December 15, 2017
Summary: For the next several hours, upper level high pressure off the southern California coast will be the dominant player. That will change late tonight and early Saturday morning as a dry trough and associated cold front move quickly down the valley. Already this afternoon, high clouds have spread as far south as northern Kern County and will thicken up later tonight as the cold front approaches. The trough will cause pressure over Nevada to lower and eventually Arizona, creating some gusty winds tomorrow, mainly along the west side of the valley along the Interstate 5 corridor. Winds could surpass 30 MPH. Upper level high pressure will quickly bounce back and build northward Sunday through Tuesday, creating a dry north/northeast flow aloft. This will inject somewhat colder and dry air onto the valley floor, switching us back to mid to upper 20s in many areas with a good number of locations in the low to mid 30s. another dry trough of low pressure will move through Wednesday with similar characteristics as it, too, will have dry and relatively cold air moving down from the north behind the front.
Models for the period beginning the 22 have in some cases reverted back to a potential freeze configuration. On paper, a strong upper high is projected to build far to the north, almost to the Arctic Circle. Models this morning, or at least some, had shown this air moving in a bit further to the east. This afternoon, though, a cold low is shown over Arizona. Between the upper high and the low to our southeast, a train of cold air may become entrenched moving into California. If this occurs, at least widespread low to mid 20s would happen, giving us some long hours just before Christmas. At any rate, plenty could change between then and now.
Forecast: Increasing high and mid level clouds, especially later tonight and early Saturday morning, then clearing. Mostly clear Saturday afternoon through Tuesday night. partly cloudy Wednesday and Wednesday night. becoming mostly clear Thursday and Friday.
Short Term:
| Madera 38/60/28/60 | Reedley 37/59/28/59 | Dinuba 37/60/27/61 | |
| Porterville 36/60/28/62 | Lindsay 37/60/27/60 | Delano 38/61/29/61 | |
| Bakersfield 39/61/33/62 | Arvin 36/62/29/63 | Taft 41/61/34/63 | |
| Lamont 38/62/30/63 | Pixley 36/61/28/61 | Tulare 36/60/27/61 | |
| Woodlake 37/61/29/61 | Hanford 37/60/28/61 | Orosi 35/59/28/60 | |
Winds: winds will generally be light before midnight. Late tonight and Saturday, winds along the west side will pick up to 15 to 25 MPH with gusts of more than 30 MPH, especially along the Interstate 5 corridor. Winds elsewhere tomorrow will be mainly out of the northwest at 10 to 15 MPH with stronger gusts. Winds will begin to decrease later Saturday evening and become generally light after midnight Saturday night. Winds Sunday through Tuesday will be generally less than 10 MPH with periods of near calm conditions.
Rain: Expect dry weather for at least the next seven to ten days.
Frost Information: High clouds are already increasing ahead of a fast moving trough of low pressure and associated cold front which will move through the valley during the early morning hours Saturday. The cloud cover along with mixing of the atmosphere will keep most locations above freezing tonight, however if these clouds are too thin, coldest locations could dip into the lower 30s.
Behind the front will be a cold northerly flow aloft which will inject colder air onto the valley floor along with bringing about some gusty winds. For now, it appears the winds will be near calm after midnight Saturday night, switching us back to mid 20s to lower 30s and that will be the way of life through Tuesday morning.
A similar weak, dry trough passage could keep temperatures up Wednesday, but behind it will also be another northerly flow, maintaining chilly overnight low temperatures.
Now we look at the pattern for the 22 through Christmas Day and possibly beyond. Most modeling information this afternoon have reverted back to a configuration which could lead to a hard freeze. The two main players will be an upper high building a ridge far to the north and a developing low possibly centering over northwest Mexico or Arizona. The upper high could potentially transfer northern Canadian air into the west and quite possibly California. The low to our south would generate a very strong off shore flow with strong Santa Ana winds to our south. This is a freeze scenario which could lower temperatures into the low to mid 20s and possibly even colder. As we’ve been discussing the past few days, modeling information will change from run to run. I was half way encouraged this morning, and now I’m half way discouraged. I’m not ready to call for a freeze at this time, just want you to be aware of the players.
Lows Tonight:
| Terra Bella
32 |
Porterville
AF |
Ivanhoe
AF |
Woodlake
AF |
| Strathmore
AF |
McFarland
32 |
Ducor
AF |
Tea Pot Dome
AF |
| Lindsay
31 |
Exeter
32 |
Famoso
AF |
Madera
AF |
| Belridge
AF |
Delano
AF |
North Bakersfield
AF |
Orosi
32 |
| Orange Cove
AF |
Lindcove
31 |
Lindcove hillside
AF |
Sanger River Bottom
29 |
| Root Creek
31 |
Venice Hill
AF |
Rosedale
AF |
Jasmine
AF |
| Arvin
AF |
Lamont
AF |
Plainview
AF |
Mettler
AF |
| Edison
AF |
Maricopa
AF |
Holland Creek
AF |
Tivy Valley
AF |
| Kite Road South
AF |
Kite Road North
AF |
Next Report: Saturday morning/December 16