December 10, 2020
The low pressure system which yesterday at this time was off the northern Baja, California coastline has now moved east/northeast into southern Arizona. This system is being nudged eastward by a fast moving system which will move through the Pacific Northwest today and into the Great Basin Friday. As this system slides southeastwards to our east, a dry cold front will move down the valley late this afternoon and tonight, issuing in a cooler air mass, but no precipitation. The northwest flow aloft following this system will kick up the winds somewhat along the west side of the valley and may form a layer of upslope clouds against the north facing slopes of the Tehachapi Mountains and the west facing slopes of the southern Sierra Nevada, mainly in Tulare County. Skies will clear out Friday morning.
The pattern for Friday night through Monday indicates the eastern Pacific high will slide farther off shore as a series of low pressure systems moves through the Pacific Northwest and northern California. It’s possible a few light showers could struggle as far south as Fresno County. It appears there’s two opportunities for this to occur. The first will be later Friday night and Saturday morning. the second will be late Sunday afternoon into Monday morning. with the developing onshore flow, dew points will rise and with increased cloud cover, the long string of subfreezing nights will come to an end Saturday morning.
If precipitation does occur on the valley floor, no more than .10 can be expected in Merced County and perhaps a few hundredths as far south as Fresno County with the south valley remaining dry. After Monday, the eastern Pacific high will again build along the west coast, shunting the next series of storms well to our north. Most models maintain a dry forecast through next week. Although the GFS model shows a rather vigorous system affecting northern and central California about the middle of next week.
Forecast: Partly cloudy today. Mostly clear tonight and Friday except possibly mostly cloudy in portions of Kern County and eastern Tulare County later tonight through Friday morning. Mostly clear Friday afternoon. Becoming mostly cloudy later Friday night and Saturday with a small chance of sprinkles or light showers as far south as Fresno County later Friday night and Saturday morning. variable cloudiness Saturday night through Monday morning. mostly cloudy Sunday afternoon through Monday with a small chance of sprinkles or light showers from Fresno County north Sunday night and Monday morning. Partly cloudy Monday night through Thursday.
Short Term:
| Madera 62/29/56/34/57 | Reedley 63/28/55/33/57 | Dinuba 62/28/56/32/57 |
| Porterville 63/28/57/34/57 | Lindsay 63/28/56/34/57 | Delano 63/29/56/34/58 |
| Bakersfield 62/40/56/41/56 | Taft 62/44/56/46/57 | Arvin 63/33/56/37/57 |
| Lamont 62/32/56/37/56 | Pixley 63/28/56/34/58 | Tulare 61/27/55/33/57 |
| Woodlake 62/28/56/35/56 | Hanford 63/30/56/36/57 | Orosi 62/37/56/34/57 |
Seven Day Forecast:
| Sunday
PM light showers possible 41/58 |
Monday
AM showers possible 39/62 |
Tuesday
Partly cloudy 36/59 |
Wednesday
Partly cloudy 32/64 |
Thursday
Partly cloudy 33/60 |
Two Week Outlook: December 17 through December 23: This model has reverted back to the blocking ridge pattern which drives storms well to our north. With a dome of high pressure above, expect daytime highs to remain above average.
December: This model shows above average temperatures during the month of December. Southern California should experience below average precipitation. There is some hope for northern and central California, however, as this model spits out equal chances of above or below average rainfall. We’re hoping for the above average side of things.
December, January, February: This model definitely reflects a La Nina pattern, which is when ocean temperatures are below average through the equatorial waters off of Peru, extending into the mid Pacific. Typically, this results in above average temperatures for much of the southern half of the U.S., including California, with unfortunately below average precipitation for California including the valley.
Winds Discussion: Winds through Sunday will be variable to no more than 10 MPH late mornings and afternoons. During the night and early morning hours, winds will be no more than 6 MPH with periods of near calm conditions. However, tonight through Friday morning, winds, mainly along the I-5 corridor, will be at 8 to 15 MPH with stronger gusts.
Rain Discussion: It appears there will be two opportunities for measurable rain from Fresno County north. The first will be later Friday night and Saturday morning. Even though the chance is low, even from Fresno County north, it is worth mentioning. No more than a few hundredths could be expected with possibly about .10 up in Merced County. The second minimal chance will be late Sunday afternoon through Monday morning. again, this will be a Fresno County northward affair, if it happens at all. Generally less than .10 can be expected. After Monday morning, dry weather shows up on most models for the remainder of the week.
There is one exception, however, and that is the GFS model which shows a low trying to develop over northern California for a chance of rain.
Frost Discussion: Low 30s were widespread again last night. there were a few exceptions. Famoso was the coldest I could find at 27 as of 6:30am, while Ivanhoe, Lindcove, and McFarland came in at 29.
Tonight could potentially end up 2 to 3 degrees cooler at most locations as the cloud cover we enjoyed from time to time last night will not be available. However, there is a wild card. As a direct cold front moves through the valley late this afternoon through tonight, it’s possible there may be enough midlevel moisture for form clouds against the north facing slopes of the Tehachapi and, to a lesser extent, the southern Sierra Nevada. Where these clouds develop, temperatures could end up above freezing, however for tonight I’m not counting on them and am going with the clear skies scenario which means unprotected frost pockets could potentially drop to 25 ot 26 with most flat land locations between 27 and 31.
