September 26, 2016 – Dry weather continues. Above average temperatures through Tuesday, then cooling trend begins Wednesday.
Clear skies early this morning with strong ridging along the West Coast. Offshore flow continues with many spots in the Sierra foothills seeing easterly winds gusting 15-30 mph. Temperatures are mostly on the mild side ranging from the upper 30s in the mountain valleys to the 60s through the Central Valley. Many foothill locales are in the 70s to around 80.
Offshore flow will weaken by this afternoon, but it will be another hot day across interior NorCal with triple digits possible through the Central Valley. The North Valley may shed a few degrees compared to Sunday as north winds slacken in the afternoon. Readings on Tuesday are expected to be very similar to today.
The ridge shifts east Wednesday and Thursday as another trough develops off the coast of the PacNW. Temperatures will return to average for late-September as onshore flow increases.
Extended discussion (Friday through Monday)
A cool upper level trough from the Gulf of Alaska will bring much cooler temperatures next weekend and a slight chance of precipitation over the northern mountains.
Friday highs are expected to be 5 to 10 degrees below normal, generally around 80 in the Valley. The weekend looks even cooler as the trough moves on-shore. Waves embedded within the trough will bring the potential for some showers over the northern mountains. Moisture with this cool system is quite limited so not expecting to see significant precipitation at this point.
The main effects of the trough are expected to be much cooler temperatures, especially compared to this past weekend. Valley highs are expected to be limited to the 70s. There could also be some breezy winds in the mountains.