September 21, 2020 – Chance of showers over the Shasta and Coastal mountains Wednesday night and Thursday, otherwise dry weather expected. Temperatures close to average this week, then hot weather returns over the weekend.
Discussion
Clear skies cover the region early this morning. North to northeast surface pressure gradients have weakened compared to 24 hours ago, but a few gusts in the teens mph are still occurring across the northern Sacramento Valley and surrounding foothills. Current temperatures are running a little milder compared to 24 hours ago across most of the Central Valley despite the Delta Breeze beginning to trend higher.
Widespread moderate to unhealthy AQI currently covers the area, but smoke and haze is forecast to move to the north and east later today and tonight as the upstream short-wave trough approaches inducing stronger southwesterly flow. Otherwise, mostly dry weather with near average temperatures are expected through much of the week.
The exception will be a weakening cold front that is forecast to wash out across far northern California Wednesday night and Thursday bringing some light precipitation to the northern Coast Range and southern Cascade Range. Locally breezy southerly winds expected in the afternoons Tuesday thru Thursday.
Extended Discussion (Friday through Monday)
Frontal system moves through the PacNW Friday with associated precipitation remaining north of the CWA. EPAC upper high then builds into NorCal Saturday into Monday resulting in a warming trend with above normal temperatures. Latest guidance pushes high temperatures in the Central Valley into the upper 90s by Monday with mostly 80s to low 90s for the mountains and foothills.