November 6, 2020
Summary: Rapid changes are occurring over the western United States this morning. a fairly strong and quite cold low pressure system is off the California/Oregon border at this hour. Light showers have spread over roughly the northern one-fourth of California and will spread all over northern California by mid afternoon. As the low sinks into central California late tonight, light showers will spread over the valley possibly as early as early this evening. The center of circulation and its pool of cold, unstable air will be right overhead Saturday afternoon. Any breaks in the overcast allowing the sun to warm the ground will destabilize the atmosphere even more for the generation of scattered showers. Even an isolated thunderstorm or two tomorrow afternoon would not be a total shock.
Interestingly enough, most of the high resolution models this morning show the bulk of the showers moving southward along the western flank of the low. Showers will decrease for a time Saturday night. models over the last 48 hours have become more and more bullish on a cold low dropping southward from the Pacific Northwest and into northern and central California Sunday. This system is colder and, even though it’s taking an overland trajectory, models show a higher risk of showers with this system than the Saturday event. Showers will begin to taper off later Sunday evening as the low pulls off into the Desert Southwest.
By late Sunday night and Monday, a large upper high will be building off the central coast, creating a northerly flow aloft sandwiched between the off shore high and the storm to our southeast. This will drive colder and drier air into the valley, setting the stage for our first frost event Monday through Wednesday mornings. Of course, there’s more below in the frost discussion.
Another weak trough will move through about Wednesday, however most of the energy with this system is shown over the interior west. The bottom line is that the eastern Pacific high will remain off shore next week with a strong northwesterly flow aloft for much of the week. Models do show the chance of rain increasing for northern California with central California just south of the precipitation activity. Still, this pattern will continue below average temperatures with at least a chance of rain further down the road.
Forecast: Increasing cloudiness today and becoming breezy and much cooler. Scattered light showers tonight through Saturday with a slight chance of isolated thunderstorms Saturday afternoon. A small risk of light showers Saturday night. showers becoming likely Sunday into Sunday evening. Remaining mostly cloudy in Kern and Tulare Counties Saturday night with clearing skies elsewhere. Mostly clear to occasionally partly cloudy Monday through Friday with patchy night and morning fog.
Short Term:
| Madera 66/42/56/41/57 | Reedley 67/43/58/41/56 | Dinuba 66/42/57/42/56 |
| Porterville 68/43/58/42/56 | Lindsay 67/42/57/42/57 | Delano 69/44/58/43/57 |
| Bakersfield 70/48/56/45/56 | Taft 69/51/55/47/55 | Arvin 71/47/55/45/55 |
| Lamont 70/47/55/46/55 | Pixley 69/44/57/42/57 | Tulare 67/42/57/42/56 |
| Woodlake 68/42/57/41/56 | Hanford 68/45/58/44/57 | Orosi 67/41/58/52/55 |
Seven Day Forecast:
| Monday
AM clouds/PM sun 32/57 |
Tuesday
Patchy fog/partly cloudy 31/61 |
Wednesday
Patchy fog/partly cloudy 33/60 |
Thursday
Patchy fog/partly cloudy 35/62 |
Friday
Patchy fog/partly cloudy 37/61 |
Two Week Outlook: November 12 through November 18: This model continues to show the trend of below average temperatures over the western U.S. Even though there’s no strong signature for rain, rain is not ruled out, either, so the chance of precipitation remains low.
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: A dry cold front will push down the valley today. Behind the front, gusty winds out of the northwest at 15 to 25 MPH, mainly north of Kern County can be expected with local gusts to around 30 MPH expected this afternoon. Later tonight through Monday, winds will be mainly out of the northwest at 8 to 15 MPH with local gusts to 25 MPH, especially in the vicinity of showers.
Rain Discussion: Light showers will spread down central California tonight, continuing Saturday. interestingly enough, most of the models show the lion’s share of showers moving in just off the central coast. Even so, the center of circulation of a cold core low will be right overhead during the day Saturday, so daytime heating, especially if there are breaks in the overcast, should spawn scattered showers. I want to add the possibility of a thunderstorm or two Saturday afternoon. This first phase of a one-two winter punch will taper off Saturday night, however a more vigorous storm will drop southward from western Canada and into central California Sunday. The risk factor of showers is higher with this storm which will taper off Sunday evening with dry weather beginning later Sunday night.
Rainfall amounts from tonight through Sunday evening along the eastern flank of the valley north of Kern County should range between .l0 to .25. Potentially more could fall, especially if isolated thunderstorms develop. Over the valley portion of Kern County, .10 to .20 seems plausible. The west side will be affected by the typical winter storm rain shadow, so perhaps .10 to .15 could fall there.
