December 15, 2018
Summary: Generally clear skies prevail across the valley this afternoon with the exception of some high clouds which have spread as far southeast as Fresno County. Those high clouds are well in advance of a massive low which is centered west of British Columbia with its associated cold front moving into western Washington and, over the next few hours, northwest California. This system will be a fairly generous precipitation producer for northern California north of roughly a Monterey/Merced/Yosemite line. Unfortunately, the front will begin to lose much of its upper air support and dynamics as it marches through the valley Sunday night and Monday morning. Most, if not all, locations in the valley will pick up measurable rain, but mainly just light showers south of Fresno County.
The front will move into the Great Basin Monday afternoon and will be followed by what will become strong upper level high pressure off the southern California coast. It will be a wet week coming up over western Washington and Oregon, but the high will drive far enough to the north to begin an extended period of dry weather for most of California.
There will be a considerable amount of upslope clouds Tuesday against the west facing slopes of the Sierra Nevada and the north facing slopes of the Tehachapi Mountains, so clearing will be slow. Southeast Tulare County and Kern County will be the last to clear out. In all likelihood, the clearing over the valley floor will not last long as relatively high dew points and a developing warm air inversion create conditions ideal for Tule fog and low clouds.
After midweek, some areas may not see any sunshine while others may get an hour or two during the mid to late afternoon hours.
Above the inversion, at places like Oakhurst and Coarsegold, temperatures will top the 70 degree mark by midweek. Oh, and did I mention the gorgeous weather over on the coast?
A weak trough will move through the Pacific Northwest and northern California Friday night and Saturday, but it’s doubtful there will be enough impact to break up the inversion. A flat zone of high pressure will cover the eastern Pacific eastward into California for at least the first half of next week, maintaining a west to northwest flow. Models do not really change much until after Christmas. Believe it or not, that’s just a week from Tuesday! Some models still show the storm track trying to move further south for the chance of rain about the 27th but others show a dry regime continuing.
Forecast: Mostly clear before midnight. Partly cloudy after midnight through Sunday morning. Increasing cloudiness Sunday afternoon. Rain will spread southeastward, reaching Fresno County before midnight with light showers spreading into the south valley. Showers Monday morning with a chance of light showers Monday afternoon, mainly in Kern County. Mostly cloudy Monday night and Tuesday morning. Clearing Tuesday afternoon with the possible exception of Kern County and southeastern Tulare County. Mostly clear to occasionally partly cloudy Wednesday through Saturday but with extensive fog and/or low overcast with possible clearing in some areas during the afternoons.
Short Term:
| Madera 34/61/48/60 | Reedley 35/62/48/59 | Dinuba 33/61/47/58 | |
| Porterville 34/64/49/61 | Lindsay 32/62/47/61 | Delano 35/64/48/60 | |
| Bakersfield 40/65/50/62 | Taft 44/65/50/61 | Arvin 37/65/49/62 | |
| Lamont 38/65/49/62 | Pixley 34/63/48/60 | Tulare 32/60/47/58 | |
| Woodlake 32/62/47/59 | Hanford 35/63/49/60 | Orosi 32/61/48/59 | |
Winds: Winds will be generally 6 MPH with periods of near calm conditions tonight then will be mainly out of the southeast Sunday afternoon at 5 to 10 MPH, increasing to 5 to 15 MPH after midnight. Later Saturday, winds will be mainly out of the northwest at 5 to 15 MPH, becoming light and variable later Monday night and Tuesday.
Rain: Rain will become likely Sunday night, probably a bit before midnight as far south as Fresno County, breaking off into light showers over the remainder of the valley after midnight. Light rain will continue for a time over Fresno and Madera Counties with light showers continuing in the south valley, ending in most areas by noon Monday. There will be a small chance of a few showers mainly in Kern County, Monday afternoon, with dry weather returning Monday night.
I haven’t changed much on my thinking regarding rainfall amounts. Madera and Fresno Counties should receive .25 to .33, dropping off to .10 to .20 in Kings and Tulare Counties with .10 or less over the valley portion of Kern County. Monday night will be the beginning of a prolonged period of dry weather which will easily last through next week and more than likely through Christmas. Some models are trying to tug the storm line further south about the 27th. For now, though, I don’t hold too much stock in it.
Frost Discussion: Most, if not all, locations will be above freezing tonight. Tonight’s outcome will be mainly determined by higher clouds showing up after midnight. Already this afternoon there are some high, thin clouds over the northern part of the valley and off shore. However, cloud cover during the early morning hours may be too thin to keep temperatures different from last night’s.
For tonight’s package, the best way to go is to forecast the typical cold spots right at the freezing mark with just about every other locale above freezing.
Monday and Tuesday mornings will be above freezing due to heavy cloud cover and a milder air mass moving in aloft. Strong upper level high pressure will drive temperatures in the foothills up above the 70 degree mark, but anticipated fog and/or low clouds should blanket the valley as a warm air inversion develops, keeping temperatures above freezing during the overnight hours.
A couple of models are suggesting a north/northwest flow wrapping around an upper low over southern California. Theoretically, this would spread cooler and possibly drier air into the region, possibly leading to below freezing temperatures. Even these models don’t look alarming, though, so believe it not we may make it through the entire month of December with no real problems. I haven’t seen that occur for many a moon.
Lows Tonight:
| Terra Bella
32 |
Porterville
33 |
Ivanhoe
30 |
Woodlake
33 |
| Strathmore
32 |
McFarland
Af |
Ducor
Af |
Tea Pot Dome
33 |
| Lindsay
32 |
Exeter
32 |
Famoso
Af |
Madera
Af |
| Belridge
32 |
Delano
Af |
North Bakersfield
Af |
Orosi
32 |
| Orange Cove
33 |
Lindcove
31 |
Lindcove Hillside | Sanger River Bottom
30 |
| Root Creek
32 |
Venice Hill
33 |
Rosedale
Af |
Jasmine
33 |
| Arvin
Af |
Lamont
Af |
Plainview
33 |
Mettler
Af |
| Edison
Af |
Maricopa
Af |
Holland Creek
Af |
Tivy Valley
Af |
| Kite Road South
Af |
Kite Road North
Af |
AF=Above Freezing
Next report: Sunday morning/December 16