December 29, 2018 – Dry through the middle of next week except for isolated showers over the northern mountains on Sunday. Breezy north winds again early next week.
Mainly clear skies across the region early this morning under northerly flow on the backside of the trough. Northerly gradients are weaker and winds are considerably lighter across much of the area.
Current temperatures are colder compared to 24 hours ago and range from the upper single digits and teens in the mountain valleys to the 30s to lower 40s elsewhere.
Dry pattern continues through early next week. Late night and early morning temperatures will continue to be chilly with mainly clear skies, a dry airmass and lighter winds while daytime highs will be relatively mild.
The next short-wave, presently entering the Gulf of Alaska, will drop southward to our east following a similar track to the last one. Some clouds will be possible, but shower chances are expected to remain to the east of the Sierra crest on Sunday.
Breezy/windy weather returns Monday and continues into New Year`s (though not as strong) as gradients increase across NorCal in the wake of the system dropping down into the Desert Southwest.
Strongest winds are expected along the western edge of the Sacramento Valley, across Lake County and over the higher ridges of the northern Sierra Nevada.
Extended Discussion (Wednesday through Saturday)
On Wednesday morning, broad upper ridging will expand over the region as the leading closed low continues to pull away from the Desert Southwest. Overall pressure and height gradients weaken which will decrease winds considerably relative to earlier in the week.
This ridge should remain in place through Thursday before moving inland in response to the next system lurking over the Pacific. Models remain at odds with timing and amplitude but increasing clouds are likely by Friday into the weekend in advance of this approaching trough. This will ultimately help raise some of the Valley temperatures after a series of chilly mornings.
A much more defined system could materialize over the weekend which would afford a return of precipitation chances across the region. However, this is still 8 days away so much can change in the model guidance.