Cool mornings and short periods of dry weather with morning fog are expected over the next few days. A major mountain trip is expected over the weekend, with rain returning over the weekend. Very difficult travel conditions with chain restrictions and possible road closures. Low visibility due to combination of wind and heavy snow.
Skies have cleared over much of the interior of Norgal as the low pressure has moved southeast of the area. Snow points will be in the mid to upper 30s across the Central Valley, with generally light winds and more snow cover than snow. IR contrast images already show haze forming along the eastern edge of the valley from east of Sacramento to the San Joaquin Valley. Fog can be more extensive and dense locally in this area around sunrise, but lifts around midnight.
A short wave of waves will bring a short period of dry weather today and early Thursday. Clouds are already increasing tonight, which should help keep things a bit warmer but still cooler, but also reduce the chance of fog.
An upper-level trough will push north of the area late Thursday through early Friday morning. Chances of rain begin Thursday afternoon in the northern part of the region, then continue to spread south through the evening and night. The best forcing will be in the northern regions, where the highest QPF can be expected in this system.
Snow levels are light in the 3000 to 4000 ft range and accumulate above 3500 ft. Generally 5-10″ seen from I-80 north, with some higher amounts locally on the higher peaks.
A winter weather advisory is in effect. Friday through Saturday will be a high-impact trough before turning into a flow zone again on Friday.
We should see a break in the rain from mid-afternoon on Friday. A warm wind will develop precipitation Friday afternoon through night.
On Saturday, heavy rainfall is expected along with strong southerly winds along the Main Valley and a cold front.
Extended Discussion (Sunday to Wednesday)
Showers on Sunday as a post-cool upper low moves into inland Norcal. Heavy snow continues into the Sierra Nevada early Sunday morning. With Monday’s lingering rain, there are model differences in how quickly it moves out of the low, mainly in the Sierra Nevada. Models dry out under upper ridges through midweek. Below normal high temperatures expected over the extended period.