February 26, 2020 – Dry weather with above average temperatures and locally breezy northerly winds at times this week. Cooling temperatures along with scattered mountain showers possible over the weekend.
Discussion
Except for a few high clouds passing through, skies remain clear across the region early this morning. North and east surface pressure gradients have relaxed considerably compared to 24 hours ago, but enough gradient lingers (MFR-RDD is 5 mbs, and RNO-SAC is around 4.5 mbs) for locally breezy north/northeast winds across the foothills of the northern Sacramento Valley where a few gusts in the teens and 20s mph remain. Gusts in the mid 20s to lower 30s mph still present near the mouth of the Feather River Canyon.
Current temperatures range from the lower 20s in the mountain valleys to the 40s to lower 50s across the Central Valley. Foothill thermal belts are in the mid 50s to lower 60s.
Strong ridging will continue the dry and mild weather pattern through Friday. Highs will be well above average (10-20 degrees) with a few daily records possible.
Pattern change develops over the weekend as the ridge is displaced eastward by a deepening trough over the eastern Pacific. Temperatures are forecast to cool about 10 degrees from Friday to Saturday and scattered showers will be possible over mainly the foothills and mountains.
Extended Discussion (Sunday through Wednesday)
Upper low digs through CA Sunday bringing cooler temperatures and gusty wind. Best chances for measurable precipitation look to be over the eastern foothills and mountains. Overall QPF looks light with snow levels lower to 2000 to 3000 feet. Precip chances diminish Sunday night as the trough digs south of the CWA. Breezy north to east wind develops Sunday night into Monday and persists into Tuesday, as EPAC high builds inland. AMS warms Monday under increased subsidence and downslope flow. Model differences increase further into the extended. Main theme is EPAC high remains dominant synoptic features with weak waves moving through it giving a slight chance of showers over the Shasta mountains Tuesday into Wednesday.