December 20, 2019
Summary: Upper level high pressure located several hundred miles off the southern California coast is beginning to be suppressed southeastward by a developing trough of low pressure stretching from British Columbia southwestward to well out over the Pacific Ocean. Already overnight, high, thin clouds have overspread central California. Even with the high clouds, citrus frost stations were in the low to mid 30s.
The first phase of a major pattern change will begin tonight and Saturday as the first of possibly three weather systems approaches the northern California coast. Surface models indicate that from late Saturday afternoon into Sunday morning, sharp differences in pressure will develop between the approaching low and strong surface high pressure over the interior. By early Sunday morning, there will be roughly a 24 millibar difference in pressure between Salt Lake City and San Francisco. This will again create a squeeze play as winds increase and blow downslope off the Tehachapi Mountains and onto the Kern County portion of the valley floor. Winds in excess of 50 MPH will be possible from late Saturday afternoon through Sunday morning at places such as the bottom of the Grapevine with winds possibly exceeding 35 MPH as far north as Bakersfield. Gusty southeast winds are possible along the far east side of the valley during this time frame.
The chance for rain will begin to increase Sunday as a cold front moves through central California Sunday afternoon. The typical wintertime rain shadows will develop along the west side and over Kern County. Nevertheless, it’s possible as much as .25 to .33 may be measured, especially in Kern County.
It now appears there will be a short break Christmas Eve then, on Christmas Day, a colder storm will race southward, spreading showers over central California with lowering snow levels into the higher foothills, including the Kern County mountains. Showers should continue into Thursday.
Most of the models indicate the next low will move eastward as an inside slider, moving into the Pacific Northwest then into Nevada. Behind this system will be a chilly, north/northwest flow which could result in some cold overnight low temperatures, although nothing critical is foreseen at this time.
After the 27th, the storm track will move into the Pacific Northwest and occasionally northern California.
Forecast: a mix of high clouds and sunshine today. Variable high clouds tonight. increasing clouds Saturday. mostly cloudy Saturday night. periods of rain Sunday through Monday night. becoming partly cloudy Tuesday and Tuesday night. a chance of showers again Christmas Day and night. a chance of showers Thursday. Partly cloudy Thursday night and Friday.
Short Term:
| Madera 62/37/64/41/61 | Reedley 63/36/64/41/62 | Dinuba 61/35/63/40/61 | |
| Porterville 64/37/66/40/63 | Lindsay 63/35/64/40/63 | Delano 64/37/64/41/62 | |
| Bakersfield 65/45/70/47/67 | Taft 66/46/71/50/65 | Arvin 66/39/71/46/66 | |
| Lamont 65/40/71/48/65 | Pixley 64/37/64/41/63 | Tulare 61/35/63/41/61 | |
| Woodlake 63/35/64/40/62 | Hanford 63/38/64/42/62 | Orosi 63/35/64/40/61 | |
Seven Day Forecast:
| Monday
Periods of rain 41/55 |
Christmas Eve
Partly cloudy 37/53 |
Christmas Day
Showers likely 39/52 |
Thursday
Chance of showers 35/53 |
Friday
Partly cloudy 34/55 |
Two Week Outlook: December 27 through January 2: This model shows a cold weather pattern setting up with above average precipitation over southern California and the Desert Southwest. Temperatures under this regime will sink to below average values.
December: NOAA always projects warmer than average temperatures during the winter months and has a fairly low batting average. This model follows suit with a projection of above average temperatures, especially over the western U.S. The latest projection for precipitation is near average rainfall will prevail.
January, February, March: This model indicates above average temperatures this winter, but what’s new, especially over the western one-third of the U.S. There are two small notations for below average precipitation. The first is over Louisiana. The second is over northern and central California. Let’s hope this projection is inaccurate, but that’s the official prognosis from NOAA.
Winds: Winds today will be generally at or less than 7 MPH with periods of near calm conditions. After midnight tonight, winds will be generally out of the southeast at 5 to 10 MPH. Winds by later Saturday afternoon in Kern County will begin to increase out of the south to southeast at 15 to 25 MPH with stronger gusts. Winds Saturday night into Sunday morning in Kern County could exceed 50 MPH near the bottom of the Grapevine and locally elsewhere near the base of the Tehachapi Mountains. Winds possibly exceeding 35 MPH as far north as Bakersfield are possible. Saturday night and Sunday morning along the far west side, winds could gust to 40 MPH. Along the east side in Tulare, Fresno, and Madera Counties, winds will be out of the southeast at 10 to 20 MPH with local gusts to 30 MPH from Fresno County north. From Sunday afternoon through Monday, winds will be mainly out of the southeast at 10 to 20 MPH with stronger gusts. Winds Sunday night through Monday will be in the 10 to 15 MPH range with stronger gusts.
