March 4, 2020 – Dry through Thursday with well above normal daytime temperatures. Some record highs likely again today in the Central Valley. Chance of precipitation returns late Friday into the weekend.
Discussion
Mainly clear skies across the region early this morning. Surface pressure gradients have weakened compared to 24 hours ago, but enough north and east gradient remains for locally breezy conditions in the foothills and northern Sierra where gusts of 20-30 mph are still occurring. Current temperatures range from the lower to mid 20s in the mountain valleys to the upper 40s and 50s across the Central Valley.
Today will be another warm day as the broad upper ridge moves overhead. North winds will be lighter, so more uniform warm temperatures are expected through the Central Valley. More records will be in jeopardy.
Heights begin to fall Thursday as upper ridging shifts east into the Intermountain West while deep upper low from GOA digs SE towards the West Coast. Highs remain about 10 to 15 degrees above average Thursday, but are forecast below record values. Clouds begin to increase from the northwest Thursday night as associated Pacific frontal system approaches.
Front progged to push inland Friday night into Saturday bringing a chance of showers along with cooler temperatures as onshore flow and synoptic cooling take hold. Main theme is overall light precipitation is expected.
Extended Discussion (Sunday through Wednesday)
Other than a few possible isolated mountain showers, break in the precip expected Sunday under weak upper ridging. Closed upper low off the CA coast is forecast to gradually progress early next week. As with closed lows, models differ on how quickly precip will spread into the area from the SW. NBM leans towards the EC and raises POPs over the CWA Monday. GFS-20 is slower and keeps bulk of precip south of the forecast area through midweek. As a result, low confidence attm during latter part of the extended period.