May 27, 2019 – Mainly late-day mountain showers and thunderstorms continue thru the week. Temperatures return to average by mid-week.
Discussion
Satellite imagery indicates the cold closed low now centered over southern Nevada with NorCal seeing backwash from the north and northeast. Radar indicates a few light showers continuing early this morning. Current temperatures range from the 30s in the mountains to the 50s across the Central Valley.
Lingering showers are expected to taper off by late this morning. Scattered showers and a few thunderstorms will then redevelop over mainly the higher terrain this afternoon, though a few could drift down into the northern Sacramento Valley and foothills.
A relative minimum of activity is forecast for Tuesday as short- wave ridging temporarily moves overhead, but weak cyclonic flow returns Wednesday and Thursday resulting in an increase in late- day showers and thunderstorms over the mountains.
Temperatures warm slightly today, with more significant warming returning Tuesday. Highs are forecast to return to average by Wednesday.
Extended Discussion (Friday through Monday)
The period spanning Friday into early next week will favor rising temperatures along with near daily chances for mountain thunderstorms. Initially, the synoptic configuration features a broad upper low over the central Great Basin which gradually sags southward toward southern California.
Embedded shortwaves combined with diurnal heating support daily occurrences of mountain showers and thunderstorms, particularly through the weekend.
Looking to next week, the eastern extent of an offshore upper ridge will skirt the region. The building heights support the continued warming trend with perhaps the first 100 degree reading for Redding as noted in some of the guidance.
After a cool May, it appears June will start off quite warm, but also closer to climatology.