February 21, 2019
Summary: The air mass is currently very cold. The freezing level at Oakland and Vandenberg was just 3,600 feet. As of 1:00pm, light snow was being reported at the bottom of the Grapevine with a temperature of 34. The air mass over the valley portion of Kern County, even in the lowest elevations, was only in the low to mid 40s as of 1:00pm. Once you get to Merced and points north, readings were in the low to mid 50s. showers have extended in the south valley longer than anticipated due to the slow movement of the modified arctic low currently in southern Nevada. Snow has been reported today at Las Vegas. The low will move into western Arizona and southern California Friday then will move eastward through the Desert Southwest over the weekend.
The next challenge will be subfreezing temperatures tonight and again Friday night. a lot of complications are in the frost forecast and they’re discussed below.
A fundamental change will occur in the overall pattern beginning Sunday as a flat zone of high pressure extends from the eastern Pacific eastward into the Desert Southwest while an elongated low will stretch from Montana to off shore Washington. This same basic pattern will continue through Wednesday and will generate a westerly flow into California with periods of showers from Sunday night through midweek down to a Monterey/Merced/Yosemite line. There’s a slight chance of showers down to Fresno County.
Upper level high pressure will upwell over California Thursday and Friday ahead of a much warmer Pacific low which will approach the northern California coast Friday night and Saturday. For the first week in March, models are still pointing towards a big low off the Oregon/northern California coast with a moist westerly flow underneath this low and into California. Waves of low pressure will be embedded within this flow, resulting in periodic chances of rain. Because the flow will be out of the west to, even occasionally, out of the southwest, snow levels will be relatively high. However, it will also allow these systems to carry a considerable amount of water, especially up over the west facing slopes of the Sierra Nevada.
The new two week outlook is suggesting above average temperatures with a good chance of rain.
Forecast: A chance of widely scattered showers, mainly in Kern County, for a time this evening, possibly mixed with a little snow after sunset. Expect dry weather to return by this evening. Otherwise, skies will be clearing with cold conditions tonight. Some cloud cover may remain over Tulare and Kern Counties until after sunrise. Becoming mostly clear Friday through Saturday night. cold again Saturday morning. Variable cloudiness at times Sunday night through Thursday with a slight chance of showers Sunday night through Wednesday from Fresno County north.
Short Term:
| Madera 28/54/29/57 | Reedley 28/55/29/58 | Dinuba 28/53/28/57 | |
| Porterville 29/55/29/58 | Lindsay 28/54/28/59 | Delano 29/54/29/58 | |
| Bakersfield 33/56/32/60 | Taft 31/56/33/59 | Arvin 30/56/29/60 | |
| Lamont 30/56/30/60 | Pixley 29/55/29/57 | Tulare 28/54/29/57 | |
| Woodlake 28/55/29/58 | Hanford 29/55/29/58 | Orosi 28/54/29/57 | |
Winds: Winds will be out of the northwest at 10 to 15 MPH this evening with gusts to 25 MPH along the west side. Winds will be light and variable to near calm after midnight. Winds Friday will be mainly out of the northwest at 5 to 12 MPH then generally less than 6 MPH Friday night with periods of near calm conditions. Winds Saturday and Sunday will be variable at 5 to 12 MPH during the afternoons and evenings and less than 7 MPH with periods of near calm conditions during the night and morning hours.
Rain: There is still a chance of light showers over Kern County for a time this evening with possibly even some snow flakes reaching the ground after sunset. All the activity should be over by 9:00 or 10:00pm with dry weather through Sunday. From Sunday night through Wednesday, there will be a small chance of light showers as far south as Fresno County, but more realistically, it appears the rain line will be near a Monterey/Merced/Yosemite line. Beginning Friday night of next week and beyond, there will be a chance of periodic bouts of precipitation as waves of milder low pressure race in from the west underneath a storm off the coast of Oregon and northern California. These systems will be much milder than we’ve bee accustomed to and could be carrying more water.
Frost Discussion: The freezing level at both Oakland and Vandenberg earlier today stood at 3,600 feet and, with snow being reported at places such as Las Vegas and the bottom of the Grapevine, you get a good idea of the air mass we’re currently dealing with. Where it clears tonight, especially in Madera, Fresno, and Kings Counties, lows from 27 to 30 will be common with similar conditions where skies clear in Tulare and Kern Counties. It’s possible some cloud cover could remain over Kern County and portions of Tulare County for much of the night due to upsloping, but each system has its own personality, so where it clears, isolated pockets could lower to near 26 with readings of 28 to 31 being more common where it clears over generally flat topography.
The inversion will be weak tonight with temperatures at 34 feet only 1 to 4 degrees warmer. Coldest unprotected low spots could reach 32 degrees by 9 or 10 pm and 28 degrees by 3:00am. Temperatures will not rise to above freezing until 8:30 to 9:00am Friday. Even though I do anticipate some moderation in daytime highs tomorrow, Saturday morning should be just as cold, possibly a degree or two colder in Kern County, assuming clouds hang in there tonight.
The good news is this should be it. There will be a chance of a few lower 30s Sunday morning, but the long awaited westerly flow will begin Sunday and will be the dominant flow next week, pumping in much warmer air both at the surface and aloft. There’s nothing on medium range models indicating a return to an unusually cold pattern.
Lows Tonight:
| Terra Bella
29 |
Porterville
28 |
Ivanhoe
27 |
Woodlake
29 |
| Strathmore
29 |
McFarland
29 |
Ducor
29 |
Tea Pot Dome
29 |
| Lindsay
27 |
Exeter
28 |
Famoso
29 |
Madera
28 |
| Belridge
27 |
Delano
29 |
North Bakersfield
30 |
Orosi
28 |
| Orange Cove
29 |
Lindcove
27 |
Lindcove Hillside
31 |
Sanger River Bottom
25 |
| Root Creek
27 |
Venice Hill
28 |
Rosedale
30 |
Jasmine
29 |
| Arvin
30 |
Lamont
30 |
Plainview
28 |
Mettler
31 |
| Edison
30 |
Maricopa
30 |
Holland Creek
31 |
Tivy Valley
28 |
| Kite Road South
30 |
Kite Road North
28 |
AF=Above Freezing
Next report: Friday morning/February 22