December 12, 2020
Summary: There is a combination of plenty of residual cloud cover and upslope clouds in Kern and Tulare Counties to result in a typically cool mid December afternoon. Temperatures are generally 3 to 5 degrees cooler then 24 hours ago and, as anticipated, dew points are up anywhere from 11 to 13 degrees. There will be just limited clearing tonight then clouds wil rapidly increase again from the west Sunday morning. the next trough of low pressure will rapidly move through central California Sunday afternoon through roughly midnight Sunday night.
The characteristics of this storm are quite similar to last night’s event with precipitation amounts probably ending up in that same ballpark, which is discussed in the summary below.
Monday through Wednesday will be dry as the eastern Pacific high which has been several hundred miles off shore the past few days will again move on shore. A warm air inversion will begin to develop above the valley floor Monday night through Wednesday and, yes, we are heading right smack into fog season. No doubt, we will see areas of dense fog and/or low clouds especially Tuesday and Wednesday mornings.
Some models seem to be trending back towards the next trough of low pressure to move through Thursday into Friday as that eastern Pacific high again retrogrades back towards the west. That will be our next chance of showers. The storm track is projected to become more zonal this coming weekend for another west to east flow with storm after storm soaking the Pacific Northwest and roughly the northern one-third of California from time to time.
There is a bleep I want you to pay attention to in the frost discussion below.
Forecast: Partly to mostly cloudy tonight with patchy fog developing after midnight. Increasing clouds Sunday morning. Showers becoming likely Sunday afternoon through roughly midnight Sunday night. mostly cloudy later Sunday night and Monday morning. partly cloudy Monday afternoon through Wednesday with areas of night and morning fog and low clouds. Increasing clouds Wednesday night leading to a chance of showers Thursday into Friday. Mostly to partly cloudy Friday afternoon through Saturday with areas of night and morning fog and/or low clouds.
Short Term:
Madera 39/57/40/53 | Reedley 40/57/40/54 | Dinuba 39/57/39/53 | |
Porterville 40/57/41/54 | Lindsay 39/58/41/53 | Delano 40/59/40/54 | |
Bakersfield 42/61/43/52 | Taft 45/60/46/53 | Arvin 42/61/43/52 | |
Lamont 41/60/43/52 | Pixley 40/57/40/54 | Tulare 39/56/40/53 | |
Woodlake 39/57/40/53 | Hanford 40/57/41/54 | Orosi 38/57/40/53 |
Winds: Winds through Sunday night will be mainly out of the northwest at around 5 to 12 MPH with locally stronger gusts, mainly in the vicinity of showers. Winds late Sunday night through Tuesday will be generally at or less than 10 MPH with periods of near calm conditions.
Rain: The next round of showers will begin from Fresno County north possibly as early as late Sunday morning, spreading down the valley during the afternoon. Most of the action should be over by roughly midnight Sunday, although some lingering showers near the foothills of Tulare and Kern Counties will be possible into Monday morning. rainfall amounts from this next system shouldn’t be far from last night’s event. With some luck, we could see .25 to .33 with locally more in eastern Fresno and Madera Counties and possibly as much as .25 from a Hanford/Tulare/Visalia line northward sloping to less than .10 over the valley portion of Kern County. Expect dry weather Monday through Wednesday night. some but not all models continue to trend towards a trough of low pressure moving through northern and central California Thursday into Friday. That will be our next chance of precipitation. This coming weekend, most models indicate a zonal or westerly flow will develop across the eastern Pacific and into the Pacific Northwest and roughly the northern 1/3 of California with precipitation possibly moving further south about the 22nd.
Frost: I’ll go ahead and discuss the long term outlook first. I’m not sure how many times in the quarter century I’ve been doing ag weather that we’ve observed above freezing conditions over the Christmas holiday, but they’re very few and far between. Just when medium range models were beginning to cooperate, at least one is showing a possible freeze pattern beginning around the 23 and lasting through the 26. Typically, a freeze pattern is when a massive high covers the eastern Pacific and builds a ridge into northern Canada while a low center develops either over the Desert Southwest or northern Mexico. Anyway, this creates a northeast flow aloft along with a strong off shore flow, both, theoretically, pumping cold dry air into the region. Since this is the first time this has shown up, at this point we’ll take it with a grain of salt, but we are heading into the time of year where even hints of trouble ahead need to be taken seriously I want to let you know that the record low for today’s date is 18 degrees. So, for now, we’ll watching the coming days to see if a trend develops or if this is an anomaly. Now, back to the present.
All locations will be above freezing Sunday and Monday mornings. Low to mid 30s appear likely Tuesday and Wednesday with a slight chance of upper 20s in those pesky frost pockets. However, with considerable amounts of moisture now available on the valley floor and a warm air inversion developing Monday night through Wednesday, our brothers in arms—fog and low clouds—-have become more of a factor. We should see increasing cloudiness Thursday through Friday for above freezing conditions and a mild westerly flow Friday night through a week from Monday.
Next update: December 13/am