234
FXUS66 KEKA 212252
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
252 PM PST WED JAN 21 2026
SYNOPSIS
DRY WEATHER AND ABOVE NORMAL DAYTIME TEMPERATURES
WILL CONTINUE THROUGH THE EARLY NEXT WEEK. OVERNIGHT AND MORNING
TEMPERATURES WILL REMAIN CHILLY WITH PATCHY DENSE FOG ALONG THE
RIVER VALLEYS AND AROUND HUMBOLDT BAY. CHANCE OF PRECIPITATION
INCREASE BY MID NEXT WEEK.
DISCUSSION
PARTLY TO MOSTLY CLOUDY SKIES ARE OBSERVED ACROSS NW
CALIFORNIA THIS AFTERNOON, WITH MID- TO HIGH-LEVEL CLOUDS
STREAMING NORTHWARD. THIS MOISTURE IS ASSOCIATED WITH A CUT-OFF
LOW APPROXIMATELY 330 MILES OFF THE CENTRAL CALIFORNIA, WHICH
CONTINUES TO TRACK SOUTHWARD. HIGH PRESSURE WILL REBUILD IN THE
WAKE OF THIS LOW TONIGHT THROUGH FRIDAY, LEADING TO DRIER OFFSHORE
FLOW. THIS WILL PROMOTE IMPROVED SKY CONDITIONS ON THURSDAY, WITH
CLEAR SKIES ACROSS MUCH NW CALIFORNIA FRIDAY AND INTO THE
WEEKEND.
A DRY OFFSHORE FLOW WILL MOST LIKELY REINFORCE CHILLY OVERNIGHT
LOWS, BRINGING A CHANCE OF NEAR-FREEZING OR FREEZING TEMPERATURES
TO COASTAL AREAS AND ADJACENT VALLEYS FRIDAY NIGHT INTO SATURDAY
MORNING. GRANTED PLACES WHERE WINDS STAY UP ALL NIGHT, TEMPERATURES
PROBABLY WILL NOT EVEN FALL BELOW 50F. LOWER DEWPOINTS, CLEAR
SKIES AND LIGHT WINDS AT NIGHT WILL ALLOW FOR IDEAL LONG WAVE
COOLING AGAIN. FREEZING OR NEAR-FREEZING TEMPERATURES ARE
PROBABLE FRIDAY AND SATURDAY MORNING, BOTH ALONG THE COAST AND IN
THE WIND- SHELTERED COASTAL VALLEYS. SUB-FREEZING TEMPERATURES
ARE A SURE THING IN INTERIOR VALLEYS, ESPECIALLY TRINITY AND
NORTHERN MENDOCINO.
DRY WEATHER IS EXPECTED TO PERSIST THROUGH THE WEEKEND AND INTO
EARLY NEXT WEEK AS THE HIGH PRESSURE PERSIST OVER THE EASTERN
PACIFIC, THOUGH THE RIDGE WEAKEN. A WEAK SHORTWAVE TROUGH WILL
BRING INCREASING CLOUDINESS SATURDAY NIGHT AND SUNDAY. COASTAL
STRATUS ARE ANTICIPATED TO REDEVELOP, WITH A SLIGHTLY DEEPER
MARINE LAYER ALONG THE NORTH COAST. ASIDE OF SOME PATCHY COASTAL
DRIZZLE, GENERALLY DRY CONDITIONS AND ABOVE NORMAL DAYTIME
TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH THE EARLY NEXT WEEK.
LONG-RANGE MODELS CONTINUE TO SUGGEST AN INCREASING CHANCE OF
PRECIPITATION FROM MID- TO LATE NEXT WEEK. UNCERTAINTIES REMAIN
HIGH IN THE DETAILS. STAY TUNED FOR UPDATES AS THE TIMING OF THIS
SHIFT BECOME CLEARER. /ZVS
AVIATION...(18Z TAFS)
UPPER LOW OVER THE OFFSHORE WATERS OF
CENTRAL CALIFORNIA WILL CONTINUE TO SPREAD OCCASIONAL MID AND HIGH
LEVEL CLOUDS OVER THE AREAS TONIGHT. OFFSHORE LOW HAS INDUCED A
SLIGHT N-NE FLOW OVER COASTAL AREAS AND STRATUS AND FOG HAS BEEN
MUCH LESS PERSISTENT FOR THE HUMBOLDT BAY AREA AND OVER KACV VS THE
LAST 2 DAYS. HIGH RESOLUTION MESOSCALE ENSEMBLE (HREF) INDICATE LOWER
CHANCES FOR LIFR TONIGHT FOR COASTAL FORECAST TERMINALS. HIGH
BOUNDARY LAYER HUMIDITY MAY STILL RESULT IN MOSTLY MVFR VSBY
OBSCURATION IN MIST ONCE THE SUN GOES DOWN AND PERHAPS FLEETING
CEILINGS AROUND 500-1500 FEET. OTHERWISE, EXPECTING MOSTLY VFR
CONDITIONS EXCEPT FOR PATCHES OF FOG AND LOW CLOUDS IN THE INTERIOR
RIVER VALLEYS LATE TONIGHT AND EARLY THU MORNING. NORTHERLIES
INCREASE OFFSHORE LATE ON THU, HOWEVER SHALLOW LOW LEVEL TURBULENCE
AND/OR LOW LEVEL WIND SHEAR WILL MOST LIKELY NOT BECOME A HAZARD FOR
SMALL AIRCRAFT UNTIL THU NIGHT AFTER 23/00Z.
