December 17, 2021
After getting literally soaked over the past several days, a very moist layer of shallow air had no problem condensing into fog and low clouds overnight. Infrared satellite imagery shows the entire San Joaquin Valley covered with the wintertime soup. Most locations still have a visibility of a mile or more. Bakersfield and Madera are each reporting a low overcast at 500 feet, Lemoore is reporting an 800 foot ceiling and Fresno 300 feet. Now that we’re nearing the winter solstice, we are into the shortest days of the year with the lowest sun angle, meaning the sunlight coming in is pretty weak, so some areas may not see sunshine at all while others may see a peak of hazy sunshine during the mid afternoon
At the surface, we have weak upper level high pressure centered over the Great Basin which is generating a weak off shore flow. At the upper levels o f the atmosphere, high pressure is centered off the southern California coast with a ridge building northward into the Pacific Northwest and northern California, creating a northerly flow aloft. The combination of fog and low clouds and a northerly flow aloft will create chilly conditions the next couple of days
Locations that receive little or no sunshine will remain in the 40s while locations receiving some hazy sun will warm into the lower 50s.
Medium range models beginning Monday show a cold low dropping out of the Gulf of Alaska to a position off the northern California/Oregon coast. Models show this feature parking there through the middle of next week. It will drop eastward late Wednesday and Thursday for another shot at some rain. That big low will remain off shore with impulses moving inland below the low, possibly creating a Christmas gift of prolonged rain
Forecast: Low clouds and fog through Monday. Clearing in some areas during the afternoon into hazy sunshine. Mostly clear to occasionally partly cloudy with areas of night and morning fog and low clouds Tuesday and Wednesday. Increasing clouds Wednesday night leading to a chance of rain Thursday and Christmas Eve.
Short Term:
Highs where the cold, gray overcast remains will rise into the upper 40s to near 50. Locations with hazy sunshine will see highs in the low to mid 50s. Overnight lows where fog and low clouds do not persist will lower into the upper 20s to mid 30s. overnight lows where overcast remains will be in the low to mid 40s through Monday
Seven Day Forecast:
Monday
Am fog/pm sun 33/52 |
Tuesday
Am fog/pm sun 33/51 |
Wednesday
Increasing clouds 36/55 |
Thursday
Chance of rain 42/57 |
Christmas Eve
Chance of rain 42/58 |
Two Week Outlook: December 24 through December 30: If this model holds water (no pun intended) the last week of 2021 will be a wet one. The flow aloft will become more westerly however, which means in spite of the rain, temperatures will be above average.
December, January, February: If this model is to be believed at all, temperatures will be marginally above average over central California. This model also depicts the main storm track continuing into the Pacific Northwest with somewhat below average precipitation over the southern 2/3 of California.
Wind Discussion: Winds today will be mainly out of the northwest at 8 to 15 MPH through this evening. Winds tonight through Monday will be generally at or less than 7 MPH with periods of near calm conditions.
Rain: Expect dry weather through at least Monday, and quite possibly Wednesday. Models are not in unison at all this morning, but it appears a cold low will drop southward from the Gulf of Alaska, parking far enough off the central coast for California to be rain free through Wednesday. The low will then move further south with energy moving into California beginning Thursday. we should see on and off rain Thursday through Sunday with the exception of the Sierra Nevada which will enjoy a very white Christmas. The two week outlook continue to show a wet pattern for the western 1/3 of the US right through the New Year.
Frost: One of the blessings of fog and low clouds is that they insulate the valley from below freezing temperatures. Twenty four hours ago, it seemed upper 20s and lower 30s were likely tonight. However, this low cloud deck covers the entire valley north to the lower Sacramento Valley, and with the winter solstice just a few days off, the fog will be tough to burn off. Bottom line is, if the fog remains locked in, above freezing conditions will prevail. The air mass above the valley floor is very cold, so locations that do clear out during the afternoon, upper 20s to lower 30s will be the likely overnight readings. As far as the individual numbers go for this report, I’ll call for temperatures to be above freezing in all locations with the possible exceptions of the cold frost pockets. However, this may change by this afternoon’s forecast as I want to watch the fog and low clouds to see if adjustments need to be made.
Actual Humidity Range Yesterday: Delano, 98%/48% Porterville, 100%/53%. Dew points: Upper 30s to the lower 40s. Kern: Mid to upper 30s.
Percentage of Sunshine Today/Tomorrow: Visalia: Today: 0%, tomorrow 60%. Bakersfield: Today: 0%/. Tomorrow, 40%.
ET Rates Over the Past Seven Days:. Stratford .31, Parlier .19, Arvin .32, Orange Cove .NA, Porterville .21, Delano .26. Courtesy University of California *=estimate, NA=not available.
Seven Day Soil Temperatures: Stratford, 56, Parlier 53, Arvin, .54, Orange Cove 54, Porterville 50, Delano 46 . *=data missing.
Average Temperatures: 55/37. Record Temperatures: 70/25
Heating Degree Days This Season. 648 -67 Varies widely from location to location. courtesy of the NWS
courtesy of the NWS
Precipitation: Seasonal total for Fresno, 3.27 +or +.1.11. Monthly .1.70. +.97
Precipitation for Bakersfield, Season, or 2.07 or +82. Month to date 1.12 or +.66
Average Temperature this month: 48.1 +.1.2 Taken NWS Hanford.
Water year season is from October 1st through September 30.
Chilling Hours November 1st through February 28: Orange Cove, 183, Parlier, 247 , Arvin, 246, Belridge, 265 , Shafter, 259 , Stratford, 275, Delano, 256 , Porterville, 286
Sunrise. 7:06, Sunset, 4:45, hours of daylight, 9:39
NA=missing
Yesterday’s Weather:
MCE : Merced AP 153 : 54 / 47 / 0.00 /
MAE : Madera AP 253 : 52 / 47 / 0.00 /
FAT : Fresno AP 333 : 51 / 45 / 0.00 /
HJO : Hanford AP 242 : 50 / 42 / 0.00 /
NLC : Lemoore NAS 234 : 53 / 41 / 0.00 /
BFL : Bakersfield AP 496 : 51 / M / 0.00 /
VIS : Visalia AP 292 : 51 / 41 / 0.00 /
PTV : Porterville AP 442 : 54 / 39 / 0.00 /
Rainfall: 24hr season % L.Y. % Ave. Annual total ave
STOCKTON M M M M M M 13.45
MODESTO M M M M M M 12.27
MERCED 0.80 3.52 145 1.91 79 2.43 11.80
MADERA M 0.93 44 0.55 26 2.12 10.79
FRESNO 1.03 3.27 156 1.07 51 2.10 10.99
HANFORD 0.87 2.48 157 0.49 31 1.58 8.13
BAKERSFIELD 0.90 2.00 165 0.40 33 1.21 6.36
BISHOP 1.35 2.62 301 0.01 1 0.87 4.84
SALINAS 1.25 4.97 179 0.66 24 2.77 12.58
PASO ROBLES M M M M M M 12.15
SANTA MARIA 1.13 3.53 145 0.30 12 2.43 13.32
Next report: December 17 PM