October 20, 2020
Summary: The overall pattern has only subtly changed over the past 24 hours. At the upper levels of the atmosphere, two high centers are apparent. One is off the Baja coast with the other roughly 700 miles off the northern California coast. Embedded within this large area of high pressure is a weak upper low located about 900 miles off the central coast. A trough of low pressure will begin to sag southward into the Pacific Northwest Wednesday, slowly increasing the onshore flow at the surface. The marine is currently about 1,400 feet deep and will deepen significant Thursday and Friday when this trough sags further south into the interior west.
Meanwhile, this will be drawing in the low currently well off the California coast eastward into southern California this weekend, but no active weather will be associated with this feature. From Saturday through Monday, a strong inside slider will move into Nevada and Utah, driving a dry cold front through central California Sunday and Monday. All of the models for the valley floor point to dry weather, however there may be enough lift for light rain and snow showers over the Sierra Nevada. Strong upsloping against the north facing slopes of the Tehachapi could wring out some drizzle or very light rain there.
The most radical change from Thursday on will be the triumphant beginning of autumn here in central California as the long awaited break from month after month of above average temperatures will occur this weekend. Some models show high temperatures down into the upper 60s Sunday and Monday. Overnight lows will finally begin to fall into the 40s on a widespread basis as early as Friday morning.
Just as soon as the cool weather exits, warmer weather will begin Tuesday as a massive high builds over the eastern Pacific and slowly encompasses all of the western U.S. by the middle of next week. There will be a strong off shore flow wind event Monday into Tuesday which will aid in the warming trend with readings returning to above average by a week from tomorrow.
Forecast: Mostly clear skies through Friday. Mostly clear to occasionally partly cloudy Friday night through Saturday. variable cloudiness Saturday night through Monday morning, much cooler and breezy. Clearing Monday afternoon. Mostly clear Monday night and Tuesday.
Short Term:
| Madera 88/51/87/50/81 | Reedley 88/52/87/51/82 | Dinuba 87/51/87/50/81 |
| Porterville 89/52/87/51/82 | Lindsay 88/51/87/50/82 | Delano 89/54/87/53/83 |
| Bakersfield 89/61/88/60/83 | Taft 87/64/87/61/82 | Arvin 90/55/88/53/83 |
| Lamont 89/55/87/54/83 | Pixley 89/53/82/53/81 | Tulare 87/51/86/49/80 |
| Woodlake 87/51/86/50/81 | Hanford 89/53/87/52/82 | Orosi 87/51/87/50/80 |
Seven Day Forecast:
| Friday
Mostly clear 47/80 |
Saturday
Partly cloudy 45/76 |
Sunday
Mostly cloudy 44/68 |
Monday
Partly cloudy 43/71 |
Tuesday
Mostly clear 42/78 |
Two Week Outlook: October 26 through November 1: This model indicates there will only be a low chance of precipitation for late October and early November. It also indicates near average temperatures.
October: This model essentially depicts the entire lower 48 with above average temperatures over the next 30 days. The most pronounced temperature anomalies will be over the Desert Southwest. This model also suggests there will be an equal chance of above or below average precipitation.
October, November, December: This model reflects the influence of La Nina. It paints above average temperatures over much of the country, especially the Desert southwest, and to a lesser extent, central California. Drier than average conditions are anticipated over southern California while northern California could possibly luck out with near average rainfall. Above average precipitation is expected over the Pacific Northwest.
Winds Discussion: Winds during the afternoon will be generally at or less than 10 MPH and variable through Friday. Winds during the night and morning hours will be generally less than 5 MPH with periods of near calm conditions.
Rain Discussion: There is a chance of light showers along the Sierra Nevada Sunday into Monday and possibly some drizzle or very light rain along the north facing slopes of the Tehachapi. However, there is no reason to add a chance of precipitation to the valley floor as all the models keep the main dynamics of this system in Nevada and Utah. If models are accurate, next Monday night and through the following week will be dry.
Air Quality Expectations: With the tremendous amount of smoke over the valley floor, it’s no surprise the San Joaquin Valley Air Pollution Control District has issued the following warning(s)s for October 20, 2020:
Today’s air quality is listed as moderate for Madera, Merced, and Kings Counties.
The air quality for the rest of the growing area is listed as unhealthy 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: Low to mid 50s. Upper 40s to the lower 50s.
Actual Humidity Range Yesterday: Delano, 81%/23%, Porterville, 89%/20%
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 100%, tomorrow 100%. Bakersfield: Today: 100% Tomorrow: 100%
ET Rates Over the Past Seven Days: Stratford 1.07, Parlier .92, Blackwell Corners 1.02, Arvin 1.14, Orange Cove 1.01, Porterville .81, Delano .90. Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 69, Parlier 71, Blackwell NA, Arvin, 71, Orange Cove 75, Porterville 73, Delano 67
Record Temperatures: 94/35. Average Temperatures: 78/49
Heating Degree Days This Season: 0, -41
Courtesy of the NWS
Average Temperature for September So Far: 72.3 +6.4
Precipitation: Seasonal total for Fresno, .00, -.29 Month to Date: .00, -.29
Precipitation for Bakersfield, Season, .00, +or- -.13. Month to date .00, -.13
Water year season is from October 1st through September.
Chilling Hours November 1st through February 28: Orange Cove, Parlier, Arvin, Shafter, Stratford, Delano, Lindcove, Porterville
Hours at 45 or below 45.
Sunrise: 7:12 Sunset: 6:14 pm Hours of Daylight: 11:03
Yesterday’s Weather
MCE : Merced 153 : DH1700 / 91 / 51 / 0.00 /
MAE : Madera 253 : DH1700 / 90 / 51 / 0.00 /
FAT : Fresno Airport 333 : DH1700 / 91 / 59 / 0.00 /
HJO : Hanford Airport 242 : DH1700 / 91 / 51 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1700 / 93 / 54 / 0.00 /
BFL : Bakersfield Airport 496 : DH1700 / 90 / 62 / 0.00 /
VIS : Visalia Airport 292 : DH1700 / 90 / 53 / 0.00 /
ATEC1 : Avenal 787 : DH1651 / 89 / 61 / 0.00 /
PTV : Porterville Airport 442 : DH1700 / 91 / 56 / 0.00 /
LOSC1 : Los Banos 120 : DH1600 / 88 / 60 / 0.00 /
Rainfall: 24hr W.Y. % Last Y. % Ave. Year ave.
STOCKTON 0.00 0.00 0 0.00 0 0.37 14.06
MODESTO 0.00 0.00 0 0.00 0 0.33 13.11
MERCED 0.00 0.00 0 0.00 0 0.31 12.50
MADERA 0.00 0.00 0 0.00 0 0.33 12.02
FRESNO 0.00 0.00 0 0.00 0 0.29 11.50
HANFORD 0.00 0.00 0 0.00 0 0.19 10.10
BAKERSFIELD 0.00 0.00 0 0.00 0 0.13 6.47
BISHOP 0.00 0.00 0 0.00 0 0.17 5.18
SALINAS 0.00 T 0 0.00 0 0.29 12.83
PASO ROBLES 0.00 0.00 0 0.00 0 0.29 12.78
SANTA MARIA 0.00 0.00 0 0.00 0 0.26 13.95
Next report: October 21, 2020