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000 FXUS66 KSTO 192006 AFDSTO Area Forecast Discussion National Weather Service Sacramento CA 106 PM PDT Sun Apr 19 2026For additional details on weather and expected impacts over the next 7 days, please visit weather.gov/sto/briefing.KEY MESSAGES
- Dry weather with near to slightly above normal temperatures today
- Storm system brings renewed precipitation chances in moderate to heavy rain and mountain snow, thunderstorms, cooler temperatures and breezy winds Monday through Wednesday
- Winter Storm Watch in effect from late Monday night through Wednesday afternoon
DISCUSSION
..Today
Current GOES-West visible satellite imagery shows mostly to partly sunny skies across interior northern California. The incoming storm system can be seen on satellite over the eastern Pacific ocean. Dry and warm weather will prevail across the area today. Forecast highs are in the 70s to low 80s in the Valley and foothills, and in the 50s to 60s in the mountains. These temperatures will be trending near to slightly above normal for this time of year. Southerly winds will gradually be increasing through the day today as the storm system continues to approach the region and bring impacts early to mid this week.
..Monday through Wednesday
The upper level pattern will feature a low moving into California bringing stormy conditions Monday through Wednesday of this week. This storm will bring widespread rain, mountain snow, thunderstorms, breezy south to southwest winds, and cooler temperatures to interior northern California. Rain and snow will be moderate to heavy at times, especially on Tuesday which is looking like the brunt of the storm. A Winter Storm Watch has been issued for the Sierra Nevada and southern Cascades above 5000 feet from late Monday night through Wednesday afternoon. Snow levels will initially be around 6000-7000 feet Monday night, lowering to 5500-6500 feet Tuesday and then down to 4500-5500 feet on Wednesday. Mountain travel delays, chain controls, reduced visibilities and snow covered roads are all possible.
For the lower elevations, rainfall will begin Monday and continue through Wednesday with the heaviest on Tuesday. This will lead to impacts such as slick roads, ponding of water on roadways, and rises on creeks and streams. In addition to rain there is also the threat for thunderstorms on Tuesday and Wednesday. Scattered thunderstorms on Tuesday have the best chances for strong to severe thunderstorm development. Potential hazards with these thunderstorms that develop include lightning, gusty winds, heavy rain, hail, funnel clouds and isolated weak tornadoes. Precipitation tapers off late Wednesday. Check back frequently for updates on this storm and always check the forecast and road conditions before traveling!
..Thursday through Saturday
Mostly dry weather returns to the region on Thursday behind the passage of the storm system. Ensemble guidance is indicating the potential for some additional mountain showers late in the week and into next weekend with generally light precipitation. Temperatures warm back up closer to normal for late April climatology.
AVIATION
General VFR conditions at TAF sites over the next 24 hours. Increasing cloud cover around 00z Monday as a weather system moves into the area, but no changes in flight categories in the next 24 hours. Southerly winds with gusts up to 25 kts in the northern Sacramento Valley and foothills, and up to 30 kts in the mountains through 06z Monday, then winds generally less than 12 kts everywhere.
STO WATCHES / WARNINGS / ADVISORIES
Winter Storm Watch from late Monday night through Wednesday afternoon for Lassen Volcanic National Park-Sierra Nevada of Calaveras-Tuolumne-Southern Alpine Counties Above 5000 ft-Sierra Nevada of El Dorado-Amador-Northern Alpine Counties Above 5000 ft Including Highway 50-Sierra Nevada of Sierra-Nevada-Placer Counties Above 5000 ft Including Interstate 80-Sierra Nevada of Tehama-Butte-Plumas Counties Above 3000 ft.