December 21, 2020
Summary: Upper level high pressure is weakening ahead of a fast moving trough of low pressure moving into the Pacific Northwest. Hazy sunshine is dominant from roughly Visalia southward in the south valley. Porterville has warmed up to 58 degrees as has Bakersfield. It is downright cold from central Tulare County northward to the lower Sacramento Valley. Madera, Lemoore, and Hanford were only reporting 42 degrees with a visibility of just ¼ mile as of 1:30pm while Visalia was clearing out but still reporting just 44 degrees.
Where skies have cleared this afternoon, widespread ground fog will form as the night progresses. Last night, right along the edge of the fog bank, readings dropped into the mid to upper 20s and we’ll have to watch for the same type of weather behavior tonight.
That low moving inland to our north will turn into a strong winter storm over the northern Rockies Tuesday followed closely by a sharp ridge of high pressure along the Pacific coast which will build northward into Alaska. The combination of the exiting winter storm and the incoming high will generate a northwest flow over California, keeping any arctic air well to our east.
By Wednesday afternoon, a weak upper low will be approaching the central and southern California coast. No active weather is anticipated with this system, but we should see some increase in mid and high level clouds and it may break up the inversion enough to shorten the time frame of the fog and low clouds.
On Christmas Day, clouds will begin to increase ahead of a trough of low pressure which will move through northern and central California late Friday night and Saturday. the trend that began on yesterday’s models of the rain line being nudged north continues this afternoon. It’s possible the south valley may nor receive any precipitation at all and even from Fresno north, it appears just light showers are possible…possible, but not guaranteed.
For now, it appears we’ll have a better shot at precipitation Sunday night and Monday. For now, a low shows up west of San Francisco by early Monday morning then moving south/southeast over central and southern California later Monday and Monday night.
Forecast: From Visalia south it will be mostly clear this evening, but with widespread dense fog developing later tonight. north of Visalia, expect areas of low clouds and dense fog. Widespread fog and/or overcast Tuesday afternoon through Wednesday night with partial afternoon clearing, especially along the foothills and in Kern County. Extensive fog and low clouds Christmas Eve morning, becoming partly cloudy in the afternoon. Variable cloudiness at times Thursday night and Christmas Day with areas of night and morning fog and low clouds. Mostly cloudy Friday night with a slight chance of showers from Fresno north. A chance of showers Saturday, mainly from Fresno County north. Mostly cloudy Saturday night and Sunday. A chance of showers Sunday night with a higher possibility of showers Monday.
Short Term:
| Madera 31/48/34/48 | Reedley 30/49/32/48 | Dinuba 31/47/34/47 | |
| Porterville 28/58/29/58 | Lindsay 27/54/28/56 | Delano 29/50/31/57 | |
| Bakersfield 35/59/36/60 | Taft 45/60/46/62 | Arvin 33/58/34/60 | |
| Lamont 32/58/34/59 | Pixley 29/53/32/51 | Tulare 31/47/34/47 | |
| Woodlake 28/51/29/50 | Hanford 30/48/32/48 | Orosi 27/53/29/51 | |
Winds: Winds through Christmas Eve will be generally less than 10 MPH late mornings and afternoons and at or less than 5 MPH during the night and early morning hours with extended periods of near calm conditions.
Rain: Dry weather will continue through Christmas Day. Some light drizzle during the late night and morning hours will be possible in some areas. Late Friday night and Saturday, a weak trough of low pressure will move through. Models yesterday began showing the rain line moving farther north and that trend shows up even more so today. It’s possible now the south valley will remain high and dry and even from Fresno County north, it’s advisable to pull things back a bit and just call for a chance of light showers. Our best chance at rain for the next week to possibly ten days will be Sunday night and Monday of next week. Models show a low just off the coast of San Francisco Monday morning, tracking southward through central and southern California Monday night into Tuesday. For now, after Tuesday there is no real signature for precipitation for the next several days.
Frost: Skies have cleared as of 1:30 this afternoon over the southern half of Tulare County through all of Kern County. North of roughly Hanford, the fog has completely taken over with temperatures only in the low to mid 40s. widespread dense fog will reform where it has cleared this afternoon. We have the same challenge tonight we had last night for those areas just outside the fog bank. As the fog creeps in towards the foothills, temperatures can sometime shoot down a few degrees in a short period of time. Laslt night, that caused several locations to rocket down into the mid to upper 20s.
The coldest areas tonight will be near the bse of the Sierra Nevada in Fresno County but more so in Tulare County. If the fog moves in early enough tonight, readings will be a tad milder than forecast. At any rate, the coldest frost pockets out of the fog could drop as low as 25 to 26 degrees with most flatland areas north of Kern County ranging from 27 to 31 with low to mid 30s again in Kern County.
Expect temperatures at 34 feet tonight to range between 4 and 8 degrees warmer than at ground level at most locations.
We will have to watch the burn off time of the fog Tuesday and Wednesday afternoons and formulate a plan for those nights. I keep hoping the fog lifts into a low overcast but so far it refuses to do so.
We should begin to see some higher clouds Christmas Eve and Christmas Day which, theoretically, would help somewhat.
Look for above freezing temperatures Saturday through Monday as higher clouds take over for a change.
Lows Tonight:
| Terra Bella
28 |
Porterville
27 |
Ivanhoe
26 |
Woodlake
28 |
| Strathmore
27 |
Mcfarland
27 |
Ducor
28 |
Tea Pot Dome
27 |
| Lindsay
27 |
Exeter
27 |
Famoso
28 |
Madera
31 |
| Belridge
27 |
Delano
28 |
North Bakersfield
29 |
Orosi
28 |
| Orange Cove
28 |
Lindcove
27 |
Lindcove Hillside
Af |
Sanger River Bottom
26 |
| Root Creek
28 |
Venice Hill
28 |
Rosedale
28 |
Jasmine
29 |
| Arvin
32 |
Lamont
32 |
Plainview
27 |
Mettler
33 |
| Edison
33 |
Maricopa
28 |
Holland Creek
30 |
Tivy Valley
27 |
| Kite Road South
30 |
Kite Road North
27 |
AF=Above Freezing
Next update: December 22/am