June 29, 2017 – Slightly warmer temperatures today with warm conditions through the weekend. Slightly cooler next week but remaining a little warmer than normal. No mountain thunderstorms expected through the extended period.
Discussion
Fair skies over the CWA this morning under high amplitude upper level ridge over the eastern Pacific. Still have a fairly healthy delta breeze blowing this morning with a moderate marine layer hanging in at around 1600 feet. Some coastal stratus moving into the Bay area and may see some patchy stratus this morning western Solano county.
Airmass warms a bit today as upper ridge axis centers over the area so expecting high temperatures today a few degrees over yesterday. Subsidence and stability over the region under the ridge will keep any mountain thunderstorm threat out of the forecast over the next several days. Upper ridge axis crosses over the north state Friday bringing more warming with daytime highs expected to reach up to about 10 degrees above normal.
A moderate delta breeze is expected to continue but high pressure ridging will keep the marine layer and stratus intrusion into the delta minimal. A weak upper trough passing through the Pacific Northwest on Saturday will have minimal impact on CWA weather with its main impact to keep daytime highs Saturday from climbing. Upper ridging moves quickly back over the west coast bringing a slight warming again on Sunday.
Extended discussion (Monday through Thursday)
High pressure aloft will create warm and dry conditions across northern California with temperatures near normal. A trough pattern could develop for the middle of next week, but model forecasts are still a bit uncertain and lack agreement.
If a trough does develop, temperatures could drop a few degrees but will still remain near normal. Best lift dynamics appear to remain well north of the forecast area, so any development for precipitation looks very limited at the moment. However, a mountain shower or thunderstorm cannot be ruled out Wednesday or Thursday of next week.