December 14, 2020
The low pressure system that brought significant precipitation to the central part of the valley and light amounts in the south valley has now moved into the Great Basin. It is being followed by the typical upslope clouds against the north facing slopes of the Kern County mountains and the valley facing slopes of the Sierra Nevada. Where it cleared overnight, areas of dense fog had no problem forming. That will be the main challenge for tonight and again Tuesday night as weak upper high pressure builds in from the west.
The air mass moving in from the northwest and wrapping around the back side of the low is colder. Coldest locations may dip to near freezing tonight with possibly more locations Wednesday morning, depending on fog and low cloud behavior. The freezing level taken a few hours ago above Oakland has now dropped down to 5,900 feet. The high will again back off shore Wednesday night. allowing the next Pacific storm to move through northern and central California late Wednesday night and Thursday. On paper, this looks to be similar both in potential and how far south precipitation will progress. It appears the Kern County mountains will again be the dividing line between dry weather over southern California and active weather over northern and central California.
Following this system, upper level high pressure will become reestablished over the eastern Pacific, driving the storm track back into the Pacific Northwest. With even more moisture on the valley floor, and a building warm air inversion over the valley this weekend, it’s possible we may see the beginning of our first true fog regime. It is possible the low clouds could persist through the day in some areas beginning Saturday.
Medium range models show a generally dry pattern from this weekend through the middle of next week.
Forecast: Areas of fog and low clouds this morning. mostly clear this afternoon. Areas of fog and low clouds developing later tonight, possibly becoming fairly widespread by morning with mostly clear skies Tuesday afternoon. Widespread fog and low clouds Wednesday morning then increasing higher clouds Wednesday afternoon. Showers will become likely late Wednesday night from Fresno County north and over the remainder of the valley Thursday. Mostly to partly cloudy Thursday night through Friday morning. mostly clear to occasionally partly cloudy Friday afternoon through Monday with increasing amounts of fog and low clouds, possibly persisting through the day in some areas.
Short Term:
| Madera 54/33/54/30/57 | Reedley 54/32/54/29/57 | Dinuba 53/32/54/28/56 |
| Porterville 53/33/54/30/56 | Lindsay 54/32/54/29/57 | Delano 54/34/54/30/58 |
| Bakersfield 52/38/55/35/59 | Taft 54/44/56/40/59 | Arvin 53/34/56/32/60 |
| Lamont 53/35/56/33/60 | Pixley 54/32/54/29/58 | Tulare 53/31/54/29/56 |
| Woodlake 54/32/54/29/58 | Hanford 55/34/54/30/57 | Orosi 53/32/54/29/56 |
Seven Day Forecast:
| Thursday
Showers likely 42/56 |
Friday
AM fog/partly cloudy 36/56 |
Saturday
AM fog/partial clearing 34/54 |
Sunday
AM fog/partial clearing 35/53 |
Monday
Am fog/partial cloudy 37/54 |
Two Week Outlook: December 20 through December 26: This model has central California on the dividing line between dry weather over southern California and potentially wet weather over northern California and the Pacific Northwest. I need to introduce a chance of showers from main Fresno north during this period with above average temperatures.
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 today will be mainly out of the northwest at 8 to 15 MPH with locally stronger gusts, diminishing later this evening. Winds tonight through Wednesday will be variable to no more than 10 MPH late mornings and afternoons and no more than 5 MPH during the night and early morning hours with extended periods of near calm conditions. Winds Thursday will be out of the northwest at 8 to 15 MPH with stronger gusts.
Rain Discussion: The following are rainfall totals as of6:30 this morning: Bakersfield .01, Mettler .08, Arvin .08, Taft .01, Porterville .08, Exeter .16, Tulare .15, Visalia .27, Hanford .22, Lemoore .24, Parlier .20, Fresno .50, Del Rey .30, Madera .07.
Dry weather can be expected through Wednesday evening. The chance of showers will increase again after midnight Wednesday from Fresno County northward and Thursday over the remainder of the valley. For now, this system appears to be similar to last night’s storm. The southern limit of precipitation will be across Kern County with heavier amounts further north. Dry weather will return Thursday night and will last through the weekend. If models are correct, dry weather will be with us through at least the middle of next week.
Frost Discussion: The air mass moving in behind last night’s storm system is colder. The freezing level over Oakland is down to 5,900 feet. The northwest flow behind this storm will continue to regenerate upslope clouds against the Tehachapi and the southern Sierra Nevada. These clouds may persist through Tuesday morning, mainly in Kern County and southeast Tulare County, but as usual there’s no guarantee. Fog and low clouds will have no problem forming tonight where skies are clear. The bottom line is, coldest low lying frost pockets could drop down to 27 to 28 with most flatland locations between 29 and 35.
Tonight’s conditions will be highly variable between locations.
