Extended period of dry weather with sunny days and cool overnight temperatures this week. Possible pattern change this weekend into next week.
Discussion
Strong high pressure will remain over the region the next several days. A lighter northerly wind will occur during the day the next few days. Temperatures will be warming up into the mid 60s over the north end of the valley to the mid to upper 50s further south.
Continuing warming is expected for Wednesday when most valley temperatures will be around 60 degrees and winds look to be slightly stronger due to a weak wave dropping down through the Great Basin. Just a few patches of frost and fog are expected the next couple of mornings mainly over the central part of the Northern San Joaquin valley today then maybe some a little further north to around Sacramento. Otherwise fair weather is expected.
Little change is expected for Thursday other than lighter winds. Foothills should be warming up nicely this week with many highs in the upper 50s to lower 60s.
Friday the ridge will begin to break down as a weak wave drops down from the north over Oregon. Temperatures will be slightly cooler and winds are expected to shift direction. This may allow for more fog to develop in the central part of the valley for Friday morning.
Extended Discussion (Saturday through Tuesday)
Latest ensemble guidance indicates a trough will dig southward over the western United States this weekend and into next week, as well as the flattening the ridge over the eastern Pacific.
Depending on where this trough sets up will determine if interior northern California could potentially see some light precipitation, or remain mostly dry with locally breezy north to east winds, however there is still some divergence in the models and uncertainty in the cluster analysis for timing and location.
Either way, a troughing pattern looks to return to the region over the extended forecast period. Confidence is higher for cooler temperatures to accompany this trough, as the Extreme Forecast Index (EFI) highlights below normal daytime high and overnight low temperatures for early next week.