December 19, 2021
There is still a lot of ground fog in the central San Joaquin northward into the southern Sacramento Valley. There is also a ribbon of fog extending southward towards the center of the valley into Kern County. Locations near the foothills to the east and west have largely cleared, creating a wide variance in the valley between the valley floor and the foothills. For example, Hanford was only 40 degrees at 1:00pm while Porterville was reporting 55. Even where the fog has cleared, there’s a narrow variance between temperatures and dew point, meaning fog will likely re-form in areas enjoying some sunshine.
In the big picture, satellite imagery shows a very large low pressure system about 700 miles west of the northern California coast. This system will be the central player this week as waves of low pressure will move towards the east/northeast into northern and central California beginning Tuesday. Models are having difficulty timing each impulse. Rain will spread over northern California Monday and into north/central California Tuesday. It will reach the remainder of the growing areas Tuesday night.
For the rest of the week and into the Christmas weekend, there will be periods of rain interspersed with periods of dry weather. Medium range models for the week between Christmas and New Year’s indicate a deep trough of low pressure extending from the Gulf of Alaska all the way into southern California with rain from time to time. The new two week model which goes out to January 2 still holds onto the idea of below average temperatures and above average rainfall.
Forecast: Widespread dense fog developing later tonight through Monday morning. Becoming partly cloudy Monday afternoon. Increasing cloudiness Monday night. Mostly cloudy Tuesday with a chance of rain in the afternoon from Fresno County north. Periods of rain Wednesday through Sunday throughout the region.
Short Term:
Madera 30/54/37/57 | Reedley 30/55/35/58 | Dinuba 29/53/36/57 |
Porterville 29/58/35/57 | Lindsay 28/54/34/58 | Delano 30/54/37/59 |
Bakersfield 35/58/39/60 | Taft 40/56/43/61 | Arvin 32/56/35/61 |
Lamont 32/54/37/60 | Pixley 30/54/35/58 | Tulare 29/53/35/58 |
Woodlake 29/54/35/58 | Hanford 30/54/35/57 | Orosi 29/54/34/57 |
Wind: Winds will be generally at or less than 5 MPH through Monday night with near calm conditions. Winds Tuesday will be out of the southeast at 8 ot 15 MPH with stronger gusts, especially from Fresno County northward. Winds Wednesday will continue out of the southeast at 10 to 20 MPH at times with stronger gusts.
Rain: The chance of rain will begin to increase Tuesday from Fresno County northward and over the remainder of the valley Tuesday night. Expect periods of rain Wednesday with on and off precipitation through the Christmas weekend. Models going out from Christmas to New Year’s also looks very unsettled, so the chance of rain at any given time will be relatively high. I also have to mention that this pattern will be a magnificent opportunity to build a strong snow pack over the high Sierra as this will be a prolonged event.
Frost: I’m going to stick with this morning’s number even though tonight’s forecast will be a difficult due to the nature of ground fog. Most of the citrus belt had cleared as of 1:00pm, however a narrow ribbon of fog remains up the center of the valley with widespread fog from Fresno northward to Redding. More often than not, when this occurs fog will spread southward with widespread fog throughout the valley by the evening hours. Currently, the spread between temperature and dew point is very narrow, suggesting that fog will form rapidly after sunset, inhibiting the radiational cooling process. I anticipate upper 20s and lower 30s. If the fog forms more rapidly and we end up with a warmer night, that’s’ all right with me. For Tuesday morning, a southeast flow up the valley will begin, helping to maintain above freezing conditions. We should also begin to see increasing clouds ahead of precipitation which will arrive in some parts of the valley as early as Tuesday afternoon.
Lows Tonight:
Terra Bella
29 |
Porterville
28 |
Ivanhoe
27 |
Woodlake
29 |
Strathmore
29 |
McFarland
27 |
Ducor
30 |
Tea Pot Dome
28 |
Lindsay
27 |
Exeter
28 |
Famoso
29 |
Madera
28 |
Belridge
27 |
Delano
29 |
North Bakersfield
29 |
Orosi
28 |
Orange Cove
28 |
Lindcove
27 |
Lindcove Hillside
33 |
Sanger River Bottom
26 |
Root Creek
27 |
Venice Hill
28 |
Rosedale
29 |
Jasmine
29 |
Arvin
31 |
Lamont
30 |
Plainview
28 |
Mettler
28 |
Edison
31 |
Maricopa
29 |
Holland Creek
30 |
Tivy Valley
27 |
Kite Road South
30 |
Kite Road North
27 |
AF=Above Freezing
Next report: December 20