The potential is there for more locations to drop to below freezing Wednesday morning. by then, a warm air inversion will be above the valley floor. Most models indicate widespread low 30s by Wednesday morning, however, in frost pockets where skies are clear and fog free, unprotected low spots could drop to 27 to 28 with most other locations from 28 to 33.
A new storm will arrive late Wednesday night with above freezing conditions both Thursday and Friday. Over the weekend, low 30s will be possible in the cold spots. I do look for widespread fog and low clouds this weekend and well into next week. It does appear conditions will be favorable for our first multi-day fog regime.
Lows Tonight:
| Terra Bella
Af |
Porterville
Af |
Ivanhoe
31 |
Woodlake
32 |
| Strathmore
Af |
McFarland
31` |
Ducor
Af |
Tea Pot Dome
32 |
| Lindsay
31 |
Exeter
32 |
Famoso
32 |
Madera
Af |
| Belridge
31 |
Delano
Af |
North Bakersfield
Af |
Orosi
30 |
| Orange Cove
32 |
Lindcove
32 |
Lindcove Hillside
Af |
Sanger River Bottom
28 |
| Root Creek
31 |
Venice Hill
Af |
Rosedale
Af |
Jasmine
Af |
| Arvin
Af |
Lamont
Af |
Plainview
32 |
Mettler
Af |
| Edison
Af |
Maricopa
Af |
Holland Creek
Af |
Tivy Valley
30 |
| Kite Road South
Af |
Kite Road North
30 |
AF=Above Freezing
Air Quality Expectations: The San Joaquin Valley Air Pollution Control District has issued the following warning(s) for December 14, 2020:
Today’s air quality is listed as moderate for Fresno, Kings, Tulare, and Kern Counties.. The air quality for the remainder of the valley is Good.
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 40s.
Actual Humidity Range Yesterday: Delano, 100%/58% Porterville, NA
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 50%, tomorrow 80%. Bakersfield: Today: 40% Tomorrow: 80%
ET Rates Over the Past Seven Days: Stratford .36, Parlier .32, Blackwell Corners .NA, Arvin .41, Orange Cove .32, Porterville .NA, Delano .33. Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 54, Parlier 50, Blackwell 55, Arvin, 52, Orange Cove 55, Porterville 51, Delano 44
Record Temperatures: 74/21. Average Temperatures: 55/35
Heating Degree Days This Season: 596, -155
Courtesy of the NWS
Average Temperature for this month So Far: 48.4 +3.0
Precipitation: Seasonal total for Fresno, 1.07, or -1.24, Month to Date: .79, or +.18
Precipitation for Bakersfield, Season, .39, +or- -.92. Month to date .T, or -.37
Water year season is from October 1st through September.
Chilling Hours November 1st through February 28: Orange Cove, 319, Parlier, 394, Arvin, 316, Belridge 371, Shafter, 351, Stratford, 363, , Delano, 400, Porterville, 450
Hours at 45 or below 45. Courtesy UC Davis
Sunrise: 7:05 am Sunset: 4:44 pm Hours of Daylight: 9:40
Yesterday’s Weather
MCE : Merced 153 : DH1600 / 53 / 47 / 0.11 /
MAE : Madera 253 : DH1600 / 55 / 40 / 0.05 /
FAT : Fresno Airport 333 : DH1528 / 51 / 47 / 0.19 /
HJO : Hanford Airport 242 : DH1500 / 50 / 40 / 0.22 /
NLC : Lemoore Naval AS 234 : DH1600 / 56 / 45 / 0.08 /
BFL : Bakersfield Airport 496 : DH1600 / 65 / 35 / 0.00 /
VIS : Visalia Airport 292 : DH1600 / 55 / 39 / 0.12 /
ATEC1 : Avenal 787 : DH1552 / 61 / 47 / 0.00 /
PTV : Porterville Airport 442 : DH1600 / 60 / 40 / T /
Rainfall: 24hr W.Y. % Last Y. % Ave. Year ave.
STOCKTON 0.54 1.09 33 4.01 120 3.34 14.06
MODESTO 0.43 1.12 40 2.79 100 2.78 13.11
MERCED 0.11 1.84 76 0.00 0 2.43 12.50
MADERA 0.05 0.54 21 0.00 0 2.55 12.02
FRESNO 0.22 0.84 36 0.00 0 2.31 11.50
HANFORD 0.22 0.49 26 0.00 0 1.85 10.10
BAKERSFIELD 0.00 0.39 30 0.00 0 1.31 6.47
BISHOP 0.01 0.01 1 1.06 98 1.08 5.18
SALINAS 0.11 0.64 24 4.09 151 2.71 12.83
PASO ROBLES 0.02 0.30 13 4.70 202 2.33 12.78
SANTA MARIA T 0.26 10 2.68 100 2.69 13.95
Next report: December 14/pm