December 31, 2018
Summary: All the key ingredients are there for a hard freeze tonight through Thursday morning. Winds are screaming down the west side of the valley and through the Sacramento Valley. Winds are gusting to 37 MPH up at Gustine, 36 MPH at Panoche Road, and 29 MPH at Kettleman Hills. That’s as of 1:00pm.
The widespread low cloud deck is quickly vanishing. There is still some cloud cover along the north facing slopes of the Tehachapis, but I feel they will dissipate over the next few hours.
Skies will be generally clear tonight, leading to a strong radiational cooling event, driving temperatures into the mid to upper 20s in many areas and possibly colder than that in wind sheltered, low lying locations.
A strong relatively dry system is now moving into southern California and Arizona. Aloft, winds are wrapping around the back side of the low with a northeast flow aloft, which is all overland, and an air mass that originated in southern Canada. We are fortunate in one respect. The high didn’t build high enough to the north off shore to allow air from the arctic regions to move into California. Still, this will be a cold one and it will start the New Year off really busy. More in the frost discussion below.
The continuation through Wednesday of upper level high pressure ridging into western Canada will keep the strong northeast flow continuing until Wednesday morning with chilly days and very cold nights. It is our good fortunate to mention a flat zone of upper level high pressure will be draped across the eastern Pacific and into the western United States as early as Wednesday afternoon for the beginning of a warming trend Thursday, especially during the daytime hours. Once we head towards the weekend, the westerly flow will become southwesterly then a low pressure system currently out over the mid Pacific will move southeastward to a position off the northern Baja/southern California coast Sunday. This could result in heavy rain over portions of southern California with lighter amounts in central California.
Beyond Sunday and Monday of next week, models don’t show a definite pattern but they do show a possibility of rain about the 9th and 10th. For now, we’ll take it with a grain of salt.
Forecast: Mostly clear and cold tonight. Mostly clear and chilly New Year’s Day. Mostly clear and very cold Tuesday night through Thursday. Mostly clear to occasionally partly cloudy Thursday night through Saturday morning. Increasing cloudiness Saturday afternoon with a chance of rain later Saturday night and at times through Monday.
Short Term:
| Madera 26/51/24/53 | Reedley 27/52/24/53 | Dinuba 25/51/23/52 | |
| Porterville 26/50/24/53 | Lindsay 25/51/23/52 | Delano 27/51/25/53 | |
| Bakersfield 30/52/28/53 | Taft 35/51/29/53 | Arvin 27/51/25/53 | |
| Lamont 28/51/26/53 | Pixley 27/50/25/52 | Tulare 25/50/24/51 | |
| Woodlake 26/52/24/53 | Hanford 28/51/25/53 | Orosi 25/51/23/53 | |
Winds: Winds along the I-5 corridor will be out of the north at 15 to 30 MPH tonight with stronger gusts. Winds elsewhere will generally be in the 5 to 10 MPH range with periods of near calm conditions after midnight. Winds Tuesday and Tuesday night will be generally at or less than 8 MPH with periods of near calm conditions with possibly some strong, gusty northeast winds near the Interstate 5 corridor. Winds Wednesday through Thursday will be generally at or less than 8 MPH with extended periods of near calm conditions.
Rain: Dry conditions will continue through probably Saturday night. most of the models have pushed back the timing of a low pressure system approaching the northern Baja/southern California coast to Sunday and Monday. This could produce heavy amounts of rain in southern California with generally lighter amounts north of the Kern County mountains. Still, it’s the best chance of rain we’ve seen for a while.
Frost Discussion: All of the signatures are there for a couple of very cold nights coming up beginning tonight but more so Wednesday and Thursday mornings. Winds have been screaming down the west side where dew points have fallen into the mid to upper 20s. a strong northeasterly flow aloft is rapidly mixing out the solid cloud deck we had for a while this morning, so skies will be generally clear. Temperatures tonight may very well be quite chaotic due to wind conditions and very strong northeast winds above the valley floor.
Models for Porterville tonight show 29 on one model and 28 on another, which puts coldest locations in the mid 20s. wind conditions along the west side may very well keep temperatures above freezing in many areas tonight, however towards the central, southern, and eastern flanks of the valley, mixing may help in some areas but not others. Therefore, I’ll lean on the low side tonight and go with the potential threshold of this air mass.
The inversion tonight will be weak with temperatures at 34 feet generally being 2 to 5 degrees warmer.
On Wednesday morning, the wind factors will be greatly reduced and the full wrath of modified arctic air will be in its place. The potential for Wednesday and possibly Thursday mornings is regarding unprotected river bottom and like areas dropping down to 21 to 23 degrees with flat terrain type locations chilling down to 24 to 28. Coldest spots Wednesday morning may drop to freezing as early as 7:00pm and 28 degrees by midnight for long durations below 28. Once we get through this cold weather event, the westerlies will break in from the eastern Pacific as early as Wednesday night and will begin to impact temperatures by Friday morning.
Over the weekend, we should observe an increase in clouds from a storm system approaching the California coast. Temperatures will be held above freezing.
Lows Tonight:
| Terra Bella
27 |
Porterville
27 |
Ivanhoe
26 |
Woodlake
27 |
| Strathmore
26 |
McFarland
25 |
Ducor
28 |
Tea Pot Dome
26 |
| Lindsay
25 |
Exeter
25 |
Famoso
27 |
Madera
26 |
| Belridge
26 |
Delano
27 |
North Bakersfield
28 |
Orosi
25 |
| Orange Cove
26 |
Lindcove
25 |
Lindcove Hillside
30 |
Sanger River Bottom
23 |
| Root Creek
25 |
Venice Hill
26 |
Rosedale
27 |
Jasmine
26 |
| Arvin
27 |
Lamont
28 |
Plainview
27 |
Mettler
30 |
| Edison
28 |
Maricopa
26 |
Holland Creek
29 |
Tivy Valley
26 |
| Kite Road South
29 |
Kite Road North
26 |
AF=Above Freezing
Next report: Tuesday morning/January 1