE ANY STORMS THAT
FORM WILL BE FAIRLY DRY. MKK/ZVS
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY FROM 11 AM TO 11 PM PDT SUNDAY FOR
PZZ455.
SMALL CRAFT ADVISORY FROM 5 AM TO 11 PM PDT SUNDAY 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.
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