May 1, 2018 – Drier and warmer this week except for a few showers and thunderstorms over the Sierra through Wednesday.
Discussion
Variable cloudiness prevails across interior Northern California early this morning as a strong short-wave off the coast continues to dig the trough toward SoCal. Current temperatures are in the 30s and 40s in the mountains, and in the upper 40s and 50s through the Central Valley.
Northerly flow will increase today as we’ll be on the backside of the trough. Locally breezy conditions are expected through the Central Valley as surface gradients tighten (MFR-SAC is already over 8 mbs). A last batch of short-wave energy is forecast to slide southward keeping a chance for a few showers in the Sierra south of Lake Tahoe. Temperatures will warm around 5-10 degrees compared to Monday as the airmass moderates.
Further warming and drying takes place through the rest of the week as ridging from the eastern Pacific takes hold. Highs Thursday and Friday are expected to be in the 80s through the Central Valley.
Extended discussion (Saturday through Tuesday)
An upper level trough moving through the forecast area will bring possible showers over the northern mountains on Sunday. Only light accumulations are expected. Drier weather is expected by Monday as trough axis shifts east of the forecast area, and ridging rebuilds into NorCal. Daytime highs expected to remain several degrees above seasonal normals through the period. Valley locations could reach the 90s by the end of the forecast period.