The inversion tonight will be decent early but will begin to weaken later in the night with temperatures at 34 feet generally 3 to 6 degrees warmer.
We may very well see above freezing conditions Saturday morning as clouds move in ahead of systems moving into the Pacific Northwest and northern California. This will lead into several nights of above freezing weather through at least Tuesday of next week. For now, there’s nothing showing up longer term which would favor a freeze situation.
Air Quality Expectations: The San Joaquin Valley Air Pollution Control District has issued the following warning(s) for December 10, 2020:
Today’s air quality is listed as moderate for Merced County. The air quality for the remainder of the valley is Unsafe for Sensitive Groups.
The District’s Real-time Air Advisory Network (RAAN) can be used to track air quality at any Valley location by visiting myRAAN.com. The option to use a specific address is available.
For more information on wildfires affecting the Valley’s air, visit: http://www.valleyair.org/wildfires
In addition, anyone can follow air quality conditions by downloading the free “Valley Air” app on their mobile device
Afternoon Dew Points Today: Mid to upper 30s. Kern, Low to mid 30s.
Actual Humidity Range Yesterday: Delano, 98%/26% Porterville, NA
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 70%, tomorrow 90%. Bakersfield: Today: 70% Tomorrow: 90%
ET Rates Over the Past Seven Days: Stratford .49, Parlier .46, Blackwell Corners .NA, Arvin .62, Orange Cove .49, Porterville .NA, Delano .43. Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 54, Parlier 50, Blackwell 56, Arvin, 52, Orange Cove 55, Porterville 51, Delano NA
Record Temperatures: 74/26. Average Temperatures: 56/34
Heating Degree Days This Season: 557, -115
Courtesy of the NWS
Average Temperature for this month So Far: 48.8 +2.8
Precipitation: Seasonal total for Fresno, .28, -1.83, Month to Date: .00, -.41
Precipitation for Bakersfield, Season, .39, +or- -.80. Month to date .00, -.25
Water year season is from October 1st through September.
Chilling Hours November 1st through February 28: Orange Cove, 296, Parlier, 366, Arvin, 276, Shafter, 306, Stratford, 339, Delano, 356, Lindcove, NA, Porterville, 402
Hours at 45 or below 45. Courtesy UC Davis
Sunrise: 7:02 am Sunset: 4:43 pm Hours of Daylight: 9:42
Yesterday’s Weather
MCE : Merced 153 : DH1600 / 64 / 38 / 0.00 /
MAE : Madera 253 : DH1600 / 68 / 38 / 0.00 /
FAT : Fresno Airport 333 : DH1600 / 69 / 43 / 0.00 /
HJO : Hanford Airport 242 : DH1600 / 66 / 36 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1600 / M / M / 0.00 /
BFL : Bakersfield Airport 496 : DH1600 / 66 / 40 / 0.00 /
VIS : Visalia Airport 292 : DH1600 / 66 / 32 / 0.00 /
PTV : Porterville Airport 442 : DH1600 / 65 / 33 / 0.00 /
LOSC1 : Los Banos 120 : DH1600 / 59 / 35 / 0.00 /
Rainfall: 24hr W.Y. % Last Y. % Ave. Year ave.
STOCKTON 0.00 0.09 3 3.90 127 3.08 14.06
MODESTO 0.00 0.10 4 2.75 108 2.54 13.11
MERCED 0.00 1.08 48 4.52 199 2.27 12.50
MADERA 0.00 0.16 7 1.90 81 2.36 12.02
FRESNO 0.00 0.28 13 2.47 117 2.11 11.50
HANFORD 0.00 0.13 8 1.75 102 1.72 10.10
BAKERSFIELD 0.00 0.39 33 1.58 133 1.19 6.47
BISHOP 0.00 T 0 1.06 107 0.99 5.18
SALINAS 0.00 0.37 15 4.09 165 2.48 12.83
PASO ROBLES 0.00 0.28 13 4.70 225 2.09 12.78
SANTA MARIA 0.00 0.25 10 2.68 110 2.44 13.95
Lows Tonight:
| Terra Bella
28 |
Porterville
28 |
Ivanhoe
26 |
Woodlake
27 |
| Strathmore
28 |
McFarland
27 |
Ducor
29 |
Tea Pot Dome
28 |
| Lindsay
28 |
Exeter
27 |
Famoso
28 |
Madera
29 |
| Belridge
31 |
Delano
28 |
North Bakersfield
28 |
Orosi
27 |
| Orange Cove
28 |
Lindcove
27 |
Lindcove Hillside
Af |
Sanger River Bottom
25 |
| Root Creek
26 |
Venice Hill
28 |
Rosedale
29 |
Jasmine
29 |
| Arvin
33 |
Lamont
32 |
Plainview
28 |
Mettler
32 |
| Edison
32 |
Maricopa
28 |
Holland Creek
31 |
Tivy Valley
28 |
| Kite Road South
31 |
Kite Road North
28 |
AF=Above Freezing
Next report: December 10/pm