December 25, 2020
It is a cold, frosty, Christmas morning our there with widespread upper 20s and low 30s. after that weak upper low moved through southern California overnight, skies cleared, allowing for decent radiational cooling. Clouds will increase today ahead of a trough of low pressure which will move through northern and central California tonight and Saturday morning. light showers are showing up off shore west of Monterey, but it will be evening before the chance of light showers enters the picture here. Models continue to show the southern portion of this trough to be quite weak, so only a chance of light showers is anticipated, mainly from Fresno County north.
The next system upstream has its origins in the Gulf of Alaska and will drop southeastward, centering just west of San Francisco by midnight Sunday night. it’s possible pressure differences at the surface may be enough for localized strong, gusty winds in the extreme south valley, mainly Sunday afternoon and night. models indicate the center of circulation will be almost right overhead by midday Monday with widespread precipitation. Since this system’s origins are in the Gulf of Alaska, the snow level will drop to around 3,500 feet along the southern Sierra Nevada and over the Kern County mountains Monday. The low will continue to weaken, moving through southern California Monday night and into the Desert Southwest Tuesday.
From Tuesday night through much of the first week of the New Year, a flat zone of upper level high pressure will stretch from the eastern Pacific across the southern 2/3 of California. The Pacific Northwest will continue to be pummeled by storm after storm generally running on a zonal flow. Models do bring the southern limit of the precipitation as far south as a Monterey/Merced line on New Year’s Day with possibly similar events later in the week.
Assuming we get a soaking rain Sunday night and Monday, fog and low clouds will enter the picture by midweek. However, with the storm track just to our north, it’s possible there will be enough mixing in the atmosphere to possibly interfere with a full fledged fog regime.
Forecast: Areas of fog and low clouds north of Kern County this morning. otherwise, expect increasing cloudiness. Cloudy tonight through Saturday with a chance of light showers from Fresno County north. Sprinkles are possible in the south valley. Partly to mostly cloudy Saturday night and Sunday morning. increasing cloudiness Sunday afternoon with a chance of rain from Fresno County north by midafternoon. Rain likely at times Sunday night through Monday morning. Showers likely Monday afternoon, tapering off Monday evening. Mostly cloudy Monday night and Tuesday morning. mostly clear to occasionally partly cloudy Tuesday afternoon through New Year’s Day with areas of night and morning fog and low clouds.
Short Term:
| Madera 60/41/59/37/56 | Reedley 62/40/60/39/55 | Dinuba 61/41/60/39/56 |
| Porterville 64/42/61/39/55 | Lindsay 63/41/60/39/56 | Delano 63/42/61/40/55 |
| Bakersfield 67/46/60/42/58 | Taft 66/51/58/47/57 | Arvin 66/43/60/42/59 |
| Lamont 67/44/59/44/58 | Pixley 64/42/61/39/56 | Tulare 61/40/60/38/55 |
| Woodlake 62/40/60/38/55 | Hanford 63/42/60/40/56 | Orosi 61/40/60/38/55 |
Seven Day Forecast:
| Monday
Rain likely 41/52 |
Tuesday
Mostly cloudy 34/54 |
Wednesday
AM fog/partly cloudy 33/54 |
Thursday
AM fog/partly cloudy 33/53 |
Friday
AM fog/mostly cloudy 37/56 |
Two Week Outlook: December 31 through January 6: This model shows an active pattern moving through the Pacific Northwest and northern California with central California being on the dividing line between wet weather to our north and dry weather to our south. We would at least have a chance of rain during this period with below average temperatures.
January: This model doesn’t really show a trend for temperatures at all. We’ll call it near average this time around. Not surprisingly, it does indicate January will have below average precipitation, as has been the case this La Nina year.
January, February, March: This model does not really offer much hope for a decent rainy season as below average precipitation is indicated over the Golden State. Temperatures over this 90 day period will be generally above seasonal average.
Winds Discussion: Winds later today and tonight will be mainly out of the southeast at 5 to 12 MPH. Winds Saturday will be generally out of the southeast at 8 to 15 MPH, diminishing Saturday night. Later Sunday, winds will be out of the east to southeast at 8 to 15 MPH. gusts to 25 MPH will be possible, mainly from Fresno County north and along the west side. There is a small chance of strong, gusty, downslope winds in the extreme south valley Sunday afternoon and Sunday night. later Monday, winds will be out of the northwest at 10 to 20 MPH.
