July 6, 2018 – Near to a little below normal temperatures today with clouds. Slow warming to a little above normal by Monday. Smoke near wildfires and hazy conditions at times elsewhere. A slight chance of Sierra showers middle to end of next week.
Northern California under stable southwest flow aloft between a high pressure ridge over the southern U.S and a low pressure system off the coast. The southwest flow has pulled mid to upper level moisture from tropical storm Fabio northeastward over NorCal so should see a fair amount of cloudiness over the forecast area today especially during the morning hours.
So far no precipitation has been observed but can not rule out a stray light sprinkle at some point today. Overall airmass is similar to Thursday as well as the delta breeze and cloud cover should not be particularly thick Therefore should see daytime highs today similar to Thursday.
Offshore trough shifts northeast into the Pacific northwest tonight allowing southern U.S high pressure ridge to push back westward. This will cause daytime highs Saturday to pump upward to a few to several degrees above normal.
Fair skies and warm temperatures continue into Sunday under high pressure ridging. Upper ridge amplifies over the west a bit more Monday as a Pacific trough approaches the coast. This will bring just a bit more warming Monday with these warmer than normal temperatures expected to continue going into next week.
Extended discussion (Tuesday through Friday)
Upper ridging will continue to dominate the weather pattern across interior NorCal through the extended forecast. Not much change in terms of daytime highs is expected through the forecast period, with most Valley locations remaining in the 90s and 70s to 90s over the foothills/mountains. The exception will be the northern Sacramento Valley, with highs expected to exceed the century mark. These high temperatures will be a few degrees warmer than normal for this time of the year.
Guidance continues to indicate a surge of monsoonal moisture that might result in afternoon convection over higher terrain around the middle of next week into late next week. Dry conditions expected elsewhere.