Seasonal temperatures and a chance of light precip by mid-week

October 15, 2019 – Dry and mild weather early this week with temperatures close to average, then cooler for the second half of the week. A weather system will bring a chance of showers mid-week.

Discussion

Clear skies over NorCal early this morning. IR difference product still indicating some heat originating from the Caples wildfire near Kirkwood, but not as much as 24 hours ago. Easterly gradients are similar to early Monday, so some light smoke will be possible again this morning over the foothills and along the east side of the valley. Current temps range from the 20s in the mountain valleys to the mid 40s to mid 50s across the Central Valley.

Upper level ridging is over NorCal which will provide more dry and mild weather today and Wednesday before it moves to the east. Mostly sunny skies with highs near average for mid-October and chilly overnight lows are expected. Depending on fire activity, there will continue to be some areas of light smoke in the Central Valley in the mornings.

A stronger low pressure system approaches the West Coast mid-week that brings a chance of rain to NorCal Wednesday night through early Thursday. Ensembles are in better agreement with the latest GFS and ECMWF operational runs lending confidence to forecast of light precipitation to the mountains and northern Valley, mainly north of I-80.

Cooling temperatures behind the front for Thursday and Friday as the upper trough shifts east into the Rockies.

Extended Discussion (Saturday through Tuesday)

An upper level trough will be digging south into the region on Saturday along with a weak cold front. This will bring a chance for showers in the higher elevations with the best chances north. Shower chances will diminish Saturday evening as the trough pushes east and deepens in the Great Basin and Northern Plains, east of California. This pattern could bring somewhat breezy north winds Sunday. Currently winds are not expected to be very strong, generally 10 to 15 mph with gusts up to 20 to 25 mph over higher elevations. Upper level ridge builds in early next week.

Temperatures will start off below average but will be warming back to near to just above average as the ridge builds in early next week.