May 14, 2020 – Precipitation chances and cooler temperatures continue today. Warmer and drier weather briefly returns Friday into Saturday followed by wet and cooler weather early next week.
Discussion
Mostly cloudy skies along with a few showers continue across the region early this morning. Current temperatures are running similar to readings 24 hours ago and range from the mid 30s to lower 40s in the mountains, to the 50s across the Central Valley.
Upper low will continue to spin off the PacNW coast today maintaining a weak trough across NorCal. A couple more short- waves will move across the area, the first this morning followed by another this evening, maintaining shower chances north of I-80. Temperatures will be around 5-15 degrees below average.
Mid/upper ridging returns Friday into Saturday resulting in a brief warmup along with two days of dry weather. Highs across the Central Valley will return to the mid 70s to mid 80s (close to average for mid-May).
Anomalously cool and wet weather system then forecast to affect the region late in the weekend into early next week. GEFS and EC ensembles still point toward significant QPF across the northern mountains, northern Sacramento Valley, and northern Sierra Nevada as frontal system moves slowly southeast across the region.
Extended Discussion (Monday through Thursday)
A deep upper low located off the coast of NorCal will bring additional precipitation to the area on Monday. In the Valley, showers and some isolated thunderstorms will be possible as this feature moves inland, with the best chances for storms in the northern Sacramento Valley where instability looks greatest. Snow levels fall a bit Monday between 6-7kft, with some light accumulations at pass level possible. Most precipitation looks to shift towards the mountains and foothills on Tuesday, although some activity in the Valley is not out of the question. By mid-week, lingering mountain precipitation may still be seen as the upper low moves into the Northern Plains, with dry weather elsewhere. Below average highs thru mid-week rise to near normal by Thursday.