Rain: The chance for rain will begin to pick up Sunday morning. a cold front will move down the valley Sunday afternoon accompanied by widespread showers and continuing through Monday night. rainfall amounts from Sunday through Monday night will generally range from .15 to .35 in Madera County, eastern Fresno County, and Tulare County. Along the west side, .10 to possibly .25 is possible with less than .25 over the valley portion of Kern County. A brief break will occur Tuesday and Tuesday night, just in time for Santa, then a colder storm will bring widespread showers Christmas Day through Thursday with snow down into the higher foothills. After Thursday, the next system will drive into the Great Basin just to our east with only a slight chance of showers Thursday and Friday. It appears a couple of days of dry weather will commence before we possibly see more action towards the end of the year.
Frost Discussion: All locations will be above 32 degrees tonight, but possibly just slightly above in the coldest locations. Above freezing conditions will prevail Sunday through Thursday. It’s possible that, if we have a clear night during this period, lower 30s could occur, but even then mixing and wind conditions should help keep temperatures up.
There may be a dry slot after the 26th for a couple of days which, theoretically, could see temperatures at or just slightly below freezing. Models are having a difficult time nailing down a pattern between Christmas Day and New Year’s, but as of now, no classic freeze pattern is on the horizon.
Afternoon Dew Points Today: Upper 30s to the lower 40s. Kern: Mid to upper 30s. Humidity values ranging from 40%/80% at Hanford. Bakersfield 35%/65%
Actual Humidity range December 19, 2019: Delano, 95%/50% Porterville, 96%/40%
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 50%, tomorrow 0%. Bakersfield: Today: 60% Tomorrow: 20%
ET Rates Over the Past Seven Days: Stratford .39, Parlier .35, Blackwell Corner .38, Arvin .NA, Orange Cove .40, Porterville .32, Delano .35. Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 56, Parlier 52, Blackwell 55, Arvin, NA, Orange Cove 54, Porterville 52, Delano 48
Record Temperatures: 70/24. Average Temperatures: 54/35
Heating Degree Days this Season: 636 -241
Courtesy of the NWS
Average temperature for December so far: 51.5- +6.5
Precipitation: Seasonal total/average/above or below average:
Since Oct 1, 2018 Fresno: 2.50 season. or -.15. Month to Date: 1.78 +.83
Since Oct 1, 2018, Bakersfield: 1.61, or +.09. Month to Date: .53 -.04
Water year season is from October 1st through September.
Chilling Hours November 1st through February 28: Orange Cove 261, Parlier 333, Arvin 210, Shafter 251, Stratford 273, Delano 307, Lindcove 331, Porterville 489
Hours at 45 or below 45.
Sunrise: 7:08 Sunset: 4:46 pm. Hours of Daylight: 9:39
Yesterday’s Weather:
MAE : Madera 253 : DH1600 / 60 / 34 / 0.00 /
FAT : Fresno Airport 333 : DH1600 / 61 / 37 / 0.00 /
HJO : Hanford Airport 242 : DH1600 / 62 / 34 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1600 / 60 / 33 / 0.00 /
BFL : Bakersfield Airport 496 : DH1600 / 61 / 40 / 0.00 /
VIS : Visalia Airport 292 : DH1600 / 60 / 36 / 0.00 /
ATEC1 : Avenal 787 : DH1600 / 54 / 39 / 0.00 /
PTV : Porterville Airport 442 : DH1600 / 62 / 36 / 0.00 /
TFTC1 : Taft 759 : DH1552 / 59 / 42 / 0.00 /
LOSC1 : Los Banos 120 : DH1600 / 58 / 40 / 0.00 /
Rainfall: Water year Oct 1st through September 30th
24hr season % last year % Ave. 365 day ave.
STOCKTON T 4.11 109 5.00 132 3.78 14.06
MODESTO 0.00 2.80 88 4.20 132 3.18 13.11
MERCED 0.00 4.56 166 3.56 130 2.74 12.50
MADERA 0.00 1.91 66 2.85 98 2.91 12.02
FRESNO 0.00 2.50 94 2.27 86 2.65 11.50
HANFORD 0.00 1.77 81 1.80 83 2.18 10.10
BAKERSFIELD 0.00 1.60 106 1.20 79 1.51 6.47
BISHOP 0.00 1.06 87 1.31 107 1.22 5.18
SALINAS T 4.22 137 4.47 145 3.08 12.83
PASO ROBLES 0.00 4.73 173 3.52 129 2.73 12.78
SANTA MARIA 0.00 2.72 88 2.29 74 3.09 13.95
Next report: Friday afternoon/December 20