974
FXUS66 KEKA 090716
AFDEKA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EUREKA CA
1216 AM PDT THU APR 9 2026
SYNOPSIS
WET AND UNSETTLED WEATHER WITH SHOWERS AND C
THUNDERSTORMS WILL CONTINUE THURSDAY THROUGH FRIDAY. SIGNIFICANT
COOLING, MORE RAIN, POSSIBLE THUNDERSTORMS AND HIGH MOUNTAIN SNOW
ARE ANTICIPATED FOR THIS UPCOMING WEEKEND.
KEY MESSAGES
-ISOLATED TO SCATTERED THUNDERSTORMS WILL OCCUR OVER THE REGION
THURSDAY AFTERNOON AND EVENING AND AGAIN FRIDAY.
-THE ENVIRONMENT WILL BE FAVORABLE FOR SOME MARGINALLY SEVERE
THUNDERSTORMS CAPABLE OF HEAVY RAINFALL, STRONG WIND GUSTS AND
LARGE SIZED HAIL FOR THURSDAY AFTERNOON AND EVENING.
-THUNDERSTORM MOTION WILL FAVOR "TRAINING" CELLS MOVING OVER THE
SAME AREA, INCREASING THE CHANCE FOR LOCALIZED FLASH FLOODING.
-THE BEST CHANCES FOR THE LISTED HAZARDS ARE OVER TRINITY, HUMBOLDT
AND DEL NORTE COUNTIES, THOUGH THUNDERSTORM CHANCES COVER THE ENTIRE
FORECAST AREA THROUGH LAKE COUNTY.
-ISOLATED TO SCATTERED THUNDERSTORMS ARE FORECAST AGAIN FRIDAY,
WITH ADDITIONAL CHANCES FOR SOME STRONGER CALIBER STORMS FOR THE
REGION.
DISCUSSION
A CLOSED LOW APPROACHING N CA BROUGHT AND ACTIVE
THUNDERSTORM DAY WEDNESDAY. SPC MESOANALYSIS DEPICTED SURFACE CAPE
UP TO 1500 J/KG THROUGH THE AFTERNOON, AND AS A RESULT SOME
THUNDERSTORMS APPROACHED MARGINALLY SEVERE CRITERIA WITH GUSTS
LIKELY NEAR 50 MPH. THIS PLACES THE FORECAST ON TRACK.
A GREATER RISK FOR THUNDERSTORMS IS ON TRACK FOR THURSDAY
AFTERNOON AND EVENING ACROSS NW CA, WITH A FOCUS OF STRONGER
STORMS LIKELY OVER NORTHERN HUMBOLDT, DEL NORTE, AND TRINITY
COUNTIES. FORECAST SOUNDINGS INDICATE SUFFICIENT BUOYANCY AND
STEEP MIDLEVEL LAPSE RATES TO SUPPORT SCATTERED THUNDERSTORMS
CAPABLE LARGER HAIL AND STRONG WIND GUSTS. MARGINALLY SEVERE HAIL
IN THE 1/2 INCH TO 3/4 INCH RANGE AND WIND GUSTS OF 40 TO 50 MPH
WILL BE POSSIBLE WITH STRONGER STORMS. LOCALLY HIGHER-END IMPACTS,
INCLUDING HAIL UP TO 1 INCH AND WIND GUSTS APPROACHING 60, MAY
OCCUR WITH THE MORE VIGOROUS DISCRETE CELLS. TRAINING CELLS AND A
LOCALIZED FLASH FLOODING THREAT MAY BECOME A STANDOUT THREAT,
ESPECIALLY WITH PRECIPITABLE WATER VALUES OF 0.8 TO 0.9 INCH,
LOCALLY NEAR 1.0 INCH. CAMS ARE OUTPUTTING SOME HIGHER END
RAINFALL AMOUNTS LOCALLY WHERE TRAINING MAY OCCUR.
AS THE LOW PUSHES CLOSER TO THE COAST IN THE AFTERNOON, EFFECTIVE
SHEAR IN THE 30 KT AND UP TO NEAR 40 KT RANGE MAY ALLOW FOR SOME
ORGANIZED CLUSTERS AS OUTFLOW INTERACTIONS INCREASE. WHILE THE
OVERALL TORNADO SIGNAL REMAINS WEAK (LESS THAN 5% CHANCE), LOCALIZED
ENHANCEMENTS IN LOW-LEVEL SHEAR NEAR THE SURFACE LOW MAY SUPPORT A
BRIEF, WEAK FUNNEL, PARTICULARLY ACROSS FAR NORTHERN HUMBOLDT AND
EASTERN DEL NORTE COUNTY WHERE TERRAIN AND BOUNDARY INTERACTION
COULD LOCALLY AUGMENT ROTATION. QUICKER STORM ORGANIZATION WOULD
FURTHER LIMIT THIS THREAT. THE PROGRESSING LOW WILL GENERATE SOME
BREEZY SOUTHERLY WINDS FRIDAY AFTERNOON FOR THE SOUTHERN ZONES
THROUGH SOUTH MENDOCINO AND LAKE COUNTIES.
