Every reporting weather station between Bakersfield to just south of Redding is reporting visibilities anywhere from 0 to ¼ of a mile. The weak trough of low pressure that moved through to our north yesterday evening has also lifted the fog deck higher into the atmosphere. T he fog now covers the lower foothills on each side of the valley. My feeling is, most locations, especially north of Kern County, will see little if any sunshine with high temperatures ranging in the 40s. in the past, I’ve seen fog regimes where the daytime highs and overnight lows were the same.
A strong winter storm is centered over Montana this morning and will shift into the northern Midwest later tonight. behind this system is a sharp ridge of upper level high pressure which extends from off shore California northward into Alaska. A blast of arctic air is now diving southward into the northern Rockies and will eventually engulf the eastern 2/3 of the U.S.
The flow loft over California is out of the northwest, so no chance of winter’s vengeance affecting central California. The main challenge through Christmas Eve will be temperature forecasting due to the fog and low clouds.
A weak upper low will approach the central and southern California coast Christmas Eve. Very little moisture is associated with this feature. It’s conceivable a sprinkle or two could fall somewhere. I’m banking on this system having enough cloud cover to hold temperatures up during the overnight hours.
Late Friday night and Saturday, a trough of low pressure will move into northern and central California. The upper air dynamics this far south will be weak, so any precipitation will likely be north of Kern County and even from Fresno County north, precipitation amounts will be rather scant.
The next chance of rain will arrive Sunday night and Monday. For the second day in a row, a rather robust low pressure system is shown centered just west of San Francisco Sunday night. It’s projected to more south/southeast through central and southern California Monday and Tuesday. One element we’ll have to watch late Sunday into Monday will be the possibility of strong, gusty winds in the south valley. On paper, sharp differences in paper show up between southern California and the northern California coast.
Looking farther ahead to the first week in January, models do show the possibility of active weather from time to time, so let’s keep our fingers crossed.
Forecast: Fog and low overcast through Christmas Eve with a chance of local afternoon clearing, mainly in Kern County. Highs will only warm into the mid 40s where no sunshine occurs and into the mid to upper 50s where the sun breaks through. Variable cloudiness above the fog Christmas Eve through Christmas Day with a slight chance of a few sprinkles. Increasing cloudiness Friday night with a chance of showers Saturday, mainly north of Kern County. A chance of a few showers Saturday evening, otherwise mostly cloudy Saturday night. increasing cloudiness again later Sunday with a chance of showers Sunday night. showers likely Monday and Monday night with a slight chance of showers Tuesday.
Short Term:
| Madera 47/40/47/41/52 | Reedley 48/39/47/40/51 | Dinuba 47/39/47/40/50 |
| Porterville 51/35/50/32/55 | Lindsay 50/34/50/32/55 | Delano 51/37/50/35/57 |
| Bakersfield 53/40/53/41/58 | Taft 57/45/58/45/60 | Arvin 57/33/58/35/60 |
| Lamont 53/37/53/39/60 | Pixley 48/39/48/41/52 | Tulare 46/39/47/41/48 |
| Woodlake 49/34/49/33/52 | Hanford 47/40/47/41/51 | Orosi 49/33/49/32/52 |
Seven Day Forecast:
| Christmas Day
Mostly cloudy 42/58 |
Saturday
Chance of showers 43/61 |
Sunday
Showers late 45/60 |
Monday
Rain likely 43/58 |
Tuesday
AM showers possible 38/55 |
Two Week Outlook: December 29 through January 4: This model is showing a pattern resulting in below average temperatures throughout much of the western U.S., including California. It also indicates below average precipitation, though some models do show a chance of precip during the period.
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 through Christmas Day will be generally less than 10 MPH late mornings and afternoons and at or less than 5 MPH during the night and early morning hours with extended periods of near calm conditions. I want to keep a close eye on the surface configuration for Sunday afternoon into early Monday. Currently they show a fairly strong difference in pressure between the high deserts and a surface low west of San Francisco. This could generate some strong, gusty, southeast winds in the south valley. It’s really too far out to nail it down but I felt it was worth mentioning.
Rain Discussion: It’s conceivable a sprinkle or two could occur Christmas Eve and Christmas Day with most locations remaining dry. There is a chance of light showers from Fresno County north after midnight Friday night. a chance of light showers will continue Saturday into Saturday evening, mainly north of Kern County. For now it appears most locations even north of Fresno will record no more than .10. dry weather will return for later Saturday night and Sunday. It looks like a rather robust system is projected by models to be just west of San Francisco Sunday night, tracking through central and southern California Monday and Monday night. this appears to be our best chance for a decent rain and snow event before the end of the year. Models for the first week in January at least show a chance of precipitation during that time frame.
