December 21, 2017
Summary: Temperatures are 1 to 5 degrees colder this afternoon than 24 hours ago. Dew points are down 5 to 12 degrees. A cold pool of dry air has now settled to the bottom of the bathtub, setting the stage for a strong radiational cooling event tonight. Low to mid 20s appear likely in most locations with hillsides faring a little better, perhaps sneaking into the upper 20s to the lower 30s. that cold low which was responsible for the modified Arctic air moving down the valley is already near the Utah/Colorado border. In the meantime, high pressure off shore is beginning to move inland which will start the process of a warm air inversion over the valley floor, especially for this weekend. More on all this is discussed in the frost section below.
A series of cold nights will continue through at least Christmas morning. Even though the winds aloft will be out of the west starting Friday night, a layer of dry air will again be trapped on the valley floor.
Medium range models are somewhat inconclusive at this time. However, all point to dry weather. the only question in my mind is whether another burst of modified Arctic air will move into the valley about the 28th. Models are less bullish on this this afternoon, but as we know, the typical flip flop may apply here.
Forecast: Mostly clear tonight through Friday. Mostly clear Friday night through Christmas Day with occasional periods of high and mid level clouds. Mostly clear to occasionally partly cloudy Monday night through Thursday.
Short Term:
| Madera 25/56/25/58 | Reedley 23/56/24/58 | Dinuba 22/56/24/58 | |
| Porterville 25/57/25/59 | Lindsay 23/56/24/59 | Delano 25/57/26/60 | |
| Bakersfield 28/58/31/60 | Arvin 24/57/26/59 | Taft 29/57/30/61 | |
| Lamont 24/57/26/60 | Pixley 23/56/25/59 | Tulare 22/56/24/58 | |
| Woodlake 23/56/25/58 | Hanford 23/57/26/60 | Orosi 24/56/25/59 | |
Winds: Winds will be generally less than 10 MPH through Sunday with periods of near calm conditions.
Rain: Expect dry conditions for at least the next seven to ten days.
Frost Information: Temperatures this afternoon are running 1 to 5 degrees colder despite all the sunshine this afternoon. Dew points are down anywhere from 5 to 12 degrees and are generally in the upper 20s to the mid 30s. North of Merced, dew points are in the low to mid 20s, but for now I’m not anticipating that dry air just to our north to infiltrate our region.
With the cold air in place and slowly becoming capped by upper level high pressure, we have an inversion forming. Strong radiational cooling will occur tonight under generally clear skies. Widespread low to mid 20s appear likely with hillsides generally ranging from 29 to 33.
Coldest locations in unprotected areas will hit the freezing mark by 9:00pm and 28 degrees about midnight or shortly thereafter. The very coldest areas could drop to 21 or 22 with the more typical flat terrain situations ranging from 23 to 26.
The inversion tonight will be a bit better with temperatures at 34 feet ranging from generally 3 to 5 degrees warmer at most locations.
Looking ahead to Saturday morning, at least mid 20s are expected although projections are now showing occasional periods of clouds being caught up in a developing flow aloft. For now, I’m not counting on these potential clouds, nor can I anticipate they’ll do much good, but they may help out some on Christmas Eve and Christmas Day mornings. Just the fact that a westerly flow will develop this weekend will give me a little solace.
Medium range outlooks do call for very slow modification especially during the day with temperatures moving into the low to mid 60s over this weekend. This should drag up overnight lows after Christmas. However, models are still inconclusive about another potential shot of modified Arctic air moving into the valley about the 28. Most models this afternoon are, admittedly, keeping this air to the east, but we’ll keep a close eye on it considering the trends of the month.
Lows Tonight:
| Terra Bella
23 |
Porterville
25 |
Ivanhoe
24 |
Woodlake
24 |
| Strathmore
25 |
McFarland
23 |
Ducor
25 |
Tea Pot Dome
24 |
| Lindsay
23 |
Exeter
23 |
Famoso
26 |
Madera
25 |
| Belridge
24 |
Delano
26 |
North Bakersfield
25 |
Orosi
23 |
| Orange Cove
24 |
Lindcove
23 |
Lindcove hillside
29 |
Sanger River Bottom
20 |
| Root Creek
23 |
Venice Hill
25 |
Rosedale
25 |
Jasmine
24 |
| Arvin
25 |
Lamont
25 |
Plainview
24 |
Mettler
27 |
| Edison
25 |
Maricopa
25 |
Holland Creek
29 |
Tivy Valley
25 |
| Kite Road South
28 |
Kite Road North
25 |
Next Report: Friday morning, December 22