November 24, 2017
Summary: Visibilities this afternoon are not all that bad, considering the time of year, with most locations reporting a visibility of between 4 and 7 miles. As of the time of this writing, most locations were moving into the lower 70s with many locations, by the time the day is over, no doubt topping out into the mid 70s.
The big high that has resulted in the prolonged period of dry, warm weather will slowly break down over the weekend. Currently, it’s centered over northwest Mexico and extends northward into northern California. Over the Pacific Ocean is a wide swath of cloud cover stretching from east of Hawaii up to the Pacific Northwest and northern California. The bulk of this moisture will move into Washington and Oregon.
A trough of low pressure is now dropping southeastward out of the Gulf of Alaska. It will spread precipitation over northern California as early as Saturday evening. Some models are showing a secondary low forming right along the trough which will move through central California from late Sunday afternoon through Monday morning. Since this low seems to be aimed right at central California, the chance of rain has increased as the main dynamics of this storm will dig further south than previously projected. In fact, it appears precip will reach all the way into Kern County. Fresno County could receive some shower activity as early as midday Sunday or so as subtropical moisture spreads in ahead of the trough. This will be a fast mover, so no heavy amounts are expected at this time.
Upsloping will occur Monday night and Tuesday with only slow clearing in the south valley and possibly along the east side. By the time we get into Wednesday and Thursday, the pattern becomes more complex as a new trough moves through about Wednesday morning then possibly forms a new low over southern Nevada by Thursday. This would turn the winds at the surface and aloft off shore which potentially could pump some colder air down the valley. I’m not ready to call for a frost night yet, but if this pattern does happen to come to fruition, the chance for some frost nights would certainly increase.
Also, the pattern for a week from Sunday and Monday of next week looks rather odd on paper. It shows a very large upper low pinching off from a trough of low pressure moving southward then parking off the central coast for a few days. This potentially could mean a number of different things: anything from periods of rain to a possible northeast flow for a potential northeast flow which, again, could pump some cold air into the valley. At this point, we’ll just have to watch and see how things behave. One thing is for sure, though. The mundane pattern of late is coming to a screeching halt.
Forecast: Mostly clear to occasionally partly cloudy tonight. Partly cloudy Saturday. Increasing cloudiness late Saturday night. rain spreading down to Fresno by roughly midday Sunday with showers spreading over the south valley over the afternoon and evening. Showers Monday morning then becoming mostly to partly cloudy Monday afternoon through Tuesday morning. Mostly clear to occasionally partly cloudy Wednesday and Thursday with areas of morning fog. Mostly clear with areas of morning fog Thursday night and Friday.
Short Term:
Madera 46/73/49/74 | Reedley 47/74/50/75 | Dinuba 46/74/49/75 | |
Porterville 46/75/48/75 | Lindsay 45/75/48/77 | Delano 48/76/51/77 | |
Bakersfield 53/77/56/79 | Arvin 48/78/53/80 | Taft 55/79/56/79 | |
Lamont 49/79/53/80 | Pixley 46/76/50/77 | Tulare 45/75/48/76 | |
Woodlake 46/75/49/76 | Hanford 46/75/50/76 | Orosi 46/74/49/75 |
Winds: Winds will be generally less than 10 MPH through Saturday night with periods of near calm conditions. Winds Sunday will be out of the southeast at 5 to 15 MPH with local gusts to 25 MPH Sunday afternoon and Sunday night. Winds Monday will switch and become out of the northwest at 10 to 20 MPH with stronger gusts, diminishing Monday evening.
Rain: The chance of rain is greatly increased now, according to the latest forecast models as a trough of low pressure digs through the Pacific Northwest and northern California. This may form a secondary low right along the portion of the front which will move through central California Sunday night and early Monday. If this is the case, precipitation will spread all the way down the valley, including Kern County, with decent amounts than we were first considering. The chance of rain may reach Fresno County as early as Sunday then spread down the valley with showers Sunday night and Monday morning. This will be a fast mover, so dry weather will return Monday afternoon.
The pattern for the middle of next week appears dry at this time, but that’s a low confidence forecast as models are showing a possible low anywhere from off shore southern California to southern Nevada. There’s also some indication of the possibility of rain about the third or fourth of December. This will depend on the placement of a large low.
As far as precipitation amounts go for Sunday night through Monday morning, it looks like a quarter of an inch or so from Fresno County northward with lesser amounts further south.
Frost Information: All locations will be above 32 degrees through Monday morning. The air mass flowing in behind the Sunday night/Monday event is colder and will finally make it feel like late November. Lows for Tuesday and Wednesday of next week may largely be determined by cloud cover left crammed into the valley. Where it clears, mid to upper 30s are certainly possible with lower 30s not out of the question. The configuration for Thursday and Friday of next week is also becoming more interesting with time. There is some suggestion of a low developing over southern Nevada about Thursday which would result in an off shore flow both at the surface and aloft, potentially pumping colder air southwestward from the northern Rockies. I’m not ready to forecast frost nights as of yet since this is the first time this pattern has shown up, but it will be something to keep a close eye on as we move through the weekend and into next week.
Next Report: Saturday morning, November 25