November 18, 2019 – Warm and dry again today with record highs possible. Pattern change still on track beginning Tuesday with breezy to windy conditions, cooler temperatures and possible showers over mainly the Sierra Nevada. Fire Weather Watch from late Tuesday night through Thursday morning for Central Sacramento Valley in Glenn, Colusa, Yuba, Northern Sutter, and Butte County Below 1000 Ft.
Discussion
Clear skies cover the area early this morning as the strong ridge has lifted high clouds north of the region. Current temperatures are about the same as 24 hours ago across most of interior NorCal and range from the mid 20s in the mountain valleys to the mid 40s to lower 50s across the Central Valley. Milder foothill and mountain thermal belts are currently in the lower to mid 60s.
High pressure will hold out for one more day of dry weather with warm temperatures. Forecast highs today in the mid to upper 70s will approach daily records for much of the Central Valley.
The system presently along 140W, north of 45N, will continue to move east-southeastward toward the PacNW over the next 24 hours. Latest ops runs match pretty well with the ensemble mean indicating that it will split with the southern portion digging into NorCal by Tuesday afternoon before closing off near Monterey Bay late Tuesday night, and then into SoCal on Wednesday.
Temperatures cool off with this mid-week system, although highs still stay about 4-8 degrees above average for mid-November in the valley. The main focus of this system will be the return of showers to the northern Sierra later Tuesday into Wednesday along with breezy north winds.
Northerly breezes pick up later Tuesday, with the strongest winds expected in the Sacramento Valley and surrounding terrain on Wednesday into Wednesday evening. Peak gusts around 35-45 mph may be seen in the Valley.
Shower chances begin later Tuesday and continue into Wednesday night, mainly over the Sierra. Snow levels look to be around 4500-5500 ft with a few inches of accumulation possible at the higher elevations.
Extended Discussion (Friday through Monday)
High pressure extends back into northern California Friday with mild temperatures, light winds, and dry weather expected. Afternoon highs will continue to trend slightly above normal for late November from Friday through early next week. Ensemble guidance suggests a trough may move across the area early next week; however, have continued dry conditions on Monday. Another period of breezy north winds may be possible with this potential system.