December 21, 2019
Summary: Very strong surface pressure differences continue between the interior and an approaching low pressure system which, as of 6:30am, was centered just to the west of San Francisco. A cold front extends from the low just a few miles off the central coast. The following are peak wind gusts as of 6:30am: CHP office at the bottom of the Grapevine 58 MPH, the Grapevine CalTrans office 44 MPH, Mettler 39 MPH, Rancho Road 39 MPH, Oildale 31 MPH, west Bakersfield 32 MPH, Meadows Field 39 MPH, Coalinga 52 MPH, Digier Rd Hilltop at 5,100 feet in the Tehachapi Mountains…85 MPH. these winds will continue to be very strong this morning then die off in most areas by midday as the storm moves on shore and pressure gradients equalize.
Doppler radar is showing a swath of precipitation about 120 miles wide spreading over the Coast Range and into extreme western Fresno and Merced Counties. This precipitation shield will no doubt be reduced by a relatively dry air mass on the valley floor because of the strong winds. Even so, precipitation will move across the valley later this morning with periods of rain this afternoon through Monday. It’s possible showers could continue into early morning Tuesday. Most of Tuesday and Christmas Eve night will be dry then a very cold low originating in the far northeast Pacific will drop southward along the coast, resulting in more showers. The precipitation from this storm should be fairly light as the main dynamics around the low will remain just off shore.
Snow will fall down to 2,000 to 3,000 feet in the surrounding mountains, meaning some locally will have a white Christmas. And for those who don’t? Just take a short drive.
Showers will continue Thursday, tapering off Thursday evening. This low will then track across northern Baja and southern California Thursday night and early Friday then into the Desert Southwest over the weekend. This will allow a fairly strong ridge of upper level high pressure to build into the western U.S. this coming weekend and quite possibly through the end of the year. One model places another low off the southern California coast New Year’s Eve. The main challenge beginning Saturday will be below freezing temperatures and increasing amounts of night and morning fog and low clouds.
Forecast: Periods of rain later this morning and at times through Monday. Strong gusty winds will continue this morning in Kern County and along the far west side. A chance of showers Monday night into early Tuesday. Partly cloudy later Tuesday morning through Christmas Eve night. increasing cloudiness again Christmas morning with periods of showers Christmas afternoon through Thursday. A chance of showers Thursday evening, becoming mostly to partly cloudy late Thursday night and Friday morning. mostly clear to occasionally partly cloudy Friday afternoon through Sunday with increasing amounts of fog and low clouds.
Short Term:
| Madera 57/41/52/38/52 | Reedley 58/42/52/38/53 | Dinuba 57/41/51/37/51 | |
| Porterville 61/41/52/37/53 | Lindsay 60/41/52/37/52 | Delano 62/44/52/39/53 | |
| Bakersfield 66/47/52/43/53 | Taft 66/50/52/43/54 | Arvin 64/45/52/41/53 | |
| Lamont 66/46/52/43/53 | Pixley 63/44/52/40/53 | Tulare 57/41/52/38/52 | |
| Woodlake 58/41/52/37/52 | Hanford 58/42/52/38/53 | Orosi 58/40/52/37/52 | |
Seven Day Forecast:
| Christmas Day
PM showers 41/52 |
Thursday
Showers likely 40/52 |
Friday
Partly cloudy 35/51 |
Saturday
AM fog/pm sun 31/55 |
Sunday
AM fog/pm sun 30/54 |
Two Week Outlook: December 28 through January 3: This model indicates a dominant ridge of high pressure will be over the eastern Pacific and most of the western one-third of the western U.S. The chance of precipitation during this period is quite low with below average temperatures.
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 in Kern County through midday will continue to be out of the east to southeast at 15 to 35 MPH with gusts to near 60 MPH near the base of the Tehachapi Mountains and as high as 45 MPH as far north as Bakersfield. Localized gusty south to southeast winds are also possible along the Interstate 5 corridor. Elsewhere, north of Kern County winds will be mainly out of the east to southeast at 8 to 15 MPH with stronger gusts. Winds later this afternoon through Monday will be mainly out of the southeast at 8 to 15 MPH with stronger gusts. Winds Tuesday will be generally at or less than 12 MPH. Winds Tuesday night and Wednesday will be mainly out of the southeast at 8 to 15 MPH with stronger gusts.
