December 10, 2018
Summary: The low clouds and fog have cleared over the Sacramento Valley and down to near Stockton in the San Joaquin Valley. The remainder of the San Joaquin Valley, however, and the adjacent foothills are still locked in with a low overcast. The base of the overcast seems to be ranging at about 1,200 to 2,000 feet. The backside of a weak trough of low pressure will move through this evening. This will be a critical time to see if enough low level wind energy will mix out the fog and low clouds. Overnight low temperatures tonight will encompass a great deal of guess work on my part, but my feeling is low temperatures tonight will largely be similar to last night, ranging in the mid to upper 40s.
Temperatures as of 1:00pm were very uniform throughout the valley with all locations reporting upper 40s and lower 50s.
Another low will rapidly move through the Pacific Northwest Tuesday then dive into the Rocky Mountain region Wednesday, a bit further east than most models had projected. A high center will develop off the coast of southern California Thursday through Saturday, dragging the storm track back into the Pacific Northwest and northwest California. This will be Mother Nature’s next opportunity to sock the valley in with extensive low clouds and fog Thursday through Saturday.
Our next major change will occur Saturday night through Monday as a rather robust low pressure system moves into northern and central California. The main question with this system will be the southern progression of precipitation. Currently, it appears light precipitation may make it as far south as the Kern County mountains with the likelihood of rain from Fresno County north. Unfortunately for now, this appears to be a one storm event as models show a large high developing west of the California coast, driving the storm track northward into the Pacific Northwest. More fog and low clouds will no doubt develop after Monday and, if models hold, will be the issue for much of next week.
Forecast: Cloudy tonight and Tuesday morning. Partial clearing Tuesday afternoon and night. partly cloudy Wednesday with areas of morning low clouds and fog. Expect widespread low clouds and fog Thursday through Saturday with partial afternoon clearing. Increasing cloudiness Saturday night. rain becoming likely from Fresno County north Sunday through Monday with light showers likely in the south valley.
Short Term:
| Madera 43/53/37/55 | Reedley 44/53/37/54 | Dinuba 42/52/35/54 | |
| Porterville 42/55/36/55 | Lindsay 44/55/36/55 | Delano 46/54/39/55 | |
| Bakersfield 45/55/43/57 | Taft 44/55/40/55 | Arvin 44/54/40/56 | |
| Lamont 45/54/40/56 | Pixley 45/54/39/55 | Tulare 43/53/38/55 | |
| Woodlake 43/54/36/54 | Hanford 44/54/38/56 | Orosi 44/53/36/54 | |
Winds: Winds will be generally at or below 15 MPH through Thursday with periods of near calm conditions.
Rain: The next chance of rain will begin to increase late Saturday night with rain becoming likely Sunday through Monday. The main challenge with this storm will be the southern limit of rain. At this time, it appears the Kern County mountains will be the southern limit of the rain. Generally speaking, precipitation will be likely from Fresno county northward with light showers south of that line. Unfortunately, this appears to be a one storm event. Models are indicating high pressure will be building off the central and southern California coast, driving the storm track northward into the Pacific Northwest and northwest California. So, after Monday of next week we can expect dry weather.
Frost Discussion: All locations will be above 32 degrees tonight. The coverage of fog and low clouds will determine temperatures Wednesday through Saturday mornings and whether those temperatures drop into the low to mid 30s. the fog and low clouds have cleared throughout the Sacramento Valley down into the northern San Joaquin Valley. However, generally south of Stockton, generally overcast skies prevail and will likely continue through Tuesday morning. A brief north/northwest flow will follow the current trough moving through. It may or may not have enough low level wind energy to mix out the cloud deck. If the low clouds remain, low temperatures will continue to range in the 40s. If they do mix out, readings in the low to mid 30s would be widespread with even a small chance of upper 20s. I’m leaning towards the low clouds remaining in place.
High pressure will begin to take shape off the central and southern California coast Wednesday night through Saturday which will again favor the development of fog and low clouds. If this does happen, lows will remain in the 40s.
Once we get into Saturday night through Monday night, increasing clouds will prevail with an increasing chance of rain Saturday night through Monday for above freezing conditions.
High pressure will become reestablished next week for the likelihood of fog and low clouds again developing.
A couple of models really caught my eye this afternoon. Basically, it encompasses the 23 through the 27 of December. What they show is a ridge over the eastern Pacific jutting northeastward into the Yukon Territory of Northwest Canada and the development of a deep low possibly over southern California. This can turn out to be a freeze pattern as a strong northeasterly flow wraps around the high to our north then along the backside of the low over southern California. Historically, this pattern has produced widespread mid to upper 20s. Since this is the first day this pattern has shown up, we’ll take it with a grain of salt for now. However, if a trend develops in the coming days, we will begin to take matters more seriously.
Next report: Tuesday morning/December 11