December 28, 2020
The center of circulation of a cold core low pressure system is near Santa Maria this morning. it continues to pinwheel bands of showers inland, mainly over the southern half of the San Joaquin Valley. The freezing level, according to the balloon sounding over Oakland, dropped to 4,700 feet, down from nearly 10,000 feet about 24 hours ago. Models place the center of circulation over the Kern County mountains by midday, so periods of showers will be likely over the southern half of the valley well into the afternoon.
It appears the coldest and most unstable portion of the storm will be just to our south during the time of maximum daytime heating, so there’s only a slight risk of afternoon thunderstorms today. The low will track quickly through southern California and into the Desert Southwest Tuesday.
A zone of upper level high pressure will begin to push in from the west later tonight and Tuesday. The winds aloft between the incoming high and the exiting low will be out of the north, pushing a cold air mass into central California. Any location with clear skies, especially from Wednesday and beyond, will have no problem dipping below freezing. This is discussed in the frost section below. With additional moisture on the valley floor, fog and low clouds will develop in some areas nights and mornings, however the storm track will be just to our north which will have a tendency to mix out the warm air inversion from time to time. There are occasions, though, that even with a shaky inversion, fog and low clouds develop anyway.
The next weather system worth monitoring will arrive New Year’s Eve into New Year’s Day. Most models track this system through the Pacific Northwest then into the Great Basin as an inside slider. Some models, however, show it moving through northern and central California, resulting in a light chance of showers Thursday and New Year’s morning. for that reason, we’ll put a small chance of showers in the forecast during that time frame.
The first week in January will be very wet in the Pacific Northwest and northern California as a series of storms runs from west to east. A zone of high pressure will remain firm over central and southern California. However, with these stronger systems, precipitation may penetrate central California from time to time. For the second day in a row, the two week model is indicating above average precipitation during that time frame.
Forecast: Periods of showers today, mainly south of Fresno County. A chance of showers this afternoon, mainly south of Fresno County. Partly to mostly cloudy tonight and Tuesday morning. mostly clear to occasionally partly cloudy Tuesday afternoon through Wednesday night with periods of night and morning fog and low clouds. Variable cloudiness New Year’s Eve and Day with a slight chance of showers. Mostly clear to occasionally partly cloudy Friday night through Saturday night with areas of night and morning fog and low clouds. Increasing cloudiness Sunday, leading to a chance of showers by evening. A slight chance of showers Sunday night and Monday.
Short Term:
| Madera 55/34/53/29/52 | Reedley 56/34/53/28/51 | Dinuba 54/33/53/28/52 |
| Porterville 55/36/53/29/52 | Lindsay 54/34/52/27/51 | Delano 55/36/53/30/51 |
| Bakersfield 54/40/53/34/54 | Taft 53/42/53/40/53 | Arvin 53/39/53/33/54 |
| Lamont 53/39/53/33/52 | Pixley 55/33/53/28/51 | Tulare 54/34/53/27/51 |
| Woodlake 54/34/53/29/52 | Hanford 56/34/53/29/51 | Orosi 53/33/53/28/52 |
Seven Day Forecast:
| New Year’s Eve
Slight chance of showers 38/54 |
New Year’s Day
Slight chance of showers 39/53 |
Saturday
AM fog/partly cloudy 34/56 |
Sunday
Chance of showers 40/52 |
Monday
Chance of showers 41/57 |
Two Week Outlook: January 3 through January 9: This is the most encouraging two week model forecast I’ve seen for a while. It projects above average precipitation for all of California as the storm track migrates southward. Temperatures will be near to marginally below average.
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 this evening will be variable to 15 MPH with locally stronger gusts near showers. Winds tonight will be mainly out of the northwest at 5 to 12 MPH with locally stronger gusts. Winds Tuesday through Thursday will be generally at or 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.
Rain Discussion: Some fairly decent rainfall amounts have been recorded so far from the recent storm. Mettler .18, Taft .15, Bakersfield .26, Delano .14, Porterville .32, Exeter .27, Visalia .24, Hanford .14, Fresno .32, Orange Cove .32, Madera .07.
Periods of showers will continue this morning, mainly from Fresno County south, then will slowly end this afternoon from northwest to southeast. Rainfall amounts from this point on will generally be no more than a tenth or two with locally heavier amounts south of Fresno County. Since the pool of the most cold and unstable air is projected to be from the Kern County mountains south this afternoon, only a slight chance of thunderstorms exists this afternoon. Dry weather will return tonight.
The next chance of rain will be New Year’s Eve into New Year’s Day. Most models indicate this storm will be an inside slider with dry conditions. However, some show the storm slowing further south into northern and central California for a slight chance of showers. Expect dry weather Friday evening through Saturday night.
Beginning Sunday, the storm track is projected to slowly move southward with heavy precipitation over northern California with the rain line slowly moving into central California. The good news is there will be a chance of precipitation from time to time through the tenth of January interspersed with a couple of dry days between systems. This is an excellent pattern for the watersheds over northern California and possibly central California.
