September 28, 2019
Summary: As of 1:00pm, temperatures were huddled in the mid 70s throughout the valley. Most locations were seeing sunshine with most of the cloud cover banking up against the west facing slopes of the Sierra Nevada and the adjacent foothills. Temperatures were 5 to 7 degrees lower than yesterday at this time. It’s hard to believe, as we are still in September, but where skies remain clear and clouds die off, typical low spots will dip into the upper 30s with widespread low to mid 40s elsewhere.
A secondary cold front extends from Idaho southwestward through the lower Sacramento Valley then out to sea. This will issue in another shot of unusually chilly air for this early in the season. Yet a third impulse is entering extreme northern California, continuing the unusually cool early November-type weather.
It appears any chance of precipitation is over as drier air has moved in both at the surface and aloft, although scattered light showers and higher elevation snow showers will continue tonight and Sunday over the higher elevations of the Sierra Nevada.
The center of low pressure is sagging southward into eastern Oregon now with a strong trough running through California. This system will remain pretty much in place through Monday night then will finally shift eastward Tuesday, allowing for marginal warming. By Wednesday, a flat zone of upper level high pressure will move into central California from the eastern Pacific. By Thursday, temperatures will actually return closer to normal, even though a weak trough of low pressure will be passing inland through the Pacific Northwest and extreme northern California.
Nothing exciting shows up on medium range models with generally a westerly flow in the upper atmosphere. No major storm systems or upper level high pressure is expected to dominate the pattern. No excessively warm weather will occur and no precipitation for the next week to ten days.
Forecast: Mostly clear to occasionally partly cloudy through Sunday evening. Mostly clear Sunday night through Wednesday with a slow warming trend. Mostly clear skies will continue Wednesday night through Saturday.
Temperatures: Lows tonight will chill into the low to mid 40s except upper 40s and lower 50s in Kern County. Highs Sunday and Monday will only top out in the upper 60s to the lower 70s. lows Sunday night will again chill into the low to mid 40s with upper 30s possible in river bottom and like locations.
Next report: Monday, September 30