138
FXUS66 KEKA 232320
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
420 PM PDT WED SEP 23 2026
KEY MESSAGES
* A PASSING COLD FRONT BRINGS A HIGH CHANCE OF LIGHT RAIN TO DEL
NORTE AND NORTHERN HUMBOLDT LATE THURSDAY NIGHT INTO FRIDAY.
* GUSTY WINDS LATE THURSDAY AND INTO FRIDAY.
* DRY CONDITIONS AND GUSTY WINDS WILL BRING ELEVATED FIRE WEATHER
CONDITIONS TO SOUTHERN MENDOCINO, LAKE COUNTIES AND AREAS OF
TRINITY COUNTY THURSDAY AFTERNOON.
* COOLER TEMPERATURES WILL ARRIVE THIS WEEKEND BEHIND THE FRONT,
BRINGING CHANCES FOR ISOLATED INTERIOR FROST.
SYNOPSIS
AN APPROACHING COLD FRONT INTRODUCES MORE EXTENSIVE
CLOUD COVER AND A CHANCE FOR MEASURABLE RAIN TO DEL NORTE AND
NORTHERN HUMBOLDT COUNTIES LATE THURSDAY NIGHT INTO FRIDAY. COLDER
TEMPERATURES WILL FOLLOW THROUGH THE WEEKEND. GUSTY WINDS ASSOCIATED
WITH THE FRONT WILL BRING ELEVATED FIRE WEATHER CONDITIONS TO LAKE
COUNTY THURSDAY AFTERNOON.
DISCUSSION
A TROUGH WITH A COMPACT AND DEEPENING SURFACE LOW WILL
NEAR THE REGION, CLIPPING NW CA LATE THURSDAY. THOUGH THERE WILL BE
SOME STRONG DYNAMICS WITH THE STORM SYSTEM, THE TRACK AS TRENDED
FARTHER NORTH ON RECENT MODEL GUIDANCE. THIS WILL LIMIT THE IMPACTS
AND TOTAL MEASURABLE RAINFALL. THE BEST SHOT OF LIGHT RAIN WILL BE
FROM DEL NORTE TO NORTHERN HUMBOLDT. CHANCES FOR ANYTHING OVER 0.1
INCHES QUICKLY LOWER TO ZERO SOUTH OR EAST OF CAPE MENDOCINO.
THE INTERIOR RIDGES WILL SEE SOME GUSTY WINDS FROM THE STRONGER
WINDS ALOFT WITH THE TROUGH. THERE IS A HIGH CHANCE (70%) FOR GUSTS
TO EXCEED 30 MPH COASTAL AND INTERIOR RIDGES OF DEL NORTE LATE
THURSDAY INTO FRIDAY MORNING. CHANCES FOR GUSTS OVER 25 MPH AND
LOCALLY UP TO 30 MPH ARE ALSO HIGH FOR SOUTH MENDOCINO AND LAKE
COUNTIES THURSDAY AFTERNOON. THIS WILL CREATE SOME FIRE WEATHER
CONCERNS FOR THOSE AREAS DUE TO THE DRIER CONDITIONS.
A COLDER AIR MASS WILL ARRIVE OVERNIGHT FRIDAY. THIS WILL BRING THE
POTENTIAL FOR FROST FOR SOME OF THE INTERIOR VALLEYS. CHANCES FOR
CHILLY TEMPERATURES AND FROST WILL CONTINUE INTO AT LEAST EARLY NEXT
WEEK. A TROUGH WILL PASS THROUGH SUNDAY. THIS STORM SYSTEM AND A
SHORTWAVE DISTURBANCE PRECEDING IT SATURDAY WILL BE MOSTLY DRY, BUT
COULD BRING AN AFTERNOON SHOWER OR TWO FOR THE INTERIOR. THE
EXTENDED OUTLOOK LOOKS TO REMAIN DRY WITH NO CHANCE FOR WETTING
RAINFALL.
AVIATION...00Z TAFS
THE WEAKENED INVERSION AND CONTINUED
NORTHERLY WINDS ALLOWED FOR STRATUS TO QUICKLY MIX OUT WEDNESDAY.
