Breezy with scattered mountain snow showers possible south of I-80 today. Cool and dry into the weekend with widespread freezing low temperatures in the early morning hours. Temperatures trend warmer towards the end of the week. Another round of unsettled weather possible early next week.
Discussion
3:00 am radar indicated the majority of the shower activity has pushed out of the region with only a few light snow flurries lingering over the Sierra, generally south of I-80. Temperatures this morning have cooled to near or below freezing for much of interior Northern California. Mountain locations are reporting temperatures in the single digits to 20s and the Valley and foothills are reporting temperatures generally in the 20s and 30s.
In addition to very cold air, a northerly to easterly breeze has developed in the wake of the departing system. The northern and western side of the Sacramento Valley as well as through wind prone drainage gaps in the Sierra foothills and over the Sierra crest, are seeing gusts generally reaching in to the 30 mph range, locally higher.
The breeze has helped to keep the temperature readings in those areas a tad warmer than nearby areas. However, due to the relatively dry and cool air in place, the breeze will make it feel cooler in those areas with current wind chill values dropping down into the 20s and 30s in the Sacramento Valley and single digits to teens in the foothills and mountains.
HRRR and NAM simulated reflectivity indicate the possibility for some lingering snow showers today over the Sierra south of I-80 with the remainder of the forecast area remaining dry. Breezy winds will also trend lower by the evening as gradients relax and high pressure rebuilds over northern California.
Very cold sub- freezing temperatures are expected in the early morning hours each day through Saturday. Thursday morning will likely be the coldest with a few locations nearing daily record low temperatures with widespread 20s expected in the Valley.
A hard freeze warning has been issued from 1 am to 9 am for the Central Valley and adjacent foothills below 2,000 feet for Thursday.
Temperatures this cold could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing. Please also make sure animals have adequate shelter from the cold.
Under high pressure, an inversion will set up in the Valley leading to areas along thermal belts trending warmer overnight as we get closer to the weekend with lows on Saturday in the foothills forecast to be slightly warmer than in the Valley.
Ensembles are in also agreement a shortwave will pass just to our north and east Thursday into Friday. Precipitation is not anticipated in our area and this feature will likely only lead to some passing clouds over Northern California.
Extended Discussion (Sunday through Wednesday)
Models are in good agreement with a shortwave moving through the north half of the forecast area. (Central Sac valley northward) on Sunday. Precipitation amounts are light so no major impacts are expected.
Beyond Sunday the models diverge and there is high uncertainty at this time. Cluster analysis does keep activity moving into the Pacific Northwest with maybe the tail end just skirting our northern areas to bring some precipitation on Monday and Tuesday. This is more supportive of the European model output. The GFS just moves a much weaker shortwave part us to the north during this time period. Expect changes in the forecast for next week.