November 12, 2019 – Dry weather pattern continues this week. Cooling trend this week, but above normal high temperatures continue. Warmer this weekend.
Discussion
Partly cloudy skies (high clouds) cover the region early this morning. Northerly surface pressure gradients have dropped off considerably compared to 24 hours ago (KMFR-KRDD currently around 1.5 mbs compared to over 6.5 mbs at this time Monday) while the easterly gradient KRNO-KSAC is still around 5 mbs. Local northeast wind gusts of 15-30 mph linger across the foothills and west slopes of the northern Sierra. Current temperatures range from the upper 20s in the mountain valleys to the upper 50s to lower 60s across the warmer foothill and mountain thermal belts.
Strong ridging will gradually shift east later Wednesday into Thursday as the closed low, presently near 30N/145W, weakens and approaches the West Coast. The system will bring some cooling along with mostly cloudy skies as it moves through Thursday into Friday. High temperatures will remain above average.
Extended Discussion (Saturday through Tuesday)
Upper level ridging will be in place for the start of the extended period. This will result in a warming trend along with a decrease in humidity. High temperatures will be around 5-15 degrees above average for mid-November.
Upper level ridge flattens early next week as a trough digs into the PacNW. Deterministic models keep the trough a bit further to the west and pull in some moisture Tuesday/Wednesday but ensembles are drier and further to the east with it. We will likely see models shift to this scenario and have kept the forecast dry. If ensembles are correct with the placement of the trough we could see breezy north winds Tuesday continuing into Wednesday with low relative humidity.