January 28, 2020
Summary: A large area of lower level clouds which had been covering the northern half of the San Joaquin Valley during the predawn hours is now advancing rapidly southward into the south valley. Above the low clouds is a layer of high clouds associated with a low pressure center moving through the Pacific Northwest. This system will dive southeastward and form a new low center over Utah and Arizona Wednesday. in the meantime, strong upper level high pressure over the eastern Pacific will ridge into Oregon and northern California. By Thursday, a surface high will be rapidly developing over the Great Basin. The combination of a northerly flow aloft and higher pressure over the interior will generate gusty north to northeast winds over the high Sierra and the Kern County mountains Wednesday through Thursday.
By Thursday night, and on through Saturday, upper level high pressure will be moving inland over California. In fact, some models place the center of circulation right over California Saturday. assuming the fog isn’t too widespread, temperatures could top the 70 degree mark Saturday and Sunday in the warmest locations.
Models continue to trend towards a major change in the overall pattern beginning late Sunday and Monday. For most of the winter, extremely cold air has been bottled up into Canada and Alaska, creating a mild winter for most of the lower 48. Fairbanks, Alaska will go through the month of January having never reached 5 degrees Fahrenheit. This is an all time record. Anyway, some of that cold air will finally dive southward into the interior western U.S. early next week. California will end up between a massive high off shore ridging up into Alaska and that trough just to the east of the Sierra Nevada.
There’s no question that a cold front will move through sometime Sunday night or Monday. It will be moisture starved with a chance of showers only over the Sierra Nevada and a very small chance over the valley floor. How much of this cold air spills into central California is still quite speculative due to model differences, but definitely temperatures will rocket down to at least marginally below average, if not more.
Forecast: Mostly cloudy this morning. mostly clear to occasionally partly cloudy this afternoon through Wednesday with areas of night and morning fog. Mostly clear Wednesday night through Saturday night with widespread night and morning fog. Increasing cloudiness late Sunday. Mostly cloudy Sunday night and Monday with a small chance of light showers. Partly cloudy, breezy, and cooler Monday night through Tuesday.
Short Term:
| Madera 59/39/56/37/60 | Reedley 59/38/56/37/61 | Dinuba 58/37/56/36/60 | |
| Porterville 59/38/56/38/62 | Lindsay 59/37/56/36/61 | Delano 59/40/56/38/62 | |
| Bakersfield 58/42/57/42/62 | Taft 58/45/56/44/61 | Arvin 58/40/56/38/62 | |
| Lamont 58/40/56/39/62 | Pixley 59/38/56/36/61 | Tulare 58/38/56/36/60 | |
| Woodlake 58/38/56/37/61 | Hanford 58/40/56/38/61 | Orosi 58/38/56/36/60 | |
Seven Day Forecast:
| Friday
Am fog/pm sun 39/65 |
Saturday
Am fog/pm sun 39/68 |
Sunday
Am fog/partly cloudy 41/67 |
Monday
Small chance of showers 38/55 |
Tuesday
Partly cloudy 32/55 |
Two Week Outlook: February 3 through February 9: This model indicates a large high will be off the north American continent with an equally large trough of low pressure over the interior west. This will result in a northerly flow with below average temperatures. The storm track is well north so precipitation is unlikely.
January: This model is rather inconclusive on precipitation and temperature trends. If anything, precipitation will be close to average with temperatures that are marginally above average. It does appear there will be potentially extended periods of dry weather, leading to episodes of fog and low clouds from time to time.
February, March, April: If this model has any kind of a grip on the situation, temperatures will run somewhat above average during the late winter/early spring period. This model would really dash the hopes of a wet winter as it does indicate below average rain for the three month period.
Winds Discussion: Winds will generally be at or less than 6 MPH with periods of near calm conditions through Friday.
Rain Discussion: Dry conditions will continue through Sunday. A major pattern change will drive a moisture starved cold front through the valley Sunday night and Monday. There’s a reasonably decent chance of showers over the Sierra Nevada and we’ll go ahead and add a minimal chance of light showers over the valley floor. After Monday, a massive area of high pressure will cover the eastern Pacific and eventually the Pacific Northwest and the western one-fourth of the USA.
