December 28, 2018
Summary: Skies are generally clear this afternoon with the exception of a few small pockets of clouds in Kern County which will no doubt dissipate this afternoon and evening. We are in for a couple of cold nights ahead as low pressure centered over northeast Arizona and an upper level high which extends into British Columbia now have the winds aloft out of the northeast. This continues to pump cold, dry air down the Sacramento Valley then down the west side of the San Joaquin Valley. Most locations in the Sacramento Valley have winds out of the north at between 10 and 20 MPH with winds along the west side generally in the 10 to 15 MPH range out of the north.
Mid to upper 20s will be widespread tonight and tomorrow night. this is discussed in detail in the frost discussion below.
By late Sunday, high pressure off shore will begin nosing into northern and central California. This will change the winds aloft from northeasterly to northwesterly, which is a huge difference. However, with cold and relatively dry air trapped on the valley floor, a series of nights below freezing can be expected. New Year’s Day and the day afternoon will have a north/south flow into the western United States.
Some models this afternoon do not show the eastern Pacific high building into the Yukon Territory. Instead, they show it building into British Columbia and the Canadian Rockies. This will definitely bring a north/south modified arctic air mass into the west, but certainly not as cold as it could have been if the high had managed to get into Alaska or the Yukon territory. This flow will be very temporary. By the third, the eastern Pacific high will begin to build eastward, turning the winds aloft out of the west by midweek and pumping much milder air in aloft. Hopefully it will mix down to the surface.
Some models point to January 6 as a turnaround day in the pattern which could result in lower latitude storms affecting California. It’s still too far away to nail it down with any accuracy, but it is the second day in a row some models have been pointing in that direction.
Forecast: Outside of occasional high clouds and areas of later night through midmorning fog, it will be mostly clear through New Year’s Day. Mostly clear Tuesday night through Thursday. Increasing cloudiness Friday.
Short Term:
| Madera 27/53/28/54 | Reedley 27/54/27/54 | Dinuba 26/53/27/53 | |
| Porterville 27/54/27/55 | Lindsay 26/53/27/54 | Delano 28/53/29/55 | |
| Bakersfield 32/55/33/56 | Taft 30/55/32/55 | Arvin 28/54/29/55 | |
| Lamont 29/54/29/55 | Pixley 26/53/27/54 | Tulare 26/53/27/54 | |
| Woodlake 27/53/27/54 | Hanford 27/53/28/54 | Orosi 26/53/27/54 | |
Winds: Winds tonight will generally be less than 7 MPH with prolonged periods of near calm conditions. Similar conditions can be expected Saturday through Sunday. By Monday and into New Year’s morning, we may see some gusty north to northwest winds along the west side of the valley with generally light winds elsewhere.
Rain: Expect dry conditions for the next seven to ten days.
Frost Discussion: Temperatures as of 1:00pm ranged in the upper 40s to the lower 50s. Dew points had fallen into the low to mid 30s. just to our north, the lower Sacramento Valley and northern San Joaquin Valley were reporting dew points in the upper 20s. No doubt about it, a cold dry air mass has arrived. Skies are generally clear which will lead to a strong radiational freeze event tonight through at least Sunday morning. The coldest locations will drop down to 24 to 25 degrees in unprotected low lying river bottom and similar locations. Most flat terrain will chill down to 26 to 29 degrees with hillsides generally in the low to mid 30s. the inversion tonight will be moderate with temperatures at 34 feet from 3 to 7 degrees warmer at most locations.
Temperatures at the very coldest locations will drop to the freezing mark around nine or ten o’clock and down to 28 degrees around 2:00 to 3:00am. Temperatures won’t rise above that level until 8:30 or 9:00 Saturday morning. Sunday morning will be equally as cold, though some moderation will occur in the daytime highs. Monday morning is a bit more difficult to forecast as a low center will develop over Arizona and the eastern Pacific high will drive northward into western Canada.
Most models this afternoon do not indicate the high will ridge into Alaska or the Yukon Territory. Thus, the north to south flow that will occur New Year’s Eve and Day doesn’t look quite as ominous as 24 hours ago. Nevertheless, mid to upper 20s are certainly possible New Year’s Day and Wednesday. By the time we get to Thursday, the eastern Pacific high will be moving eastward into California, turning the winds aloft west to east, which is a much milder flow.
Medium range models also appear much milder with generally a west to southwest flow. There may even be an increased chance of rain after about January 6.
Lows Tonight:
| Terra Bella
27 |
Porterville
27 |
Ivanhoe
25 |
Woodlake
27 |
| Strathmore
26 |
McFarland
26 |
Ducor
28 |
Tea Pot Dome
28 |
| Lindsay
26 |
Exeter
25 |
Famoso
28 |
Madera
27 |
| Belridge
26 |
Delano
28 |
North Bakersfield
29 |
Orosi
26 |
| Orange Cove
28 |
Lindcove
26 |
Lindcove Hillside
31 |
Sanger River Bottom
24 |
| Root Creek
25 |
Venice Hill
28 |
Rosedale
29 |
Jasmine
28 |
| Arvin
28 |
Lamont
28 |
Plainview
27 |
Mettler
30 |
| Edison
28 |
Maricopa
26 |
Holland Creek
29 |
Tivy Valley
26 |
| Kite Road South
30 |
Kite Road North
28 |
AF=Above Freezing
Next report: Saturday morning/December 29