December 19, 2018
Summary: There was a potpourri of conditions out there this morning, ranging from a low overcast based at 3,500 feet at Kern and Tulare Counties to widespread ground fog elsewhere. The wide range in cloud conditions and fog resulted in a variety of overnight temperatures, from mid to upper 30s in portions of the west side to mid to upper 40s in Tulare and Kern Counties. Strong upper level high pressure is now entrenched off the southern California coast and has ridged northward into northern California. The freezing level is now all the way up to 13,400 feet, indicating a warm bubble of subsiding air is aloft. That, of course, spells inversion for the valley with widespread fog and/or low clouds through at least Thursday with clearing possible in some areas during the afternoons.
A weak ripple of low pressure will bring light showers to northern California Friday, but the impact on central California will be minimal. It may weaken the inversion as high pressure migrates southward into northern Baja. If it does, the fog and low clouds will lift and dissipate. If not, the low clouds and fog will continue.
Over the weekend, a zonal or westerly flow will develop across the eastern Pacific and into California with weak disturbances moving inland to our north from time to time. By late Sunday, a low pressure system will be dropping southeastward out of the Gulf of Alaska, possibly spreading light rain as far south as Fresno Christmas Eve afternoon with rain becoming likely Christmas Eve night and Christmas Day. Models aren’t quite as bullish about this being a significant weather event, but it will issue in a whole new weather pattern.
A second low will follow about 36 hours later and may form a low center over southern California with the possibility of light showers about the 27th and 28th. As this system begins to migrate eastward, a high oriented from southwest to northeast will build into the Pacific Northwest and possibly southern British Columbia. This would create a northerly flow up and down the west coast for the introduction of colder weather.
By New Year’s Day, the winds aloft will be north/northeast, possibly moving colder air with an overland trajectory over California. If this does occur, and there’s plenty of time for change between now and then, it would result in below freezing overnight lows. For now, it appears dry weather will prevail from the 28th through the first few days of 2019.
Forecast: Fog and/or low clouds this morning with partial clearing this afternoon. Widespread fog and/or low clouds tonight through Thursday with clearing possible in some areas Thursday afternoon. Low clouds Thursday night and Friday morning with areas of ground fog possible. Mostly cloudy Friday afternoon. Variable cloudiness at times Saturday through Sunday night with areas of night and morning fog. Increasing cloudiness Christmas Eve with a chance of light rain, mainly from Fresno County northward. Light precipitation will spread southward Christmas Eve night with periods of rain Christmas Day. A chance of showers Christmas night with a slight chance of showers Wednesday.
Short Term:
| Madera 56/38/56/38/56 | Reedley 57/40/55/42/56 | Dinuba 55/42/56/42/56 | |
| Porterville 55/42/57/39/57 | Lindsay 57/41/57/42/58 | Delano 57/43/58/43/58 | |
| Bakersfield 56/44/60/45/60 | Taft 61/45/63/46/63 | Arvin 56/43/62/42/63 | |
| Lamont 58/44/60/43/61 | Pixley 57/42/57/41/59 | Tulare 55/39/56/40/57 | |
| Woodlake 57/42/57/43/58 | Hanford 58/42/58/41/59 | Orosi 57/38/58/41/58 | |
Seven Day Forecast:
| Saturday
Areas of fog/mostly cloudy 43/57 |
Sunday
Areas of fog/mostly cloudy 40/57 |
Christmas Eve
PM showers possible 44/61 |
Christmas Day
Light rain likely 44/57 |
Wednesday
Slight chance of showers 37/52 |
Two Week Outlook: Christmas Day-December 31: This model is indicating a colder weather pattern will settle in over the western 2/3 of the U.S. It also indicates there’s an equal chance of dry and wet weather. Other models show generally dry weather between the 26 and January 1. Temperatures would be below seasonal average.
December: It’s been quite some time since this model has actually projected above average precipitation, but the good news is that is the case. It appears the dominant pattern for the month will maintain winds generally out of the west or northwest, which would favor above average temperatures.
December, January, February: It’s been a long time since the 90 day outlook projected above average precipitation for December through February, in other words the winter months. It also continues the better than even chance that over the next three months, temperatures will largely be above average. However, like any winter there will be below average periods as well.
Winds: Winds will be generally at or below 6 MPH through Saturday with periods of near calm conditions.
