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County Warning Area [CWA]: STO Regional NWS Weather Office: Sacramento, CA 026 FXUS66 KSTO 112127 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 127 PM PST Wed Nov 11 2026 .KEY MESSAGES... - Dry weather, above normal temperatures, and periodically breezy north to east winds through Thursday - A series of storm systems will bring widespread rain, moderate to heavy rain and snow in the mountains, and gusty to strong southerly winds Friday into early next week - Winter Storm Watch in effect from Friday morning through Monday afternoon for the Sierra and Lassen National Park above 6000` - Wind Advisory is in effect from 4 am to 7 pm PST Friday for the northern Sacramento Valley and portions of the central Sacramento Valley && .DISCUSSION... ...Today through Thursday... A ridge will continue to remain in place across the area today into tomorrow, but slowly break down and shift east late Thursday. Dry conditions are expected with above normal temperatures across the area. Highs will be in the 70s across the area, with cooler conditions at the higher terrain. Breezy conditions at times within the higher terrain especially in the gaps and valleys. Potential for lower ceilings and patchy fog during the morning hours on Thursday as dew point depressions near zero across parts of the southern Sacramento Valley into the northern San Joaquin Valley. Visibility reductions to a couple miles will be possible at times especially near waterways. Winds will start to pick up late on Thursday and into the early morning hours on Friday as a trough digs into the southwestern United States. ...Friday and Saturday... The first of several storm systems moves into the region Friday through Saturday bringing mountain snow, rain, thunderstorms and windy conditions to the region. Rain will overspread the region Friday morning and coverage will only increase as we move throughout the day. Heavy rainfall rates are possible with stronger thunderstorms that develop in the afternoon and evening hours. Coverage of rain and thunderstorms start to diminish in the overnight hours, with isolated to scattered chances within the mountains and isolated within the Valley. Total forecasted rainfall will be 0.25 to 1 inch within the Valley, up to 2 inches within the mountains and foothills. Isolated higher amounts are possible especially where stronger storms develop. Latest HIRES guidance has the slight potential for a SCCZ developing during the evening hours on Friday. However, confidence is low on placement, duration, development, and how long one may set up. Increased low level moisture, instability, and wind shear will help develop a few thunderstorms across the Valley/Foothills during the afternoon and evening hours. A few storms may be on the stronger side as noted within atmospheric soundings across the Valley/Foothills. Strong elongated shear, instability up to 400 J/kg, and synoptic support will help initiate thunderstorms for the Valley/Foothills as the system moves onshore across the area. Impacts from stronger storms would be heavy rainfall rates, frequent lightning, gusty winds, and small hail. On top of the rain and thunderstorm chances there will be the strong southerly winds that develop during the morning and afternoon hours on Friday. A Wind Advisory is in effect for parts of the northern Sacramento Valley and central Sacramento Valley from 4am Friday through 7pm Friday due to the strong southerly winds. Gusts up to 45 mph are expected within the Advisory area, with up to 35 mph elsewhere. Strong winds within the mountains as well. There is a chance for an extension to the Advisory to incorporate the southern Sacramento Valley and into parts of the Delta, but confidence is low on how strong winds will be within those areas for Friday. Right now probabilities to see above 40mph wind gusts are 40 percent within the Delta and 30 percent within the southern Sacramento Valley. We will continue to monitor the need for any extension on Friday to incorporate the southern Sac Valley and into the Delta. Now for the snow chances within the higher terrain, snow levels continue to trend lower. Snow levels will be 6500-7500 ft Friday and drop to 5500-6500 feet by Saturday morning. Snow will be heavy at times, with strong winds creating potential white out conditions. Travel could be very difficult during this time impacting the Friday evening and Saturday commutes. A lull in activity is expected Saturday afternoon and evening as the first system moves out of the region and the second moves into CA Saturday night. ...Sunday and Beyond... Lull in activity is expected Saturday afternoon/evening, with the secondary system moving in Saturday night in Sunday. Precipitation coverage becomes widespread once again across the area Sunday throughout the day. A slight chance for an afternoon thunderstorm is possible, but instability is on the lower end along with shear at this time. Rainfall may be moderate at times within the mountains, foothills, and Valley. Coverage will start to diminish along with rain intensity as we move into Monday. The Valley precip chances start to clear out slowly by the late afternoon and evening, with lingering precipitation in the mountains through Tuesday morning. Up to 2 inches of QPF will be possible within the higher terrain Sunday through Tuesday morning. Areas within the Valley will see up to an inch of QPF. Snow levels during this time will be in the 6500-7500 feet Sunday afternoon and drop to 5500-6500 feet Monday morning. Snow will be heavy at times, with reductions to visibility. Travel may be very difficult for the Monday commutes. Looking at both systems together, up to 2 feet will be possible at higher peaks from Friday through Monday. Minor accumulations of up to an inch are possible down at 5000 feet. A Winter Storm Watch is in effect from Friday morning through Monday afternoon for the northern Sierra above 6000 feet, including Highway 50, I-80, the southern Cascades, and Lassen National Park. Another lull in activity is expected Tuesday morning and afternoon, with the potential for the active pattern to continue. There is a potential for further systems mid to late next week bringing more precipitation to the area. Uncertainty arises with the timing, development, and strength of these systems. && .AVIATION... VFR conditions are expected through the TAF period, with locally MVFR around the Sacramento Sites and SCK 12z through 17z for low ceilings and visibility. There is the slight chance for patchy morning fog tomorrow as winds remain light and variable across the Valley. Otherwise, skies will be mostly clear through the remainder of today and into tomorrow. && .STO WATCHES/WARNINGS/ADVISORIES... Wind Advisory from 4 AM to 7 PM PST Friday for Butte County Below 1000 ft-Central Glenn Co & Interstate 5-Eastern Glenn County-N. Sac Valley in Tehama County-Shasta Metro. Winter Storm Watch from Friday morning through Monday afternoon for Lassen Volcanic NP-Sierra (Cal-Tuo) Above 6000 ft-Sierra (El Dorado-Amador) Above 6000 ft-Sierra (Sierra-Placer) Above 6000 ft. && $$
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