Frost Discussion: Above freezing conditions will continue through Monday morning. a major pattern change will occur Sunday and Monday as modified arctic air will finally drop southward into the interior western U.S. A massive high pressure system will cover the eastern Pacific and will ridge upwards into Alaska. California will essentially be sandwiched between the massive high to our west and that cold trough east of the Sierra Nevada. It is a given that a cooler air mass will overspread central California. How much of that modified arctic air moves in from the north or spills over the Sierra is unclear, but for now at least local frost could begin as early as Tuesday morning, lasting for several mornings thereafter. I’ll continue to monitor this change closely in the coming days to see if a colder forecast is warranted.
Afternoon Dew Points Today: Mid to upper 40s. Kern: Mid to upper 40s. Humidity values ranging from 60%/100% at Hanford. Bakersfield 55%/100%
Actual Humidity range January 26, 2020: Delano, 100%/77% Porterville, 97%/68%
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 70%, tomorrow 70%. Bakersfield: Today: 50% Tomorrow: 70%
ET Rates Over the Past Seven Days: Stratford .39, Parlier .34, Blackwell Corner .35, Arvin .33, Orange Cove .32, Porterville .32, Delano .36. Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 52, Parlier 52, Blackwell 52, Arvin, 52, Orange Cove 52, Porterville 52, Delano 49
Record Temperatures: 70/25. Average Temperatures: 57/36
Heating Degree Days this Season: 1293 -361
Courtesy of the NWS
Average temperature for January so far: 47.7 +2.8
Precipitation: Seasonal total/average/above or below average:
Since Oct 1, 2019 Fresno: 3.53 season. or -1.76. Month to Date: .65 -1.17
Since Oct 1, 2019, Bakersfield: 2.83, or -.09. Month to Date: .23 -.72
Water year season is from October 1st through September.
Chilling Hours November 1st through February 28: Orange Cove 675, Parlier 745, Arvin 578, Shafter 658, Stratford 650, Delano 731, Lindcove 858, Porterville 1155
Hours at 45 or below 45.
Sunrise: 7:04 Sunset: 5:20 pm. Hours of Daylight: 10:14
Yesterday’s Weather:
MAE : Madera 253 : DH1600 / 64 / 49 / T /
FAT : Fresno Airport 333 : DH1600 / 64 / 50 / 0.01 /
HJO : Hanford Airport 242 : DH1600 / 67 / 48 / T /
NLC : Lemoore Naval AS 234 : DH1600 / 66 / 46 / 0.00 /
BFL : Bakersfield Airport 496 : DH1607 / 62 / 45 / 0.01 /
VIS : Visalia Airport 292 : DH1600 / 65 / 47 / T /
ATEC1 : Avenal 787 : DHM / 62 / 47 / 0.00 /
PTV : Porterville Airport 442 : DH1600 / 63 / 46 / T /
TFTC1 : Taft 759 : DH1551 / 62 / 48 / 0.00 /
Rainfall: Water year Oct 1st through September 30th
24hr season % last year % Ave. 365 day ave.
STOCKTON 0.10 5.27 75 7.91 113 7.00 14.06
MODESTO 0.06 3.92 63 6.35 102 6.25 13.11
MERCED 0.05 5.69 97 6.12 104 5.87 12.50
MADERA T 2.90 49 4.58 77 5.94 12.02
FRESNO 0.01 3.54 67 4.42 83 5.30 11.50
HANFORD T 3.12 62 3.33 67 5.00 10.10
BAKERSFIELD 0.01 2.83 97 2.27 78 2.92 6.47
BISHOP 0.00 1.16 45 3.46 136 2.55 5.18
SALINAS 0.11 5.99 99 5.80 96 6.07 12.83
PASO ROBLES T 6.61 111 6.36 107 5.96 12.78
SANTA MARIA T 4.79 76 6.41 101 6.32 13.95
Next report: January 28/afternoon