436
FXUS66 KEKA 122057
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
157 PM PDT TUE MAY 12 2026
SYNOPSIS
AN UPPER LEVEL LOW WILL COOL TEMPERATURES SLIGHTLY TODAY
WITH SOME LIGHT RAIN TONIGHT AND EARLY WEDNESDAY FOR THE NORTH
COAST. COOL TEMPERATURES WEDNESDAY WITH WARMING AGAIN THURSDAY
BEFORE A WEAK SHORTWAVE UPPER LEVEL DISTURBANCE BRINGS COOLER
TEMPERATURES FRIDAY AND SATURDAY. WARMER WEATHER EXPECTED EARLY
NEXT WEEK.
KEY MESSAGES
- LIGHT RAIN OR DRIZZLE FORECAST FOR TONIGHT AND WEDNESDAY MORNING
FOR DEL NORTE AND HUMBOLDT COUNTIES, MOSTLY DRY WEATHER FOR AREAS
FARTHER EAST AND SOUTH.
- BREEZY WINDS FOR LAKE COUNTY TONIGHT.
- BREEZES GROW MORE WIDESPREAD THURSDAY INTO THIS WEEKEND.
DISCUSSION
THE APPROACHING UPPER-LEVEL TROUGH IS DEEPENING THE
MARINE LAYER, COOLING TEMPERATURES ACROSS THE FORECAST AREA. THE
GREATEST EFFECT OF THIS DEEPENING IS NEAR THE COAST WHERE TODAY
IS AROUND 10DEGF COOLER THAN YESTERDAY. FURTHER INLAND, TRINITY
COUNTY, EASTERN MENDOCINO COUNTY AND LAKE COUNTY IS SHOWING ONLY A
FEW DEGREES OF COOLING AT MOST. TONIGHT INTO WEDNESDAY MORNING,
THE WEAK FRONTAL BOUNDARY WILL FORCE VERY LIGHT RAIN FOR HUMBOLDT
AND DEL NORTE COUNTIES. TOTALS OF 0.10-0.25" IS EXPECTED IN THESE
COUNTIES, WITH THE HEAVIEST RAIN, UP TO 0.35",FORECASTED FOR THE
MOUNTAINS OF DEL NORTE COUNTY. FARTHER SOUTH AND EAST, ONLY A
TRACE OF RAIN IS FORECASTED <0.01" FOR VALLEYS. HIGH TEMPERATURES
WILL BE NOTABLY LOWER ON WEDNESDAY DUE TO COLD AIR ADVECTION. THIS
FRONT WILL ALSO FORCE STRONG WINDS TONIGHT INTO WEDNESDAY,
PARTICULARLY FOR LAKE COUNTY AS THE WIND DIRECTION ALIGNS WITH
CLEAR LAKE. GUSTS OF 25MPH ARE POSSIBLE WITH A 10% CHANCE OF GUSTS
>35MPH.
WEDNESDAY AFTERNOON THROUGH THURSDAY, HIGH PRESSURE STARTS TO
BUILD INTO THE AREA PROMOTING CLEAR SKIES AS MOST OF THE INLAND
AREAS CAN EXPECTED DAYTIME HIGHS WARMING INTO THE 80S. FRIDAY AND
SATURDAY THE UPPER LEVEL FLOW EVOLVES TOWARDS A MORE ZONAL SETUP
AS A SHORTWAVE MOVES OVER WASHINGTON STATE. THIS CHANGE FORCES
SLIGHTLY COOLER TEMPERATURES FRIDAY WITH ADDITIONAL COOLING ON
SATURDAY. ALSO, MORE WIDE SPREAD GUSTY WINDS ARE EXPECTED
STARTING ON THURSDAY AND INCREASING FRIDAY AND INTO THE WEEKEND.
GUSTS OF 20 TO 30 MPH ARE POSSIBLE WITH LOCALLY HIGHER GUSTS UP TO
40MPH POSSIBLE IN LOCALIZED AREAS.