Frost Discussion: It was 30 years ago today that the Great Freeze of 1990 began. It lasted for ten straight days. Widespred mid teenjs jto lower twenties were recorded during this period. Dave Carmen at the time recorded an historic low near Lindsay of 11.5 degrees.
No such numbers tonight. we now finally have a full fledged fog regime which now is thick enough to encompass the lower foothills regions. Most locations through Wednesday will not see the sunshine with highs in the 40s. clearing is possible, especially in Kern County, in which case readings would move into the 50s. with that classic wintertime low overcast, most readings will remain above freezing, but slightly above in those cold frost pockets.
Keep in mind, however, if for whatever reason the low clouds dissipate at any given locations, temperatures will easily rocket down to 27 to 29 or so. However, experience teaches me that tonight will be safe, as will Tuesday night and Wednesday morning.
A weak upper low will track through the southern half of California Christmas Eve and Christmas Day, hopefully throwing enough cloud cover over the valley to keep temperatures above freezing.
Higher clouds will begin to increase later Christmas Day into a chance of light showers later Saturday night through Sunday evening. The chance of rain will begin to increase Sunday night through Monday night as a more vigorous winter storm moves through. The air mass behind that system will be fairly cold. Hopefully we’ll get enough of a soaking to create a more conducive atmosphere for fog and low clouds to redevelop.
Air Quality Expectations: The San Joaquin Valley Air Pollution Control District has issued the following warning(s) for December 22, 2020:
The air quality for Merced County north is moderate. The air quality for the remainder of the growing area 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.
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, upper 30s to the lower 40s.
Actual Humidity Range Yesterday: Delano, 99%/60% Porterville, NA
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 0%, tomorrow 0%. Bakersfield: Today: 20% Tomorrow: 20%
ET Rates Over the Past Seven Days: Stratford .35, Parlier .30, Blackwell Corners .NA, Arvin .40, Orange Cove .30, Porterville .NA, Delano .31. Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 53, Parlier 50, Blackwell 55, Arvin, 51, Orange Cove 53, Porterville 51, Delano 45
Record Temperatures: 70/19. Average Temperatures: 54/35
Heating Degree Days This Season: 755 -164 courtesy of the NWS
Average Temperature for this month So Far: 47.0 +2.0 courtesy of the NWS
Precipitation: Seasonal total for Fresno, 1.08, or -1.70, Month to Date: .80, or -.28
Precipitation for Bakersfield, Season, .40, +or- -1.18 Month to date .01, or -.63
Water year season is from October 1st through September 30.
Chilling Hours November 1st through February 28: Orange Cove, 419, Parlier, 504, Arvin, 413, Belridge, 479, Shafter, 466, Stratford, 481, Delano, 518, Porterville, 558
Hours at 45 or below 45. Courtesy UC Davis
Sunrise: 7:09 am Sunset: 4:48 pm Hours of Daylight: 9:38
Yesterday’s Weather
MCE : Merced 153 : DH1600 / 44 / 36 / 0.00 /
MAE : Madera 253 : DH1600 / 45 / 38 / 0.00 /
FAT : Fresno Airport 333 : DH1600 / 52 / 35 / 0.00 /
HJO : Hanford Airport 242 : DH1600 / 49 / 34 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1600 / 49 / 28 / 0.00 /
BFL : Bakersfield Airport 496 : DH1600 / 60 / 33 / 0.00 /
VIS : Visalia Airport 292 : DH1600 / 53 / 31 / 0.00 /
PTV : Porterville Airport 442 : DH1600 / 60 / 30 / 0.00 /
LOSC1 : Los Banos 120 : DH1600 / 41 / 29 / 0.00 /
Rainfall: 24hr W.Y. % Last Y. % Ave. Year ave.
STOCKTON 0.00 1.70 43 4.11 104 3.94 14.06
MODESTO 0.00 1.45 44 2.80 84 3.33 13.11
MERCED 0.00 2.10 73 0.00 0 2.86 12.50
MADERA 0.00 0.69 23 0.00 0 3.04 12.02
FRESNO 0.00 1.08 39 0.00 0 2.78 11.50
HANFORD 0.00 0.49 21 0.00 0 2.33 10.10
BAKERSFIELD 0.00 0.40 25 0.00 0 1.58 6.47
BISHOP 0.00 0.01 1 1.06 83 1.27 5.18
SALINAS 0.00 0.83 26 4.22 131 3.21 12.83
PASO ROBLES 0.00 0.30 10 4.73 164 2.88 12.78
SANTA MARIA 0.00 0.31 10 2.72 84 3.24 13.95
Next report: December 22/pm