October 21, 2020
Summary: I’ll start this morning’s report with just a brief alert for early next week. It’s possible local frost may occur Tuesday and Wednesday mornings. I’ll detail that in the bottom portion of this summary.
Short term, we still have two high pressure systems at the upper levels of the atmosphere, the first of which is west of Baja with the second centered well off the northern California coast. A weak upper low is situated roughly 800 miles off the southern California coast. To our north, the northern branch of the jet stream is beginning to bend, allowing a large trough of low pressure to sag southward into the Pacific Northwest and eastward into the northern plains. This is slowly weakening the high over California and it will result in progressively cooler weather as we move through the remainder of the work week.
By Friday, this bend will sharpen, digging a trough southward into the interior west just to the east of the Sierra Nevada. Eventually it will move all the way southward into Arizona. My confidence level for Sunday and Monday’s outcomes is currently quite low as there are now models indicating the trough may dig southward further west and over California. For that reason, I need to add a small chance of showers to the forecast for Sunday into Monday. Even if it doesn’t rain on the valley floor, it will increase the chance of showers along the Sierra Nevada which could be a huge benefit to firefighters.
By Sunday night and Monday, a large high will be building just off shore and, with a cold trough of low pressure there will be a north/south flow digging into California. Couple that with a strong of shore wind event Sunday night into Tuesday and we could see mid to upper 30s Tuesday morning with a small chance of river bottom and similar locations teasing with the freezing mark. Could frost season already be right around the corner? By the latter part of next week, the high is projected by most models to be moving over California for a warming trend. But, at least, this long stretch of above average temperatures will come crashing down.
Forecast: Clear skies through Thursday night. mostly clear to occasionally partly cloudy Friday through Saturday. increasing cloudiness Saturday night. mostly cloudy Sunday through Monday morning with a small chance of scattered light showers. Clearing Monday afternoon. Mostly clear and chilly Monday night. mostly clear Tuesday through Wednesday.
Short Term:
| Madera 87/50/82/48/77 | Reedley 88/51/82/49/78 | Dinuba 87/50/82/48/76 |
| Porterville 88/52/82/49/78 | Lindsay 88/50/82/49/77 | Delano 88/53/82/51/78 |
| Bakersfield 88/62/83/58/78 | Taft 87/63/82/59/77 | Arvin 89/55/83/53/79 |
| Lamont 88/57/83/54/78 | Pixley 88/52/82/50/78 | Tulare 87/49/82/48/76 |
| Woodlake 87/50/82/48/77 | Hanford 88/51/83/49/78 | Orosi 86/50/82/47/77 |
Seven Day Forecast:
| Saturday
Partly cloudy 45/77 |
Sunday
PM showers 46/68 |
Monday
AM showers 42/73 |
Tuesday
Mostly clear 36/74 |
Wednesday
Mostly clear 39/75 |
Two Week Outlook: October 28 through November 3: This model flips us back into more of an amplified pattern with high pressure over the west and a colder trough east of the Rockies. Therefore, rain appears unlikely during this period with a return to above 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. Winds Saturday will be mainly out of the west or northwest at 8 to 15 MPH with stronger gusts. Winds will be out of the northwest Saturday night and Sunday at 10 to 20 MPH with stronger gusts.
Rain Discussion: Expect dry weather through Saturday night. later Sunday into Monday, we do need to add a small chance of light showers to the forecast. Most models still show the cold trough of low pressure digging southward into the Great Basin just to the east of the Sierra Nevada. However, a minority of models show this trough digging southward further west, putting it over California. Therefore, we need to add a minimal chance of light showers to the forecast for mainly Sunday afternoon into Monday morning. For Monday afternoon and beyond, look for dry conditions.
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 the entire growing region with the exception of Kern County. The air quality in Kern County is posted 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, 95%/32%, Porterville, 92%/26%
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 100%, tomorrow 100%. Bakersfield: Today: 100% Tomorrow: 100%
ET Rates Over the Past Seven Days: Stratford 1.06, Parlier .91, Blackwell Corners 1.01, Arvin 1.13, Orange Cove .99, Porterville .80, 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 66
Record Temperatures: 93/34. Average Temperatures: 77/48
Heating Degree Days This Season: 0, -45
Courtesy of the NWS
Average Temperature for September So Far: 72.1 +6.5
Precipitation: Seasonal total for Fresno, .00, -.32 Month to Date: .00, -.32
Precipitation for Bakersfield, Season, .00, +or- -.14. Month to date .00, -.14
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: 7:13 Sunset: 6:13 pm Hours of Daylight: 11:01
Yesterday’s Weather
MCE : Merced 153 : DH1700 / 90 / 51 / 0.00 /
MAE : Madera 253 : DH1700 / 88 / 51 / 0.00 /
FAT : Fresno Airport 333 : DH1700 / 88 / 60 / 0.00 /
HJO : Hanford Airport 242 : DH1700 / 89 / 50 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1700 / 90 / 52 / 0.00 /
BFL : Bakersfield Airport 496 : DH1700 / 89 / 62 / 0.00 /
VIS : Visalia Airport 292 : DH1700 / 88 / 55 / 0.00 /
ATEC1 : Avenal 787 : DH1652 / 87 / 59 / 0.00 /
PTV : Porterville Airport 442 : DH1700 / 88 / 55 / 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 0.40 14.06
MODESTO 0.00 0.00 0 0.00 0 0.36 13.11
MERCED 0.00 0.00 0 0.00 0 0.34 12.50
MADERA 0.00 0.00 0 0.00 0 0.36 12.02
FRESNO 0.00 0.00 0 0.00 0 0.32 11.50
HANFORD 0.00 0.00 0 0.00 0 0.21 10.10
BAKERSFIELD 0.00 0.00 0 0.00 0 0.14 6.47
BISHOP 0.00 0.00 0 0.00 0 0.18 5.18
SALINAS 0.00 T 0 0.00 0 0.31 12.83
PASO ROBLES 0.00 0.00 0 0.00 0 0.31 12.78
SANTA MARIA 0.00 0.00 0 0.00 0 0.28 13.95
Next report: October 22, 2020