Frost Discussion: Most, if not all, locations will be above freezing tonight. However, where skies clear and winds settle down, readings from 30 to 32 are possible in frost pockets, mainly in Fresno, Madera, and Kings Counties. Upslope conditions should keep cloud cover over Tulare and Kern Counties. The air mass moving in behind today’s storm system is cold but nothing unusual for the time of year. Beginning Wednesday morning, any night with mostly clear skies and fog free conditions will have the potential to drop down to 27 to 28 degrees with even a small chance of mid 20s in unprotected frog ponds and other low spots. Most flatland locations will range between 28 and 32 with low to mid 30s in Kern County. Temperatures should inch up a bit Thursday and Friday due to cloud cover. Models show a storm moving into the Pacific Northwest then I not the Great Basin, but some models show the system moving more into northern and central California with even a chance of showers. During the second half of the weekend, the storm track will begin to sag southward with increasing clouds and above freezing conditions beginning Sunday and lasting for several days.
Lows Tonight:
| Terra Bell
Af |
Porterville
Af |
Ivanhoe
32 |
Woodlake
Af |
| Strathmore
Af |
McFarland
32 |
Ducor
Af |
Tea Pot Dome
Af |
| Lindsay
32 |
Exeter
31 |
Famoso
Af |
Madera
Af |
| Belridge
31 |
Delano
Af |
North Bakersfield
Af |
Orosi
32 |
| Orange Cove
32 |
Lindcove
Af |
Lindcove Hillside
Af |
Sanger River Bottom
30 |
| Root Creek
31 |
Venice Hill
Af |
Rosedale
Af |
Jasmine
Af |
| Arvin
Af |
Lamont
Af |
Plainview
Af |
Mettler
Af |
| Edison
Af |
Maricopa
Af |
Holland Creek
Af |
Tivy Valley
Af |
| Kite Road South
Af |
Kite Road North
Af |
AF=Above Freezing
Air Quality Expectations: The San Joaquin Valley Air Pollution Control District has issued the following warning(s) for December 28, 2020:
The air quality for is good for the entire growing region.
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: Mid to upper 40s. Mid to upper 40s
Actual Humidity Range Yesterday: Delano, 90%/55% Porterville, NA
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 10%, tomorrow 10%. Bakersfield: Today: 0% Tomorrow: 20%
ET Rates Over the Past Seven Days: THIS INORMATION IS UNAVALIABLE FOR MAINTAINENCE UNTIL FURTHER NOTICE. Stratford .24, Parlier .32, Blackwell Corners .NA, Arvin .40, Orange Cove .23, Porterville .NA, Delano .26. Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 52, Parlier 48, Blackwell 55, Arvin, 51, Orange Cove 51, Porterville 51, Delano 44
Record Temperatures: 66/24. Average Temperatures: 53/35
Heating Degree Days This Season: 866 courtesy of the NWS
Average Temperature for this month So Far: 46.9 +2.2 courtesy of the NWS
Precipitation: Seasonal total for Fresno, 1.14, or -2.05, Month to Date: .86, or -.63
Precipitation for Bakersfield, Season, .49, +or- -1.32 Month to date .10, or -.77
Water year season is from October 1st through September 30.
Chilling Hours November 1st through February 28: Orange Cove, 493, Parlier, 583, Arvin, 463, Belridge, 534, Shafter, 538, Stratford, 558, Delano, 601, Porterville, 652
Hours at 45 or below 45. Courtesy UC Davis
Sunrise: 7:11 am Sunset: 4:52 pm Hours of Daylight: 9:40
Yesterday’s Weather
MCE : Merced 153 : DH1600 / 57 / 37 / 0.00 /
MAE : Madera 253 : DH1600 / 59 / 39 / 0.00 /
FAT : Fresno Airport 333 : DH1600 / 59 / 42 / T /
HJO : Hanford Airport 242 : DH1600 / 60 / 39 / T /
NLC : Lemoore Naval AS 234 : DH1600 / 61 / 40 / 0.00 /
BFL : Bakersfield Airport 496 : DH1600 / 63 / 48 / 0.09 /
VIS : Visalia Airport 292 : DH1600 / 60 / 40 / T /
ATEC1 : Avenal 787 : DH1600 / 58 / 43 / 0.00 /
PTV : Porterville Airport 442 : DH1600 / 61 / 41 / 0.09 /
Rainfall: 24hr W.Y. % Last Y. % Ave. Year ave.
STOCKTON 0.00 1.83 41 4.19 95 4.42 14.06
MODESTO 0.00 1.50 40 3.22 85 3.78 13.11
MERCED 0.00 2.15 67 0.00 0 3.23 12.50
MADERA 0.00 0.70 20 0.00 0 3.45 12.02
FRESNO T 1.11 35 0.00 0 3.19 11.50
HANFORD T 0.51 18 0.00 0 2.78 10.10
BAKERSFIELD 0.09 0.49 27 0.00 0 1.81 6.47
BISHOP 0.00 0.01 1 1.10 75 1.47 5.18
SALINAS 0.00 0.85 23 4.76 131 3.63 12.83
PASO ROBLES 0.00 0.34 10 5.78 173 3.34 12.78
SANTA MARIA 0.00 0.31 8 3.86 104 3.72 13.95
Next report: December 28/pm