May 24, 2021 – A few showers are possible this afternoon over the Shasta County Mountains, otherwise dry. Temperatures will be near or above average through the week.
Discussion
Short term ensembles in good agreement with progressive pattern in place, as upper lows continue to track across the Pacific Northwest with jet stream situated near the Oregon/California boarder. Temperatures will be near to slightly above normal through Thursday with heights still slightly on the higher side despite weak troughing passing through the area. Slightly cooler temperatures in Delta influenced areas where weak onshore flow persists.
Weak disturbance passing through extreme Northern California may produce a few showers and thunderstorms over the Coast Range, Southern Cascades and Shasta county this afternoon.
Short wave ridge briefly strengthens Wednesday before next disturbance drops through in progressive pattern. Winds will be generally less than 10 mph through the week, except in typical breezy Delta locations.
Extended discussion (Friday through Monday)
Model differences through the extended period lead to some forecast uncertainty. Models suggest upper trough or low moving into CA over the weekend but differ with strength and track. For now progs suggest potential for some afternoon deep moist convection over the Sierra Nevada Saturday and Sunday. Some minor synoptic cooling expected over the weekend but high temperatures remain above normal. Ensemble solutions support EPAC upper ridging building back inland early next week.