April 7, 2017 – A strong spring storm will bring gusty winds, showers, a few thunderstorms and heavy mountain snow through Saturday. Showers are forecast to taper off by Sunday.
Strong late-season storm continues to affect the region early this morning. Satellite imagery shows the center wrapping up off the PacNW coast while the main frontal band has shifted south into central California. Temperatures are colder compared to 24 hours ago and range from the 30s in the mountains to the 40s and lower 50s elsewhere.
Winds have decreased compared to earlier in the night, but gusts of 30-40 mph continue across the northern half of the Sacramento Valley and over the mountains.
The Sacramento-Medford gradient remains around 14-15 mbs while the Fresno-Sacramento gradient has dropped from 6 mbs at midnight to its current reading around 3 mbs.
Winds will taper off further this afternoon, but may pick up again this evening as the next wave moves onshore.
Precipitation will be showery across NorCal today with perhaps a few thunderstorms this afternoon. The next wave is taking shape around 35N/135W and will move into NorCal tonight bringing another shot of heavier precipitation including more heavy snow over the mountains.
Precipitation will taper off early Sunday with a break expected before the next system brings a chance of showers Sunday night.
Extended discussion (Tuesday through Friday)
Most locations will see dry conditions on Tuesday under flat upper level ridging. GFS and ECMWF both pass a small shortwave through the Pacific northwest however so areas north of about Red Bluff will see a slight threat of light showers Tuesday afternoon.
Cold upper low dropping into the eastern Pacific will bring next round of Winter-like weather to northern California on Wednesday. Warm sector precipitation should start spreading over Norcal by Wednesday afternoon although model timing varies a bit. Precipitation starts out light on Wednesday so impacts will be fairly minimal under moderate snow level conditions.
Frontal passage times out sometime next Thursday. This system will bring another round of rain, mountain snow and gusty winds. Snow levels will again be below pass levels over the Sierra so travel impacts would be likely under the current scenario. Showers continue into Friday as the upper low pushes on to the west coast.