MARINE
NORTHERLY WINDS WILL INCREASE SLIGHTLY TONIGHT AS A WEAK
LOW APPROACHES THE CENTRAL AND SOUTHERN CALIFORNIA COAST WHILE HIGH
PRESSURE NOSES TOWARD THE PAC NW COAST. SURFACE WIND FIELDS DO NOT
APPEAR STRONG ENOUGH TO WARRANT AN ADVISORY FOR SMALL CRAFT TONIGHT
WITH GUSTS UP TO 18-22 KT AND SHORT PERIOD WAVES 5 FT OR LESS FOR
THE OUTER WATERS. NORTHERLY PRESSURE GRADIENTS TIGHTEN ON THU AS A
MID LEVEL SHORTWAVE TROUGH IN NW FLOW ALOFT MOVES ACROSS THE PAC NW.
HIGH RESOLUTION ENSEMBLE GUIDANCE INDICATES HIGH CHANCES FOR GUSTS
TO 25-30 KT (80% CHANCE OR MORE) WITH GALE GUSTS OVER 34 KT MUCH
MORE PROBABLE (>60% CHANCE) FOR THE NORTHERN PORTION OF PZZ470 BY 4
TO 8 PM THURSDAY. GALE GUST COVERAGE INCREASES AFTER 8-10PM WITH
VERY STEEP SEAS BUILDING TO 9-11 FT OVERNIGHT INTO FRIDAY. THUS THE
WATCH FOR GALES HAS BEEN UPGRADED TO WARNING AS COMBINED SEAS BUILD
TO 12 TO 15 FEET IN THE OUTER WATERS BY FRI AFTERNOON. OCEAN
CONDITIONS WILL ALSO DETERIORATE THU NIGHT AND FRIDAY FOR THE INNER
WATERS. GALE GUSTS ARE CERTAINLY PROBABLE AROUND NOTORIOUS WIND
PRONE LOCATIONS SUCH AS CAPE MENDOCINO AND PERHAPS AROUND PT ST
GEORGE. PRIMARY HAZARD FOR THE WATERS APPEARS TO BE LARGE STEEP
WAVES ARISING FROM THE STRONG NORTHERLIES OFFSHORE. CONFIDENCE SEAS
WILL BE SUFFICIENTLY ELEVATED AND VERY STEEP FOR A WARNING ACROSS
THE INNER WATERS IS NOT HIGH. PERHAPS BUOYS ON THE OUTER FRINGES OF
THE INNER WATERS WILL BE REPORT WARNING CRITERIA. FOR NOW, A SMALL
CRAFT ADVISORY WILL BE SUFFICIENT TO LET MARINERS IN SMALL CRAFT
KNOW ABOUT DETERIORATING MARINE CONDITIONS AND PLAN ACCORDINGLY.
NOW CONDITIONS LOOK TO GRADUALLY IMPROVE OVER THE WEEKEND AS THE
AXIS OF STRONG NORTH WIND SHIFTS OUTSIDE OF NW CALIFORNIA WATERS AND
STEEP WIND WAVES GRADUALLY SUBSIDE. IN THIS MIX OF STEEP SHORT
PERIOD WAVES WILL BE A LONG PERIOD (>16 SECONDS) WESTERLY SWELL ON
THU THAT WILL DECAY THROUGH FRI. A MID PERIOD SWELL NEAR 14 SECOND
FOLLOW ON FRI, FOLLOWED BY THIRD MID PERIOD GROUP ON SAT. NONE OF
THESE APPEAR TO POSE A RISK FOR SNEAKER WAVES AT THIS TIME.
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY FROM 7 PM THURSDAY TO 3 AM PST
SATURDAY FOR PZZ450.
SMALL CRAFT ADVISORY FROM 10 PM THURSDAY TO 3 AM PST
SATURDAY FOR PZZ455.
SMALL CRAFT ADVISORY FROM 10 AM TO 10 PM PST THURSDAY FOR
PZZ470-475.
GALE WARNING FROM 10 PM THURSDAY TO 3 AM PST SATURDAY FOR
PZZ470-475.
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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