For now, conditions Monday through Friday appear dry, however models do bring storminess back to northern California this weekend. At this point, central California will likely remain dry, but this is subject to change.
Frost Discussion: All locations will be above 32 degrees through Sunday morning. the second storm system to affect central California is a cold one and will drop freezing levels over central California to around 4,500 feet or so by Monday morning. typically, behind exiting winter storms the north/northwest flow will be lifted by the Kern County mountains, creating a bank of upslope clouds over Kern County and probably much of Tulare County as well. Clearing skies can be expected elsewhere. Where skies clear Monday morning, and winds are near calm, temperatures could drop to 28 to 29 degrees in typical cold spots and 30 to 33 degrees elsewhere.
Tuesday morning could be a bit colder on a more widespread basis with generally flat terrain dipping down to between 28 to 31 and unprotected cold spots down to 26 to 27 degrees. Slight moderation is expected Wednesday and more so Thursday and Friday.
Even though no rain is expected after this coming Sunday evening, the pattern will still be active so in and out cloud cover is expected through the week. It would be nice to get enough rain to put a decent amount of moisture in the soil which is always helpful with frost situations.
Air Quality Expectations: The San Joaquin Valley Air Pollution Control District has issued the following warning(s) for November 5, 2020:
Today’s air quality is listed as moderate for Merced, Madera, and Tulare Counties. The air quality for Kings and Kern Counties is deemed 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. Kern, Low to mid 50s
Actual Humidity Range Yesterday: Delano, 99%/38%, Porterville, 93%/32%
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 50%, tomorrow 20%. Bakersfield: Today: 50% Tomorrow: 10%
ET Rates Over the Past Seven Days: Stratford .77, Parlier .67, Blackwell Corners .76, Arvin .84, Orange Cove .78, Porterville .71, Delano .68. Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 63, Parlier 62, Blackwell 71, Arvin, 64, Orange Cove 67, Porterville 64, Delano 58
Record Temperatures: 87/33. Average Temperatures: 70/43
Heating Degree Days This Season: 53, -85
Courtesy of the NWS
Average Temperature for This Month So Far: 62.9 +5.9
Precipitation: Seasonal total for Fresno: .00, -.79 Month to Date: .00, -.16
Precipitation for Bakersfield, Season: .T, +or- -.39. Month to date .00, -.09
Water year season is from October 1st through September.
Chilling Hours November 1st through February 28: Orange Cove, 0, Parlier, 1, Arvin, 0,Shafter, Stratford, 0, Delano, 4, Lindcove, 0, Porterville, 8
Hours at 45 or below 45.
Sunrise: 6:28 am Sunset: 4:56 pm Hours of Daylight: 10:29
Yesterday’s Weather
mCE : Merced 153 : DH1600 / 78 / 41 / 0.00 /
MAE : Madera 253 : DH1600 / 77 / 43 / 0.00 /
FAT : Fresno Airport 333 : DH1600 / 76 / 51 / 0.00 /
HJO : Hanford Airport 242 : DH1600 / 77 / 43 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1600 / 78 / 43 / 0.00 /
BFL : Bakersfield Airport 496 : DHM / 73 / 52 / 0.00 /
VIS : Visalia Airport 292 : DH1600 / 76 / 47 / 0.00 /
ATEC1 : Avenal 787 : DH1600 / 77 / 50 / 0.00 /
PTV : Porterville Airport 442 : DH1600 / 76 / 48 / 0.00 /
LOSC1 : Los Banos 120 : DH1600 / 78 / 49 / 0.00 /
Rainfall: 24hr W.Y. % Last Y. % Ave. Year ave.
STOCKTON 0.00 0.00 0 0.00 0 1.07 14.06
MODESTO 0.00 0.00 0 0.00 0 0.88 13.11
MERCED 0.00 0.00 0 0.00 0 1.05 12.50
MADERA 0.00 0.00 0 0.00 0 1.11 12.02
FRESNO 0.00 0.00 0 0.00 0 0.79 11.50
HANFORD 0.00 0.00 0 0.00 0 0.73 10.10
BAKERSFIELD 0.00 T 0 0.00 0 0.39 6.47
BISHOP 0.00 T 0 0.00 0 0.37 5.18
SALINAS 0.00 T 0 0.00 0 0.75 12.83
PASO ROBLES 0.00 0.00 0 0.00 0 0.79 12.78
SANTA MARIA 0.00 0.00 0 0.00 0 0.78 13.95
Next report: November 6/pm