January 20, 2018
Summary: All of the upslope clouds which were along the Sierra Nevada foothills and the valley facing slopes of the Tehachapi Mountains dissipated during the early morning hours, allowing for strong radiational cooling, as expected. Just about all locations this morning are in the upper 20s to the lower 30s as of 6:30am. More in the frost discussion below.
Doppler radar is indicating rain is already spreading into northwest California and will reach the Bay Area late this afternoon. The parent low from this system is off the coast of British Columbia with the trailing cold front through western Washington and Oregon and the cold front extending southwestward off the northern California coast. This front will move through the valley tonight, but will rapidly weaken. As has been the case for much of January, the wet/dry line is inching further north, so it appears there will only be a small chance of light showers as far south as Fresno County.
Weak upper level high pressure will fill in behind the front, briefly, for dry weather Monday night through Wednesday. The next Pacific storm is stronger, but I did notice this morning that quantitative precipitation projections aren’t as strong as earlier noted. Fresno County northward may get a third to a quarter of an inch with lesser amounts further south.
Showers will continue Thursday, possibly into Thursday evening. Another relatively cold air mass will overspread the region. Temperatures by Friday, but more especially Saturday and Sunday, will dip well down into the 30s. more, again, in the frost discussion below.
Beginning next weekend, strong upper level high pressure will make its presence known with the storm track migrating much further north. This will set up an extended period of dry weather and typically upper level high pressure creates a warm air inversion which, in turn, is ideal for the development of fog and low clouds, possibly even extending through the afternoon hours.
The two week outlook suggests there’s a very low chance of rain with temperatures, at least in the foothills and coastal areas, well above average.
Forecast: Mostly clear this morning. High clouds will mix in this afternoon. Variable cloudiness tonight with a slight chance of light showers from Fresno County north, continuing Monday. Mostly cloudy Monday night and Tuesday morning. Becoming mostly clear Tuesday night and Wednesday morning. Increasing clouds Wednesday afternoon, leading to showers Wednesday night and Thursday with a chance of lingering showers Thursday afternoon. Partly to mostly cloudy Thursday night and Friday morning, clearing Friday afternoon. Mostly clear Friday night through Sunday with an increasing chance of fog and low clouds.
Short Term:
| Madera 55/36/56/38/58 | Reedley 56/35/57/39/58 | Dinuba 54/33/56/37/58 | |
| Porterville 56/34/57/38/59 | Lindsay 55/33/57/37/59 | Delano 56/36/53/39/58 | |
| Bakersfield 55/39/58/41/60 | Arvin 56/34/58/38/59 | Taft 57/39/58/42/59 | |
| Lamont 56/35/57/38/59 | Pixley 55/34/56/38/60 | Tulare 54/34/56/37/58 | |
| Woodlake 56/33/57/38/58 | Hanford 55/34/57/39/60 | Orosi 56/34/57/37/58 | |
Seven Day Forecast:
| Wednesday
PM rain 43/65 |
Thursday
Showers likely 44/56 |
Friday
Partly cloudy 34/53 |
Saturday
AM fog/PM sun 33/57 |
Sunday
AM fog/local clearing 37/58 |
Two Week Outlook: January 25 through January 31: This model now indicates a blocking ridge of upper level high pressure will be over and off the west coast. This pattern would drive the storm track well north. Temperatures would rise to marginally above average values, assuming the fog doesn’t take over, with very little chance of precipitation.
February: This model doesn’t really grasp at any particular pattern through the month. In fact, central California, if you believe this model, should have temperatures close to seasonal values with near average precipitation, as well.
February, March, April: This model goes all the way through April and it is calling for a ridge of upper level high pressure off the southern California coast to be the most dominant, but not the only, feature during the spring months. If this model has any credence at all, temperatures should be marginally above average with below average precipitation.
Winds: Winds will be generally less than 10 MPH with periods of near calm conditions through Wednesday.
Rain: The next Pacific storm is spreading rain into northern California at this hour. A rapidly moving cold front will move through central California tonight and early Monday. Latest model projections are backing off on the southern extremities of this storm, so I’m going with a dry forecast for regions south of Fresno County and even Madera and Fresno Counties will just have a minimal chance of light showers. Dry weather will return Monday night through Wednesday under a weak ridge. Periods of rain will spread down the valley Wednesday night through Thursday morning with a chance of showers through Thursday evening. Models have also backed off a bit on precipitation amounts. Current projections allow for perhaps a quarter to a third of an inch in Fresno and Madera Counties with considerably lesser amounts south of that line. Dry weather will return later Thursday night with the possible exception of upslope light showers in the extreme south valley. Dry weather will prevail Friday and last indefinitely as models show a persistent ridge of high pressure along the west coast.
