November 20, 2018
Summary: Upper level high pressure remains over California but is slowly weakening. There are subtle signs that changes are occurring. Temperatures are 5 to 8 degrees warmer at this hour than they were 24 hours ago. Many locations in Kern County have jumped up into the mid 70s with readings moving into the lower 70s elsewhere. Also, I’ve picked up on the fact that strong, gusty east to southeast winds are buffeting the Tehachapi Mountains. Winds above the top of the Grapevine are gusting to 46 MPH while at the bottom of the Grapevine at the CHP office, winds are out of the southeast sustained at 22 and gusting to 35 MPH.
As the low slowly approaches the coast, precipitation will spread in from the west, covering the entire valley and reaching Kern County last, probably by late afternoon or evening Wednesday. Precipitation will continue at times Wednesday night and for the first half of the day Thanksgiving Day. Precipitation has the potential to be locally heavy along the east side, mainly east of Highway 99 and north of a Visalia/Exeter line with lesser amounts further south. Rain shadows will develop along the Coast Range and over the valley portion of Kern County, reducing rainfall amounts there. This is typical with stronger winter storms.
The rain will taper off by Thursday afternoon, but the chance of lighter showers will pick up later Thursday night and on and off through Saturday morning as a second system moves inland with the main energy moving into northern California from roughly a Monterey/Merced/Yosemite line north. Lighter showers, however, will be possible for the entire region with the greatest potential being from Fresno County north.
Upper level high pressure will begin to build behind that second system Saturday afternoon then will set up shop along and over the west coast, shoving the storm track back into the Pacific Northwest. This does not appear to be the beginning of another long dry spell, however, as models continue to hold onto the idea of a big trough developing along the west coast with its center off the coast of the Pacific Northwest while a strong westerly flow moves underneath the low and into California. This historically is a good pattern for multiple storms to affect our region. The fact that the medium range outlooks have been trending recently gives me a greater level of confidence that wet weather may be a reality for late November and early December.
Forecast: Mostly clear before midnight. Increasing cloudiness during the early morning hours. Rain spreading over the valley Wednesday afternoon. Rain at times Wednesday night and Thanksgiving morning, locally heavy at times. Mostly to partly cloudy Thursday afternoon and evening with a chance of showers late Thursday night through Saturday morning. The greatest potential for rain will be from Fresno County north. Partly cloudy Saturday afternoon through Sunday morning with the exception of Kern County and portions of Tulare County which will remain mostly cloudy through at least midday Sunday. Mostly clear Sunday afternoon through Tuesday with areas of night and morning fog and/or low clouds.
Short Term:
| Madera 38/65/49/61 | Reedley 35/66/48/62 | Dinuba 34/67/47/61 | |
| Porterville 34/70/49/62 | Lindsay 32/70/49/63 | Delano 37/71/50/62 | |
| Bakersfield 45/73/51/62 | Arvin 41/75/51/62 | Taft 48/72/52/62 | |
| Lamont 41/73/51/63 | Pixley 34/65/49/62 | Tulare 32/66/47/61 | |
| Woodlake 34/68/48/61 | Hanford 37/68/49/62 | Orosi 32/68/47/61 | |
Winds: Winds will have to be monitored closely tonight and Wednesday in the extreme south valley. I noted this afternoon that over the Tehachapi Mountains, winds were in the 25 to 40 MPH range out of the east to southeast and at last report, winds were gusting to 46 MPH at the top of Grapevine Peak. Southeast winds have worked their way down to the CHP office at the bottom of the Grapevine where wind at last report were sustained at 22, gusting to 35 MPH. The fact that these winds have reached the lip of the valley floor is of some concern. Even though models don’t really suggest wind problems in Kern County, they’re already pretty close to the valley floor although no location, as of this time, that I know of was experiencing wind challenges. Still, I do want to introduce that possibility of gusty southeast winds possibly making it several miles out onto the valley floor. Areas of greatest risk would be near Arvin and Edison, sweeping along the base of the mountains to near Taft. For now, I would put the chance of these winds developing at no more than 20% to 30%. North of Kern County, winds will be generally less than 10 MPH tonight and becoming out of the southeast by sunrise.
Winds Wednesday through Friday will be generally out of the southeast at 5 to 15 MPH with local gusts to 25 MPH, mainly from Fresno County north.
Rain: The chance of rain will increase dramatically from midday Wednesday north of Kern County, reaching Kern County during the late afternoon through the early evening. Expect rain at times Wednesday night and Thanksgiving morning then there will be a brief dry slot Thursday afternoon through most of Thursday night. The chance of lighter precipitation in the form of showers will arrive late Thursday night and continue on and off into Saturday morning. A short period of dry weather will set up Saturday afternoon.
Rainfall amounts over Madera County and eastern Fresno and Tulare Counties generally east of Highway 99 and north of a Visalia/Exeter line should tally up to between .33 and.75. Over southeastern Tulare County, .25 to .33 is likely. Along the west side, .25 to .33 is possible, although that’s a low confidence forecast because of the rain shadows that will no doubt develop. Rainfall over the valley portion of Kern County will generally range at or less than .25.
Again, dry weather will begin Saturday afternoon and continue for much of next week. That may sound a bit ominous, but the good news is that models are continuing to suggest multiple opportunities for wet weather beginning the 28 and lasting through the first week of December. The pattern which may be setting up is a deep trough west of Washington state and Vancouver Island with a strong west to east jet stream moving into northern and central California. Historically, this pattern has produced generous amounts of rain. If this does set up, we would probably see a day or two between storms, perhaps three days, before action sets up anew. Let’s keep our fingers crossed.
Frost Information: Temperatures are anywhere from 5 to 8 degrees warmer than 24 hours ago. Dew points are still quite low, ranging in the low to mid 30s. downslope winds are occurring off the Tehachapi Mountains. They’ve driven temperatures into the mid 70s at many locations south of the Kern County line and even further north, significant warming has occurred. This is due to an intensifying low several hundred miles off shore which is creating weak downslope winds off the Sierra Nevada and, in some cases, strong downslope winds in Kern County. I believe this will preclude any chance of frost tonight, though it’s possible that in eastern and southeastern Tulare County, pockets of stable weather and low dew points may allow a few locations to move into the lower 30s, though don’t be surprised if all locations are above 32 tonight.
Looking ahead through the remainder of the week and the middle of next week, no significantly cold weather is expected. Medium range models for the end of the month and the first week in December are indicating the possibility of a strong westerly flow aloft into California. This would ensure relatively mild conditions.
Lows Tonight:
| Terra Bella
32 |
Porterville
Af |
Ivanhoe
33 |
Woodlake
34 |
| Strathmore
33 |
McFarland
Af |
Ducor
Af |
Tea Pot Dome
Af |
| Lindsay
32 |
Exeter
32 |
Famoso
Af |
Madera
Af |
| Belridge
Af |
Delano
Af |
North Bakersfield
Af |
Orosi
33 |
| Orange Cove
33 |
Lindcove
32 |
Lindcove Hillside | Sanger River Bottom
Af |
| Root Creek
Af |
Venice Hill
33 |
Rosedale
Af |
Jasmine
Af |
| Arvim
Af |
Lamont
Af |
Plainview
33 |
Mettler
Af |
| Edison
Af |
Maricopa
Af |
Holland Creek
Af |
Tivy Valley
af |
| Kite Road South
Af |
Kite Road North
32 |
AF=Above Freezing
Next Report: Wednesday morning/November 21