Rain: The precipitation shield ahead of an incoming cold front has spread over the Coast Range and into western Fresno and Merced Counties, as of the time of this writing. The rain band is roughly 120 miles wide and will move across the valley later this morning followed by on and off periods of showers through Monday night. models still indicate that initially a rain shadow will be in place along the west side and over the valley portion of Kern County as strong south/southwest winds descend over the Kern County mountains and, to a lesser extent, over the Coast Range. Some models still indicate some fairly decent amounts of precipitation are possible, especially south of Fresno County, as the northern portion of this storm will affect the south valley as the low crosses southern California Monday. Therefore, rainfall amounts, possibly as much as .33, could be recorded over the valley portion of Kern County and .33 to .50 over Tulare County with about .33 in Fresno and Madera Counties.
A short dry slot will arrive Christmas Eve and Christmas Eve night through Christmas morning. then a colder low with origins in the northeast Pacific will move southward just off shore, spreading mainly light showers Wednesday afternoon through Thursday. The precipitation will turn to snow down to 2,000 to 3,000 feet, especially Thursday.
Dry weather will return Friday and should remain dry through the end of the year, although one model is showing a system off the central coast about New Year’s Eve. We’ll handle that later down the road.
Frost Discussion: All locations will be above freezing through Thursday morning. Low 30s are possible in colder locations Friday morning. the air mass behind the periodic storminess through Thursday is relatively cold as a north/northwest flow develops. Upper 20s and lower30s will certainly be possible beginning next Saturday morning and possible for several days thereafter, unless fog and low clouds take over which is certainly possible.
Afternoon Dew Points Today: Upper 40s to the lower 50s. Kern: Mid to upper 40s. Humidity values ranging from 55%/100% at Hanford. Bakersfield 25%/100%
Actual Humidity range December 21, 2019: Delano, 99%/46% Porterville, 99%/47%
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 0%, tomorrow 10%. Bakersfield: Today: 0% Tomorrow: 0%
ET Rates Over the Past Seven Days: Stratford .39, Parlier .36, Blackwell Corner .41, Arvin .NA, Orange Cove .40, Porterville .33, Delano .39. Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 55, Parlier 50, Blackwell 53, Arvin, NA, Orange Cove 52, Porterville 50, Delano 46
Record Temperatures: 70/19. Average Temperatures: 54/35
Heating Degree Days this Season: 667 -252
Courtesy of the NWS
Average temperature for December so far: 51.2- +6.4
Precipitation: Seasonal total/average/above or below average:
Since Oct 1, 2018 Fresno: 2.50 season. or -.28. Month to Date: 1.78 +.70
Since Oct 1, 2018, Bakersfield: 1.61, or +.02. Month to Date: .53 -.11
Water year season is from October 1st through September.
Chilling Hours November 1st through February 28: Orange Cove 277, Parlier 353, Arvin 236, Shafter 272, Stratford 293, Delano 329, Lindcove 354, Porterville 516
Hours at 45 or below 45.
Sunrise: 7:09 Sunset: 4:47 pm. Hours of Daylight: 9:39
Yesterday’s Weather:
MAE : Madera 253 : DH1600 / 62 / 46 / 0.00 /
FAT : Fresno Airport 333 : DH1600 / 63 / 45 / 0.00 /
HJO : Hanford Airport 242 : DH1600 / 65 / 39 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1600 / 64 / 39 / 0.00 /
BFL : Bakersfield Airport 496 : DH1600 / 72 / 43 / 0.00 /
VIS : Visalia Airport 292 : DH1600 / 67 / 41 / 0.00 /
ATEC1 : Avenal 787 : DHM / M / M / M /
PTV : Porterville Airport 442 : DH1600 / 68 / 39 / 0.00 /
TFTC1 : Taft 759 : DH1558 / 67 / 48 / 0.00 /
Rainfall: Water year Oct 1st through September 30th
24hr season % last year % Ave. 365 day ave.
STOCKTON 0.00 4.11 104 5.00 127 3.94 14.06
MODESTO 0.00 2.80 84 4.20 126 3.33 13.11
MERCED 0.00 4.56 159 3.56 124 2.86 12.50
MADERA 0.00 1.91 63 2.85 94 3.04 12.02
FRESNO 0.00 2.50 90 2.27 82 2.78 11.50
HANFORD 0.00 1.77 76 1.80 77 2.33 10.10
BAKERSFIELD 0.00 1.60 101 1.20 76 1.58 6.47
BISHOP 0.00 1.06 83 1.31 103 1.27 5.18
SALINAS 0.00 4.22 131 4.47 139 3.21 12.83
PASO ROBLES 0.00 4.73 164 3.52 122 2.88 12.78
SANTA MARIA 0.00 2.72 84 2.29 71 3.24 13.95
Next report: Monday morning/December 22