Frost: The coldest reading I could find so far was 27 at Navalencia with a number of other locations, especially in Madera and Fresno Counties, down into the 28 to 29 degree range. Low 30s were dominant over much of Tulare and Kern Counties.
Tonight’s forecast will be somewhat tricky as currently clouds are advancing over northern California. The leading edge of the thicker cloud cover is approaching the Bay Area and will arrive in central California later this afternoon and tonight. For this forecast, I’m going to leave all areas above freezing because of the increase in cloud cover, but I encourage you to watch for the afternoon report as we tweak the forecast based on cloud observations to our north and northwest. If clouds, for whatever reason, are thin…we could see upper 20s to lower 30s. I’m not leaning that way currently, but weather always has be guessing.
The air mass that will filter in behind Monday’s system is not particularly cold so I anticipate above freezing conditions for Tuesday and Wednesday mornings. Above freezing conditions will also prevail Thursday. It’s possible low to mid 30s could occur Friday, but it will depend on the exit strategy of the cloud cover.
Upper 20s to mid 30s are possible Saturday through early next week as the air mass behind the Thursday event will be fairly cold, but certainly nothing to write home about. Strong upper level high pressure will take over this weekend and beyond for increasing amounts of fog and low clouds which no doubt will eventually be players in our temperatures.
Afternoon Dew Points Today: Low to mid 30s. Low to mid 30s.
Humidity: Visalia, 55%/90% Bakersfield, 45%.85%
Actual Humidity January 19, 2018: Delano, NA, Porterville, NA
Percentage of Sunshine Today/Tomorrow: Visalia: Today 70% tomorrow 20%, Bakersfield: Today 80% tomorrow 30%.
ET Rates Over the Past Seven Days January 19, 2018: Stratford .10, Parlier .NA, Blackwell, .29 Lindcove .21, Arvin .18, Orange Cove .26, Porterville .15, Delano .NA., Madera Two 14. Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 54, Parlier 53, Blackwell 56, Lindcove, 58, Arvin, 57, Orange Cove 51, Porterville 55, Delano NA, Madera Two 54
7.2
Record Temperatures: 72/24. Average Temperatures: 55/35
Heating Degree Days this Season: 1093, -428 Courtesy of the NWS
Average temperatures for January so far, 52.9 +8.4
Precipitation: Seasonal total/average/above or below average:
Since October 1, 2017 Fresno: 1.36 season. or -3.48. Month to Date: .95
Since October 1, 2017, Bakersfield: 1.03, or -1.64, Month to Date: .96
Water year season is from October 1st through September.
Chilling ours November 1st through February 28: Orange Cove, 548, Parlier, 583, Arvin, 549, Shafter, 645, Stratford, 590, Madera two, 971, Alpaugh, NA, Lindcove, 676, Porterville, 907. Hours at 45 or below 45.
Sunrise: 7:08 am Sunset: 5:13 pm. Hours of Daylight: 10:03
Yesterday’s Weather:
MAE : Madera 253 : DH1600 / 56 / 35 / 0.00 /
FAT : Fresno Airport 333 : DH1600 / 53 / 40 / 0.00 /
HJO : Hanford Airport 242 : DH1600 / 56 / 32 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1600 / 57 / 32 / 0.00 /
BFL : Bakersfield Airport 496 : DH1600 / 54 / 41 / 0.00 /
VIS : Visalia Airport 292 : DH1600 / 53 / 33 / 0.00 /
ATEC1 : Avenal 787 : DH1600 / M / 45 / 0.00 /
PTV : Porterville Airport 442 : DH1600 / 49 / 35 / 0.00 /
TFTC1 : Taft 759 : DH1555 / 53 / 43 / 0.00 /
Rainfall: Season % Last y. % Ave. Annual Ave.
STOCKTON 0.00 3.66 57 11.81 183 6.47 14.06
MODESTO 0.00 3.38 59 10.06 175 5.74 13.11
MERCED 0.00 2.16 39 9.56 174 5.48 12.50
MADERA 0.00 1.43 26 8.28 148 5.59 12.02
FRESNO 0.00 1.36 28 9.48 193 4.90 11.50
HANFORD 0.00 1.72 36 5.99 126 4.75 10.10
BAKERSFIELD 0.00 1.03 38 5.53 205 2.70 6.47
BISHOP T 0.20 8 4.37 182 2.40 5.18
SALINAS 0.00 2.22 40 8.65 155 5.57 12.83
PASO ROBLES 0.00 2.20 40 9.10 167 5.44 12.78
SANTA MARIA 0.00 1.97 34 9.79 169 5.80 13.95
Next Report: Sunday afternoon/January 21