July 4, 2019 – Temperatures gradually warm to slightly above average by the weekend then cool slightly for the start of next week. Breezy wind at times through the Delta and over the Sierra crest.
Discussion
Clear skies cover the region early this morning. Current temperatures range from the lower 40s in the mountain valleys to the upper 50s to around 70 across the Central Valley.
Gradual warming will continue into the weekend as the persistent weak trough along the West Coast weakens. Temperatures today will be within a degree or two of average, then will be several degrees above average on Friday and Saturday. Cooling is expected to return Sunday as another closed low moves into the PacNW reinforcing the trough along the coast.
Extended Discussion (Monday through Thursday)
The forecast for next week starts cool as a rather dry shortwave passes through and exits to the east late in the day. Any precipitation will stay to the north of interior Northern California. Temperatures will then trend gradually upwards starting Tuesday as upper level ridging develops, though the Global Ensemble Forecast System is suggesting this may be less as an upper level trough approaches Pacific Northwest. Because of this, the NBM has trended a little less hot for Thursday, keeping highs in the 90s for the Valley. Highs could potentially reach triple digits over the northern Sacramento Valley on Friday, though confidence has lowered with increasing ensemble spread for the extent of the 4 Corners ridge.