Rain: Expect dry weather through Sunday night. the first of two cold lows from the Gulf of Alaska could possibly spread light rain over the valley Christmas Eve afternoon, mainly from Fresno County north with periods of light rain spreading over the valley Christmas Eve night and Christmas Day. There is a slight chance of showers Christmas night. about 36 hours later, cold low number two will arrive. For now, I’ll just mention light showers with this event for late Wednesday into Thursday. At this point, the 29th through the first few days of the New Year look dry.
Frost Discussion: All locations will be above 32 degrees tonight and each night through at least Christmas morning. A colder shot of air will drive southward from the Gulf of Alaska, possibly bringing temperatures down to the low to mid 30s the day after Christmas. However, cloud cover may have something to say about this, keeping temperatures warmer than expected. A colder low will arrive later, possibly forming a new low over southern California. In the meantime, a southeast/northwest high will develop off shore, ridging into the Pacific Northwest and possibly the southern Canadian Rockies. If this scenario occurs, colder, drier air would feed in from the north, possibly taking an overland trajectory. If there’s any good news in this, it’s the fact that the high doesn’t look like it will ridge far enough to the northeast to pick up potentially colder air and, of course, this could change completely, alleviating a possible cold weather episode.
Afternoon Dew Points Today: Upper 40s to the lower 50s. Kern: Upper 40s to the lower 50s.
Humidity: Porterville: 80%/100%, Bakersfield: 70%/100%
Actual Humidity December 18, 2018: Delano, 99%/68% Porterville, 98%/65%
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 30%, tomorrow 20% Bakersfield: Today: 40% Tomorrow: 30%
ET Rates Over the Past Seven Days: Stratford .29, Parlier .28, Blackwell .35, Lindcove .25, Arvin .37, Orange Cove .30, Porterville .28, Delano .30 Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford 55, Parlier 52, Blackwell 54, Lindcove, 58, Arvin, 53, Orange Cove 54, Porterville 52, Delano 51
Record Temperatures: 74/25. Average Temperatures: 54/35
Heating Degree Days this Season: 599 -257
Courtesy of the NWS
Average temperature for December so far: 49.4 +4.4
Precipitation: Seasonal total/average/above or below average:
Since Oct 1, 2018 Fresno: 2.27 season. or -.32, Month to Date: .50 -.39
Since Oct 1, 2018, Bakersfield: 1.20, or -.27. Month to Date: .52 +.01
Water year season is from October 1st through September.
Chilling Hours November 1st through February 28: Orange Cove, 270, Parlier, 296 , Arvin, 228 Shafter, 313 Stratford, 270, Delano 288, Lindcove, 399, Porterville, 568
. Hours at 45 or below 45.
Sunrise: 7:07 am Sunset: 4:46 pm. Hours of Daylight: 9:40
Yesterday’s Weather:
MAE : Madera 253 : DH1600 / 64 / 40 / 0.00 /
FAT : Fresno Airport 333 : DH1600 / 60 / 47 / T /
HJO : Hanford Airport 242 : DH1600 / 62 / 42 / 0.00 /
NLC : Lemoore Naval AS 234 : DH1600 / 61 / 39 / 0.00 /
BFL : Bakersfield Airport 496 : DH1500 / 54 / 50 / 0.00
VIS : Visalia Airport 292 : DH1600 / 61 / 44 / 0.00 /
ATEC1 : Avenal 787 : DH1552 / 60 / 40 / 0.00 /
PTV : Porterville Airport 442 : DH1600 / 61 / 46 / 0.00 /
TFTC1 : Taft 759 : DH1554 / 56 / 47 / 0.00 /
LOSC1 : Los Banos 120 : DH1600 / 63 / 41 / 0.00 /
Rainfall: Water year Oct 1st through September 30th
24hr Season % L.Y. % Ave. Ave. yearly total
STOCKTON 0.00 5.00 135 0.91 25 3.70 14.06
MODESTO 0.00 4.20 135 0.98 32 3.11 13.11
MERCED 0.00 3.56 133 1.03 38 2.68 12.50
MADERA 0.00 2.85 100 0.32 11 2.85 12.02
FRESNO 0.00 2.27 88 0.37 14 2.59 11.50
HANFORD 0.00 1.80 85 0.37 18 2.11 10.10
BAKERSFIELD 0.00 1.20 82 0.03 2 1.47 6.47
BISHOP 0.00 1.31 110 0.16 13 1.19 5.18
SALINAS 0.00 4.47 149 0.75 25 3.01 12.83
PASO ROBLES 0.00 3.52 132 0.25 9 2.66 12.78
SANTA MARIA 0.00 2.29 76 0.09 3 3.02 13.95
Next report: Wednesday afternoon/December 19