412
FXUS66 KSTO 101839
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
1139 AM PDT FRI APR 10 2026
FOR ADDITIONAL DETAILS ON WEATHER AND EXPECTED IMPACTS OVER THE
NEXT 7 DAYS, PLEASE VISIT WEATHER.GOV/STO/BRIEFING.
KEY MESSAGES
- COOLER TEMPERATURES AND ACTIVE WEATHER THROUGH THE WEEKEND WITH
RAIN, STRONG TO SEVERE THUNDERSTORMS, GUSTY WINDS, AND
MOUNTAIN SNOW.
- WINTER STORM WARNING IN EFFECT FOR THE SIERRA AND SOUTHERN
CASCADES FRIDAY EVENING THROUGH SUNDAY EVENING.
DISCUSSION
..TODAY THROUGH THE WEEKEND
CURRENT UPPER AIR PATTERN HAS A 500MB TROUGH OFF THE COAST OF
CALIFORNIA MOVING ONSHORE TODAY AND THROUGH THE WEEKEND.
SOUTHERLY FLOW OF INSTABILITY AND MOISTURE HAS HELPED DEVELOP
SHOWERS AND STORMS WITHIN THE FORECAST AREA, WITH CONTINUED
CHANCES FOR STORMS THIS AFTERNOON AND EVENING. SOUNDINGS INDICATE
LOW LCL, CAPE INDICES AROUND 800-1500 J/KG, WEAK LOW LEVEL SHEAR,
AND LONG CAPE THROUGH THE ATMOSPHERE. THIS TYPE OF SET UP BRINGS
THE CHANCE FOR LARGE HAIL (1 INCH PLUS), ACCUMULATING HAIL, STRONG
WINDS, MODERATE RAINFALL RATES (LOCALLY HEAVY), AND BRIEF WEAK
TORNADOES.
CURRENTLY THIS MORNING, WE HAVE HAD A FEW PULSE/MULTI CELLULAR
STORMS DEVELOP ALONG THE FOOTHILLS/VALLEY WITH A REPORT OF
ACCUMULATING HAIL EAST OF THE ORVILLE, CA AREA. LATEST CAMS HAVE
CONTINUED DEVELOPMENT THROUGH THE REMAINDER OF THE AFTERNOON AND
EVENING, WITH THE PRIME TIME FOR THUNDERSTORM ACTIVITY THIS
AFTERNOON AND EARLY EVENING WHEN SPEED SHEAR, DIRECTIONAL SHEAR,
AND INSTABILITY IS AT ITS PEAK. CONTINUED CHANCES FOR STRONG TO
POTENTIAL SEVERE STORMS AGAIN SATURDAY AND INTO SUNDAY AS THE
UPPER LEVEL SYSTEM MOVES THROUGH CA. IF YOU ARE HEADED OUT, KEEP
AN EYE ON THE SKIES AND HAVE A WAY TO RECEIVE WATCHES, WARNINGS,
AND STATEMENTS TODAY AND THROUGH THE WEEKEND.
AS THE SYSTEM MOVES ONSHORE AND WE FILTER IN COOLER AIR ALOFT,
PRECIPITATION CHANGES OVER TO SNOW WITHIN THE MOUNTAINS. LATEST
NBM HAS KEPT THE FORECASTED SNOW TOTALS ROUGHLY THE SAME, WITH
SLIGHTLY LOWER SNOW LEVELS SUNDAY. A WINTER STORM WARNING IS IN
EFFECT FROM THIS EVENING THROUGH SUNDAY EVENING FOR ELEVATIONS
ABOVE 4500 FEET. SNOW LEVELS TODAY WILL BE ABOVE 6000 FEET AND
LOWER TOWARD 4000-5000 FEET BY SUNDAY. HEAVIEST SNOW RATES AND
LOWEST SNOW LEVELS ARE EXPECTED TO BE FROM SATURDAY AFTERNOON
THROUGH SUNDAY WHERE MAJOR IMPACTS TO MOUNTAIN TRAVEL ARE
ANTICIPATED. MOUNTAIN TRAVEL IS DISCOURAGED THIS WEEKEND. HEAVY
SNOWFALL RATES OF 1-2 INCHES PER HOUR ARE POSSIBLE WITHIN THE
SIERRA SATURDAY AFTERNOON THROUGH SUNDAY.
GUSTY SOUTHERLY WINDS ARE ALSO FORECASTED, WITH THE STRONGEST ON
SATURDAY. THE NORTH/CENTRAL SACRAMENTO VALLEY, NORTHEAST FOOTHILLS
AND SIERRA CREST WILL SEE THE STRONGEST WINDS OF 35-45MPH. WE
WILL CONTINUE TO MONITOR THE TRENDS IN THE FORECAST TO SEE IF A
PRODUCT WILL BE NEEDED FOR THE WINDS.
..NEXT WEEK
A RETURN TO DRIER AND WARMER TEMPERATURES EARLY TO MID NEXT WEEK
AS A RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION. HOW AMPLIFIED
THE RIDGE BECOMES IS UNCERTAIN AS LATEST GUIDANCE FROM THE NBM
SUGGESTS THE RIDGE FLATTENING OUT MID TO LATE WEEK. THIS WOULD
BRING THE CHANCE FOR ISOLATED SHOWERS AND A FEW SNOW SHOWERS
WITHIN THE MOUNTAINS. AMOUNTS, TIMING, AND DEVELOPMENT OF ANY
POTENTIAL SYSTEM MID TO LATE NEXT WEEK IS UNCERTAIN AT THIS TIME
WITH CONFIDENCE BEING LOW.
AVIATION
MVFR CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS,
WITH PERIODS OF IFR IN AND AROUND ANY THUNDERSTORM ACTIVITY.
SHOWERS AND STORMS WILL CONTINUE TO MOVE THROUGH THE REGION
THROUGH THE WEEKEND. WINDS, IN AND AROUND THUNDERSTORMS MAY BECOME
ERRATIC WITH DIRECTION CHANGES AND QUICK SPEED CHANGES.
OTHERWISE, SURFACE WINDS WILL BE OUT OF THE SOUTH FOR SITES AROUND
SACRAMENTO THROUGH RDD AND RBL. MOD AND SCK WILL SEE WINDS OUT OF
THE NW. SURFACE WINDS WILL BE AROUND 10-12KTS, WITH PERIODIC
GUSTS TO 20KTS IN RDD AND RBL. WINDS WILL BE ON THE STRONGER SIDE
TOMORROW IN THE NORTHERN SACRAMENTO VALLEY, WITH GUSTS UP TO 45MPH
AT TIMES.
STO WATCHES/WARNINGS/ADVISORIES
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 11 PM PDT
SUNDAY FOR WEST SLOPE NORTHERN SIERRA NEVADA-WESTERN PLUMAS
COUNTY/LASSEN PARK.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page