THOUGH A TROUGH WILL APPROACH THE AREA TUESDAY, SUBSIDENCE AHEAD
OF IT HAS QUICKLY COMPRESSED THE INVERSION, WITH AFTERNOON
OBSERVATIONS SHOWING THE CEILINGS DOWN TO 200 FT. THIS INCREASES
CONFIDENCE FOR LIFY CONDITOIONS FOG THROUGH THURSDAY MORNING FOR
THE COASTAL TERMINALS. LIGHT WINDS WILL PERSIST INTO FRIDAY MORNING.
VFR CONDITIONS WILL PERSIST ELSEWHERE APART FOR SOME POTENTIAL
STRATUS PUSHING INTO THE FORT BRAGG AREA.
MARINE
A TROUGH APPROACHING FROM THE WEST WILL BEGIN TO SLOWLY
WEAKEN THE NORTHERLIES TONIGHT AS SMALL MID PERIOD NW SWELLS REMAIN.
A STRONG AREA OF LOW PRESSURE WILL PASS BY WELL OFFSHORE
THURSDAY. THOUGH THE W TO SW WINDS WILL REMAIN RELATIVELY LIGHT,
THERE WILL A STRONG WESTERLY WIND FETCH AROUND THE LOW WHICH WILL
DRIVE IN A QUICK PULSE OF STEEP WEST NORTHWESTERLY SEAS AROUND
9-11 FT AT 10-11 SECONDS FOR MOST OF THE WATERS. SEAS MAY REACH
HAZARDOUS LEVELS AT 12 FT FOR THE FAR NW WATERS OUT AROUND 30 TO
60 NM. THESE SEAS WILL INCREASE RAPIDLY LATE THURSDAY THROUGH
FRIDAY MORNING AND WILL BRING DANGEROUS CONDITIONS TO SMALL
CRAFTS. THE NORTHERLIES WILL RESTRENGTHEN FRIDAY AFTERNOON, AND
WILL BE NEAR GALE TO GALE STRENGTH IN AT LEAST THE OUTER WATERS BY
SATURDAY.
FIRE WEATHER
A TROUGH AND SURFACE LOW WILL CLIP THE REGION
THURSDAY. LIGHT PRECIPITATION IS EXPECTED FROM AROUND CAPE MENDOCINO
AND NORTHWARD THROUGH NORTHERN HUMBOLDT AND DEL NORTE, WITH NO
PRECIPITATION EXPECTED SOUTH AND EAST OF THE CAPE. THIS STORM SYSTEM
WILL INCREASE WESTERLY WINDS THURSDAY AFTERNOON AND INTO FRIDAY. RH
WILL BE ON THE RISE WITH THE MOIST FLOW, BUT THERE WILL BE A PERIOD
OF NEAR TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS THURSDAY
AFTERNOON IN SOUTHERN TRINITY, SOUTHERN MENDOCINO, AND LAKE COUNTY
(ZONES 411, 416, 419, 420, AND 421). RECOVERIES WILL BE GOOD
OVERNIGHT THURSDAY. NORTHERLY TO WESTERLY WINDS WILL TURN GUSTY
FRIDAY WHILE RH REMAINS HIGHER. A PRONOUNCED OFFSHORE WIND SURGE
WILL THEN DEVELOP FRIDAY NIGHT, DRYING OUT THE INTERIOR SOMEWHAT
SATURDAY WITH MIN RH DROPPING TO THE LOW 20 TO UPPER TEENS. THE
EXTENDED FORECAST DOES NOT INCLUDE ANY MORE CHANCES FOR WETTING
RAIN.
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY FROM 2 AM TO 5 PM PDT FRIDAY FOR
PZZ450.
SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR PZZ455.
SMALL CRAFT ADVISORY FROM 11 PM THURSDAY TO 5 PM PDT FRIDAY
FOR PZZ470.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT THURSDAY FOR PZZ475.
SMALL CRAFT ADVISORY FROM 5 AM TO 5 PM PDT FRIDAY 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
FOLLOW US ON FACEBOOK AND TWITTER AT:
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page