March 4, 2018 – Lingering light snow showers possible over the mountains today. A brief drying out period early next week will be followed by a return of precipitation mid to late week.
Dense fog has developed over portions of the Sacramento Valley this morning with current visibilities been reported less than one quarter mile. Latest high resolution guidance indicates reduced visibilities continuing this morning with improving conditions in the late morning. Thus, a Dense Fog Advisory is in effect through 11 am. Drivers will experience rapidly changing visibilities on area roadways this morning. This impact portions of I-80 and I-5 near the Sacramento area and surrounding communities. No further updates needed.
Discussion (Today through Wednesday)
Latest radar imagery indicates heavier snow shower activity shifting east of the Sierra crest. Lingering light showers are possible through this morning over the Sierra the rest of the morning. Little or no additional snow accumulation is expected, so the Winter Storm Warning has been cancelled. Light snow showers are possible through the afternoon over the mountains north of I80 through the rest of the day. Elsewhere, dry weather is expected. Some patchy fog is developing in portions of the northern San Joaquin Valley and Mother Lode this morning. A bank of low stratus clouds could linger through the morning hours over the northern and central Sacramento Valley, with clearing by afternoon.
Upper level ridging will build across the area bringing dry conditions across the area into mid week. Daytime highs will be cool today, but are expected to trend upward through mid week, reaching slightly above seasonal normals on Tuesday and Wednesday with Valley and Delta highs in the mid to upper 60s, lower 60s in the foothills, and 40s and 50s over higher terrain.
The next wet system could start to spread into the northern Coastal Range as early as Wednesday afternoon, reaching the I80 corridor late Wednesday night. Snow levels with this system would initially be around 5500 feet for the southern Cascades, 6500 feet over the northern Sierra. Snow amounts into early Thursday are currently are expected to be generally be an inch or less.
Extended discussion (Thursday through Sunday)
Precipitation chances return after mid-week as ridging shifts east allowing a series of quick-moving systems to thru NorCal Thursday and Friday. QPF is forecast to be lighter and snow levels higher than this past series of storms, so impacts expected to be less. Short-wave ridging returns next weekend for mainly dry weather.