Dry conditions through Tuesday before a weather system moves in midweek bringing mountain snow, widespread rain, breezy winds, and thunderstorm chances.
Discussion
Our weather system from the last several days has ceased with drier and warmer weather the main impacts early this week. Snow analysis estimates 8-24 inches, up to 36 inches fell across the Sierra with 4 to 12 inches in the Coastal Range area from Friday to Sunday morning. Precipitation amounts were 0.25-1.00″ in the Valley with 0.50-1.50″ across the foothills and Northern Sacramento Valley, including Redding.
Afternoon highs warm to the 60s to low 70s in the Valley, with 50s to 60s in the foothills, and 40s to 50s in the mountains. A few light showers and snow showers will be possible over the foothills and mountains on Monday, however little to no impacts are expected with this.
Another storm system will move into the region on Wednesday into the weekend, bringing renewed chances for widespread precipitation, mountain snow, breezy winds, and isolated thunderstorms. The National Blend of Models (NBM) forecasts a 40-80% chance of snow amounts exceeding 6 inches above 5500 feet from Wednesday through Thursday night, with highest chances along higher elevations north of I-80.
For rain probabilities, the NBM shows a 40-95% chance of exceeding 0.25″ across much of the Valley, increasing as you travel northward.
The NBM also projects a 50-95% chance of southerly wind gusts greater than 40 mph on Wednesday, mainly in the wind prone areas such as the northern/central Sacramento Valley, adjacent foothills, and Sierra Nevada.
Additionally, confidence is low in exact strength, timing, and location but there is a chance (10-15%) we see a repeat of isolated thunderstorms Wednesday and Thursday across the Valley and foothills in the afternoon and evening hours.
Wednesday is forecasted to be the heavier precipitation of the two days. Potential impacts include slick roads, and mountain travel delays with chain controls. Periods of active weather continue into the extended forecast period as well.
Extended Discussion (Friday through Monday)
Active weather continues on Friday and through much of the weekend as the trough sinks into SoCal. Clusters are in relative agreement with the movement of the weather system, although there is some minor disagreement on the strength of the trough as it moves over SoCal.
There continues to be around a 20-50% chance of 12 inches of new snow or more over the higher Sierra elevations Friday and Saturday. Thunderstorm chances remain in the forecast for Friday and Saturday.
Both days depict a 10-15% chance with Saturday having the greater area extent of thunderstorm chances.
Precipitation amounts remain highly uncertain at this time due to the current path models are forecasting and possible convection. Generally amounts look to be under 0.50″ for the Valley and between 0.50-1.50″ for the foothills and mountains but locally thunderstorms could result in higher totals. By Sunday the low is centered well south of the area. Some shower chances remain generally south of I-80 but the interior should be mostly dry this far north.
Cooler than normal temperatures are expected Friday by mostly 5 to 15 degrees with the greater departure from normal conditions occurring in the mountains.
Warming over next weekend becoming close to above normal temperatures by early next week with temps in the upper 60s, low 70s in the Valley.