Rain Discussion: There is a chance of light showers, mainly from Fresno County northward, tonight and Saturday morning. even from Fresno County north, precipitation amounts will likely be less than .10. Dry weather will return later Saturday afternoon through Sunday morning. a considerably stronger storm will drop out of the Gulf of Alaska and will move through southern and central California Sunday night through Monday evening. This storm is colder and will drop snow levels down to about 3,500 feet in the surrounding mountains. This time around, finally, precipitation will be widespread. Rain may reach Fresno County by midafternoon Sunday, spreading over the rest of the valley Sunday night. the rain will taper off Monday evening. Rainfall amounts from this storm could add up to .25 to .33 north of Kern County with locally more. In Kern County, possibly as much as .25 could accumulate. Dry weather will return Monday night. models show a very active storm track moving from west to east into the Pacific Northwest and parts of northern California from time to time from Wednesday through next weekend. So far, the southern limit of the precipitation will remain just to our north, although I wouldn’t completely rule out a chance of showers from Fresno County north on January 1. Generally speaking, however, it appears the southern half of California will remain dry after Monday’s event through the first week of January.
Frost Discussion: My Christmas present to you is all locations will be above 32 degrees tonight and each night through Monday morning and possibly Tuesday morning. a cold Gulf of Alaskan storm will move through here Sunday night and Monday. Following this system will be a north/northwest flow aloft with a relatively cold air mass moving in. however, it’s nothing unusual by the standards of the season. From the middle of next week and beyond, any clear night has the potential of upper 20s and lower 30s. the storm track will move sweeping through the Pacific Northwest and northern California from time to time, meaning there may be variable cloudiness from time to time. Also, assuming we get a good soaking Sunday night and Monday, a wet valley floor will increase the possibility of fog and low clouds nights and mornings. This will be a tricky one as the storm track will be close enough to possibly add mixing to the atmosphere, preventing a full fledged fog regime. Medium range models do not show a pattern which would be conducive for particularly cold weather.
Air Quality Expectations: The San Joaquin Valley Air Pollution Control District has issued the following warning(s) for December 25, 2020:
The air quality for Fresno County is unsafe for sensitive groups. The air quality in the remainder of the region is moderate.
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.
In addition, anyone can follow air quality conditions by downloading the free “Valley Air” app on their mobile device
Afternoon Dew Points Today: Low to mid 40s. Kern, mid to upper 20s.
Actual Humidity Range Yesterday: Delano, 99%/44% Porterville, NA
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 20%, tomorrow 30%. Bakersfield: Today: 20% Tomorrow: 30%
ET Rates Over the Past Seven Days: Stratford .24, Parlier .27, Blackwell Corners .NA, Arvin .39, Orange Cove .22, Porterville .NA, Delano .23. Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 53, Parlier 49, Blackwell 55, Arvin, 51, Orange Cove 52, Porterville 51, Delano 44
Record Temperatures: 72/20. Average Temperatures: 53/35
Heating Degree Days This Season: 821 -161 courtesy of the NWS
Average Temperature for this month So Far: 46.5 +1.8 courtesy of the NWS
Precipitation: Seasonal total for Fresno, 1.08, or -1.91, Month to Date: .80, or -.49
Precipitation for Bakersfield, Season, .40, +or- -1.29 Month to date .01, or -.74
Water year season is from October 1st through September 30.
Chilling Hours November 1st through February 28: Orange Cove, 473, Parlier, 562, Arvin, 448, Belridge, 524, Shafter, 513, Stratford, 536, Delano, 576, Porterville, 616
Hours at 45 or below 45. Courtesy UC Davis
Sunrise: 7:10 am Sunset: 4:50 pm Hours of Daylight: 9:39
Yesterday’s Weather
MCE : Merced 153 : DH1600 / 47 / 35 / 0.00 /
MAE : Madera 253 : DH1600 / 52 / 32 / 0.00 /
FAT : Fresno Airport 333 : DH1600 / 56 / 37 / 0.00 /
HJO : Hanford Airport 242 : DH1600 / 56 / 32 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1600 / 56 / 32 / 0.00 /
BFL : Bakersfield Airport 496 : DH1600 / 59 / 29 / 0.00 /
VIS : Visalia Airport 292 : DH1600 / 55 / 31 / 0.00 /
ATEC1 : Avenal 787 : DH1600 / M / 35 / 0.00 /
PTV : Porterville Airport 442 : DH1600 / 64 / 33 / 0.00 /
Rainfall: 24hr W.Y. % Last Y. % Ave. Year ave.
STOCKTON 0.00 1.70 41 4.16 100 4.18 14.06
MODESTO 0.00 1.45 41 3.19 90 3.56 13.11
MERCED 0.00 2.10 69 0.00 0 3.03 12.50
MADERA 0.00 0.69 21 0.00 0 3.24 12.02
FRESNO 0.00 1.08 36 0.00 0 2.99 11.50
HANFORD 0.00 0.49 19 0.00 0 2.53 10.10
BAKERSFIELD 0.00 0.40 24 0.00 0 1.69 6.47
BISHOP 0.00 0.01 1 1.10 80 1.37 5.18
SALINAS 0.00 0.83 24 4.32 126 3.42 12.83
PASO ROBLES 0.00 0.30 10 5.08 163 3.11 12.78
SANTA MARIA T 0.31 9 3.28 94 3.48 13.95
Next report: December 26/am