BEYOND FRIDAY INTO NEXT WEEKEND, WET AND COOLER WEATHER RETURNS ON
SATURDAY AS AN UPSTREAM AND MUCH COLDER TROUGH AND CLOSED LOW
COMES BARRELING DOWN FROM THE NW AND KICKS/ABSORBS THE FIRST LOW.
MOST ALL THE MODELS HAVE TRENDED MUCH WETTER FOR THIS STORM
SYSTEM, WHICH WILL INCLUDE HIGH MOUNTAIN SNOW AND A PERIOD OF
GUSTY TO PERHAPS LOCALLY STRONG SOUTHERLY WINDS AROUND AND SOUTH
OF CAPE MENDOCINO AND THROUGH LAKE COUNTY. NBM CHANCES FOR OVER
AN INCH OF RAINFALL IN 24 HOURS ARE HIGH FOR MUCH OF THE REGION
(60-80%). CHANCES FOR OVER 2 INCHES ARE ALSO HIGH IN THE KING
RANGE AND THE MOUNTAINS OF DEL NORTE AND SOUTHERN TRINITY. THIS
LOW LOOKS TO BE QUITE DYNAMIC REGARDING FORCING AND ASSOCIATED
INSTABILITY. A CONVECTIVE BAND OR LINE OF MODERATE TO LOCALLY
HEAVY RAINFALL AND SOME THUNDERSTORMS WILL BE POSSIBLE, ESPECIALLY
GIVEN THE PRECEDING SATURATED COLUMN AND HIGH PRECIPITABLE WATER
VALUES.
SNOW LEVELS DROP TO AROUND 3500 TO 4000 FT BY SATURDAY NIGHT. NBM IS
SHOWING AROUND A 50% CHANCE FOR OVER 4" OF SNOW ON HIGHWAY 3 AT
SCOTT MOUNTAIN PASS AND A 25% CHANCE ON HIGHWAY 36 AT SOUTH FORK
MOUNTAIN. COLD TEMPERATURES ALOFT COULD SUPPORT INSTABILITY NEAR THE
COAST, BRINGING SHOWERS WITH THUNDERSTORMS AND POSSIBLY SOME SMALL
HAIL. THIS WILL NEED TO BE WATCHED AS WE GET CLOSER TO THIS EVENT.
NBM HAS MODERATE CHANCES (45%) FOR SNOW LEVELS BELOW 3500 FT LATE
SATURDAY THROUGH SUNDAY. COLDER LEVELS ARE POSSIBLE DEPENDING ON THE
TRACK OF THE LOW.
MUCH COLDER TEMPERATURES ARE LIKELY DURING AND AND BEHIND THIS
FRONTAL PASSAGE. NEAR-FREEZING TO SUB-FREEZING TEMPERATURES ARE
FORECAST, ESPECIALLY SUNDAY AND MONDAY MORNINGS. STAY TUNED TO
OUR LATEST FORECAST FOR MORE DETAILS AND POSSIBLE WATCHES,
WARNINGS AND ADVISORIES. JJW
AVIATION
ISOLATED SHOWERS CONTINUE TO MOVE THROUGH THE AREA
EARLY THIS MORNING. SOME OF THE HEAVIER SHOWERS MAY BRING MVFR
CONDITIONS. THERE IS QUITE A BIT OF MOISTURE AROUND SO IT IS
POSSIBLE SOME FOG OR LOW CLOUDS WILL FORM EARLY THIS MORNING.
HOWEVER, EITHER THESE SCENARIOS ARE EXPECTED TO BE FAIRLY
SHORTLIVED. A AROUND OF STRONGER SHOWERS AND POSSIBLE THUNDERSTORMS
IS EXPECTED STARTING MIDDAY ON THURSDAY. SOME OF THESE THUNDERSTORMS
COULD BRING GUSTY WINDS AND POSSIBLE HAIL. TONIGHT, EXPECT THE
SHOWERS WILL DIMINISH BOTH IN STRENGTH AND COVERAGE. MKK
MARINE
AN AREA OF LOW PRESSURE IS APPROACHING THE AREA AND THIS
IS STARTING TO SWITCH THE SOUTHERN WATERS TO SOUTHERLY WINDS WHILE
FARTHER NORTH THEY REMAIN NORTHERLY. THIS GENERALLY CONTINUES
THROUGH THURSDAY NIGHT. FRIDAY SOUTHERLY WINDS START TO INCREASE TO
AROUND 5 TO 10 KT ACROSS THE AREA. BOTH DAYS THERE IS THE POTENTIAL
FOR THUNDERSTORMS BRINGING LOCALLY STRONGER WINDS AND POSSIBLY SMALL
HAIL.
THERE ARE SOME SMALL SWELLS MOVING THROUGH THE WATERS, BUT THESE ARE
GENERALLY
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. MONDAY HIGH PRESSURE STARTS TO BUILD INTO THE AREA
AND MODERATE TO STRONG NORTHERLY WINDS RETURN. 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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