125
FXUS66 KEKA 080827
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
127 AM PDT WED APR 8 2026
SYNOPSIS
WET AND UNSETTLED WEATHER WITH SHOWERS AND A CHANCE
OF THUNDERSTORMS IS EXPECTED WEDNESDAY THROUGH FRIDAY. SIGNIFICANT
COOLING, MORE RAIN, POSSIBLE THUNDERSTORMS AND HIGH MOUNTAIN SNOW
ARE ANTICIPATED FOR THIS UPCOMING WEEKEND.
DISCUSSION
AN APPROACHING CLOSED 500MB LOW IS TRACKING EAST
NEARING THE CALIFORNIA COAST WEDNESDAY. THE LOW HAS TAPPED INTO SOME
SUBTROPICAL MOISTURE, BRINGING PRECIPITABLE WATER VALUES 200% OF
NORMAL. WITH SURFACE CAPE RAMPING UP IN THE INTERIOR (SOME MODELS
NEAR 1000J/KG), AND SURFACE BASED LIFTED INDICES NEAR -3C TO -2C,
STRONGER AND MORE WIDESPREAD THUNDERSTORM ACTIVITY APPEARS
POSSIBLE WED AFTERNOON INTO EARLY EVENING IN THE INTERIOR - MOSTLY
IN TRINITY COUNTY. THERE IS TYPICALLY A DELAY IN SURFACE
SATURATION, EVIDENT BY INVERTED V PROFILES EARLY IN THE AFTERNOON
OVER TRINITY COUNTY. THIS WILL SUPPORT SOME STRONG TO MARGINALLY
SEVERE DOWNDRAFT WIND GUSTS. SOUNDINGS DEPICT DCAPE VALUES UP TO
600 J/KG, FURTHER EMPHASIZING THE THREAT, WHICH INCLUDES SMALL
HAIL AND EVENTUAL LOCALLY HEAVY RAINFALL AFTER THE LOWER- LEVELS
SATURATE AND PRECIPITABLE WATER VALUES REACH UP TO 0.9 INCHES.
THE LOW BRUSHES CLOSER TO THE NORTH COAST THURSDAY WHEN HIGHER
CHANCES FOR SHOWERS AND THUNDERSTORM (25-35%) DEVELOP AS A RESULT.
BROAD FORCING MAXIMIZES LATE THURSDAY AROUND THE LOW WITH
ADDITIONAL MESOSCALE VORTICITY MAXIMUMS ROTATING IN, AND SURFACE-
TO- 500MB S-SE BULK SHEAR (25-35KT) SHEAR INCREASING TO 25 TO 35
KTS. SOUTHEAST STEERING FLOW WILL ALLOW FOR INTERIOR, POSSIBLY
ORGANIZED STORM CLUSTERS TO ATTEMPT TO PROPAGATE WESTWARD TOWARD
THE COAST. THE THERMODYNAMIC PROFILE SUPPORTS HAIL GROWTH, WITH
STEEP MID-LEVEL LAPSE RATES REACHING 7.3 C/KM. HODOGRAPHS ON
OCCASION SHOW SOME ROUNDING, ESPECIALLY LATE THURSDAY AFTERNOON
AND EVENING THROUGH FAR NORTHERN INTERIOR HUMBOLDT THROUGH DEL
NORTE AND THROUGH THE OREGON BORDER. THIS POTENTIAL LOWER LEVEL
ROTATION IS ALSO CAPTURED WITH 0-3KM SRH, WHICH COINCIDES WITH
SOME POTENT LOOKING VORTICITY MAXIMUMS. THIS PERIOD WILL HAVE TO
BE WATCHED CLOSELY FOR SOME STRONGER THUNDERSTORMS CAPABLE OF AT
LEASE SOME BRIEF ROTATION. THE ACTION CONTINUES FRIDAY WITH A
SIMILAR STORM TRACK FAVORABLE TO WESTWARD COASTAL PROPAGATION.