ENSEMBLE PREDICT A RETURN OF HIGH PRESSURE ON SUNDAY AND RETURN
OF THE INLAND HEAT. THIS WILL BRING SOME OFFSHORE FLOW FOR MONDAY
MORNING LEADING TO A POTENTIAL CLEARING OF COASTAL CLOUDS. THESE
OFFSHORE WINDS WILL BE SHORT-LIVED. THIS HIGH PRESSURE LOOKS TO BE
A CATALYST FOR A THERMAL TROUGH PATTERN LEADING TO BREEZY WINDS
ALONG THE COAST, LIKELY HELP KEEP THE HIGH TEMPERATURES ON THE
COAST NORMAL. INLAND, AREAS ARE PREDICTED TO WARM INTO THE UPPER
80S TO LOW 90S. MINOR HEAT RISK IS POSSIBLE FOR MUCH OF THE
INTERIOR NEXT WEEK IF THIS FORECAST REMAINS ON TRACK. MKK/DS
AVIATION
AN APPROACHING COLD FRONT IS FORCING VARIABLE CONDITIONS
AT NORTH COAST TERMINALS TODAY. OVERCAST CEILINGS ARE FORECASTED TO
SCATTER SLIGHTLY THROUGH MIDDAY BEFORE SOUTHERLY WINDS AND OVERCAST
CONDITIONS RETURN THIS EVENING. THIS FRONTAL WILL BE RELATIVELY WEAK
AND DATA SHOWS ONLY A 50% LIKELIHOOD OF MVFR CEILINGS DEVELOPING
OVER THE NORTH COAST TERMINALS FROM 08Z-15Z (+/-1HR). CONDITIONS
WEDNESDAY LOOK TO BE VFR FROM 18Z THROUGH THE DAYLIGHT HOURS. INLAND
TERMINALS WILL EXPERIENCE GUSTIER WINDS DUE TO THIS FRONTAL PASSAGE.
WINDS ALOFT ~2500FT AGL WILL BE AROUND 35KTS OUT OF THE NW AND HAVE
THE POTENTIAL TO MIX DOWN TO TERMINALS, ESPECIALLY THOSE IN OPEN OR
N-S ORIENTATED VALLEYS. VFR FOR INLAND AREAS THROUGH THE TAF
PERIOD. DS
MARINE
LIGHT TO MODERATELY BREEZY NW WINDS WILL REMAIN FOR THE
SOUTHERN WATERS. FOR THE WATERS NORTH OF CAPE MENDOCINO, A SOUTHERLY
WIND SHIFT WILL OCCUR THIS AFTERNOON/EVENING AS A WEAK COLD FRONT
ENTERS THE AREA. AFTER THIS FRONTAL PASSAGE, A THERMAL TROUGH IS
PREDICTED TO DEVELOP, WHICH, INTERACTING WITH AN INCOMING PACIFIC
HIGH PRESSURE WILL FORCE NW WINDS BY DAWN WEDNESDAY. WEDNESDAY
THROUGH FRIDAY SHOWS THESE WINDS INCREASING WITH OVER A 70% CHANCE
OF GUSTS OVER 35KTS SOUTH OF CAPE MENDOCINO AND NEAR GALE GUSTS
ELSEWHERE. DUE TO THESE WINDS, A GALE WATCH HAS BEEN ISSUED FOR
PZZ475 BEGINNING WEDNESDAY AFTERNOON.
THE SEA STATE WILL CONTINUE TO BE DOMINATED BY A MID- PERIOD
WESTERLY SWELL AND SHORT PERIOD NORTHERLY WINDS, ESPECIALLY LATE
WEEK. SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED POSSIBLE
WEDNESDAY AFTERNOON THROUGH THE END OF THE WEEK AS STEEP SHORT
PERIOD SEAS BECOME DOMINATE. DS
EKA WATCHES/WARNINGS/ADVISORIES
CA...
NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
NONE.
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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