December 5, 2021
The fog is off the deck in most locations. A couple of examples are Bakersfield, where the ceiling is 200 feet with a visibility of one mile, Porterville is reporting one-mile visibility with drizzle falling, the ceiling is 300 feet at Visalia with ½ mile visibility, Lemoore is reporting a ceiling of 400 feet and 1.75 mile visibility, Fresno is 500 foot ceiling with a 2 mile visibility and Madera where the ceiling is 400 feet and the visibility is 4 miles.
Satellite imagery shows a classic fog regime with bright blue skies over the mountain and coastal sections and low clouds and fog filling the San Joaquin and Sacramento Valleys. Temperatures through Monday will be determined by afternoon clearing with readings in the 60s where it clears and upper 40s and lower 50s where the fog layer remains locked in.
Upper level high pressure stretches from a center off the central coast across California and into the Great Basin. The high will begin to give way Monday as a weak trough of low pressure moves through California. The question remains as to whether or not there will be enough lower level strength to scour out the valley of its low clouds and fog. For now, it appears the fog will lift and dissipate Monday afternoon with even a chance of sprinkles or isolated light showers Monday night and Tuesday morning. A brief ridge of high pressure will follow Tuesday night through Wednesday night for dry weather with patchy fog.
Models are continuing to show a much different weather pattern beginning Wednesday as a cold low drops out of the Gulf of Alaska and into California. This will be our best chance of a decent rain event since late October. Of interest also is the air mass associated with this system is cold. Upper 20s and lower 30s will be common possibly as early as Saturday morning and if not Saturday then Sunday. All the major players for frost will become apparent, such as fog and low clouds, upslope clouds, mixing parameters, and so on. It’s not a freeze event we’re anticipating, but it is a cold air mass moving in so frost appears likely.
Forecast: Low clouds and fog with local drizzle and a chance for afternoon clearing in some areas through Monday. The low clouds will clear Monday afternoon leading to a chance of sprinkles or isolated light showers late Monday night or early Tuesday morning. Partly cloudy Tuesday night through Wednesday. Increasing cloudiness Wednesday night with showers becoming likely Thursday and Thursday night. Mostly cloudy Friday. Mostly clear to occasionally partly cloudy Friday night through Sunday with areas of night and morning fog and low clouds.
Temperatures: Highs through Monday will range in the upper 40s and lower 50s where fog is persistent to the low to mid 60s where hazy sunshine breaks through. Highs Tuesday will generally be in the low to mid 60s. lows will range in the upper 30s to mid 40s tonight and Monday night with low to mid 40s prevalent Tuesday morning.
Next report: December 6