BEYOND FRIDAY INTO NEXT WEEKEND, WET AND COOLER WEATHER RETURNS ON
SAT OR SAT NIGHT AS AN UPSTREAM AND MUCH COLDER TROUGH AND CLOSED
LOW COMES BARRELING DOWN FROM THE NW. MOST ALL THE MODELS HAVE
TRENDED MUCH WETTER FOR THIS STORM SYSTEM, WHICH WILL INCLUDE
HIGH MOUNTAIN SNOW AND A PERIOD OF GUSTY WINDS. THERE IS HIGH
UNCERTAINTY ON WHERE THE CLOSED LOW ENDS UP COMING ASHORE, THUS
THERE IS A WIDE RANGE IN ENSEMBLE MEMBERS FOR TOTAL RAINFALL
AMOUNTS. OVER HALF OF THE ENSEMBLE MEMBERS HOLD 1 TO 2.4 INCHES
FOR 24 HOUR RAINFALL TOTALS SATURDAY THROUGH SUNDAY FOR THE NORTH
COAST. NBM 90% SHOWS 0.50 TO 1.50 INCHES FALLING IN 12 HOURS.
THIS WOULD BE PLAUSIBLE IF THE LOW TAKES A MORE SOUTHERN TRACK AS
IT QUICKLY MOVES INTO A SATURATED AIRMASS LEFT FROM THE KICKED
PREVIOUS LOW. HIGHER AMOUNTS MAY BE POSSIBLE FOR THE INTERIOR, AND
TOTAL RAINFALL WOULD BE LOWER WITH A MORE NORTHERN TRACK. SNOW
LEVELS CURRENTLY LOOK TO DROP TO 4000 FEET THROUGH THIS PERIOD,
BUT LOWER LEVELS ARE POSSIBLE.
THUNDERSTORMS ARE POSSIBLE WITH THIS COLD SYSTEM SATURDAY
THROUGH SATURDAY NIGHT. 700 TO 850 MB TEMPERATURES LOOK NEARLY COLD
ENOUGH TO SUPPORT SMALL HAIL AND POSSIBLE TRAVEL IMPACTS IF LOW
LEVEL TEMPERATURES ARE COOL ENOUGH OVERNIGHT SATURDAY. MUCH COLDER
SURFACE TEMPERATURES WILL ARRIVE BEHIND THE PASSING OF THE LOW.
LATE SEASON COASTAL FROSTS AND INTERIOR FROSTS AND FREEZES WILL BE
POSSIBLE SUNDAY MORNING AND INTO EARLY NEXT WEEK. STAY TUNED TO
OUR LATEST FORECAST FOR MORE DETAILS AND POSSIBLE WATCHES,
WARNINGS AND ADVISORIES.
AVIATION
THE MARINE LAYER IS IN PLACE ALONG THE COAST BRINGING
IFR TO MVFR CONDITIONS. AN UPPER LEVEL LOW APPROACHING THE AREA THIS
MORNING IS EXPECTED TO LIFT CEILINGS AT SOME POINT DURING THE
MORNING TO VFR. THE TIMING IS UNCERTAIN ON WHEN THIS WILL OCCUR.
LATER THIS AFTERNOON AND EVENING AS THE UPPER LOW APPROACHES THE
AREA THERE IS THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS. THESE ARE
MAINLY EXPECTED TO BE OVER TRINITY COUNTY, BUT A FEW COULD MAKE IT
AS FAR WEST AS THE COAST. SO THIS WILL NEED TO BE MONITORED. THESE
SHOWERS WILL BRING LOWER CONDITIONS, BUT THESE ARE EXPECTED TO BE
FAIRLY LIMITED IN COVERAGE. MKK
MARINE
NORTHERLY WINDS ARE AROUND 5 TO 10 KT ACROSS THE WATERS.
THE WAVES REMAIN SMALL AS WELL WITH SEVERAL SWELLS, BUT ALL OF THEM
LESS THAN 3 FEET. AN AREA OF LOW PRESSURE IS EXPECTED TO APPROACH
CAPE MENDOCINO WEDNESDAY AFTERNOON. THIS IS EXPECTED TO SWITCH THE
SOUTHERN WATERS TO SOUTHERLY WINDS WHILE FARTHER NORTH THEY REMAIN
NORTHERLY. THIS GENERALLY GENERALLY CONTINUES INTO FRIDAY WITH THE
LOW MOVING VERY SLOWLY. WINDS ARE GENERALLY EXPECTED TO REMAIN BELOW
10 KT.
FOR THE WEEKEND A STRONGER AREA OF LOW PRESSURE IS EXPECTED AND THIS
HAS THE POTENTIAL TO BRING STRONGER WINDS. THE STRENGTH, TIMING AND
LOCATION REMAIN HIGHLY UNCERTAIN DUE TO LOW CONFIDENCE ON THE TRACK
OF THE LOW. MKK
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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