January 19, 2019
Summary: Not a bad day out there as sunshine prevails this afternoon, in some cases shining through a thin layer of clouds. A weak ridge several hundred miles southwest of Los Angeles has built a temporary ridge northeastward into California. The high will rapidly give way Sunday morning as a trough of low pressure and its associated cold front move quickly down the valley late Sunday afternoon and Sunday night. Light rain could begin as early as late afternoon from Fresno north then spread rapidly southward during the night. the main emphasis with this system won’t be rain as precip amounts will be light, but wind which will be strong and gusty, especially along the cold front Sunday night into Monday morning. Gusts to around 35 MPH are possible along the front.
Upslope clouds will be banked up against the valley facing slopes of the Kern County mountains and, to a lesser extent, the west facing slopes of the Sierra Nevada. This may result portions of the eastern and southern San Joaquin Valley mostly cloudy through Tuesday morning. Those gusty winds will scour out the west side of the valley for clearing skies Monday.
Beginning Tuesday, a strong and large upper high will build over the eastern Pacific Ocean and the western one-third of the U.S. Once this occurs, the warm, subsiding nature of high pressure will create a warm air inversion for increasing amounts of night and morning fog beginning at midweek. Fog may become more extensive each day.
This appears to be a long lasting situation as models show the high remaining over and off the west coast through next week and well into the following week, as well.
Forecast: Mostly clear with high, thin clouds tonight with areas of fog and low clouds developing after midnight. Increasing cloudiness Sunday with light rain from Fresno north by late afternoon. Light rain will spread rapidly southward Sunday night, ending by the early morning hours. Mostly to partly cloudy and breezy Monday. Partly cloudy Monday night and Tuesday morning with patchy fog developing. Mostly clear Wednesday through Saturday with increasing amounts of night and morning fog, possibly locally persistent through the day.
Short Term:
| Madera 42/61/45/55 | Reedley 42/62/44/56 | Dinuba 41/61/44/55 | |
| Porterville 41/63/45/56 | Lindsay 41/63/45/55 | Delano 43/63/45/56 | |
| Bakersfield 46/64/46/56 | Taft 48/65/45/56 | Arvin 44/64/45/55 | |
| Lamont 44/65/45/56 | Pixley 42/63/44/56 | Tulare 42/62/45/55 | |
| Woodlake 41/61/44/55 | Hanford 42/62/45/54 | Orosi 41/61/43/56 | |
Winds: Winds will be generally less than 6 MPH with periods of near calm conditions into Sunday morning. Winds will be southeasterly at 5 to 15 MPH Sunday then, by late afternoon or evening, will be out of the northwest at 15 to 30 MPH with stronger gusts, possibly reaching 40 MPH along the west side. Winds Monday will be out of the northwest at 10 to 20 MPH, diminishing Monday night with winds becoming light later Monday night and Tuesday.
Rain: Rain, generally on the light side, will spread as far south as Fresno County, by late Sunday afternoon then will spread down the valley during the evening. This will be a fast mover so significant amounts are not expected. Most locations should pick up .10 to .20, possibly locally more in Fresno and Madera Counties. The rain should end by the early morning hours Sunday night with dry weather returning Monday. Look for dry weather to continue for the rest of next week and more than likely well into the following week, as well.
Frost Discussion: All locations will be above freezing both Sunday and Monday mornings. The air mass driving down from the north behind a cold front will move a cooler air mass into the region, but it’s by no means anything serious. Where skies clear Tuesday through Thursday mornings, low to mid 30s will be widespread with a chance of upper 20s in the coldest unprotected locations. Fog will become more and more prevalent midweek and beyond with slow moderation even without the fog.
Models this afternoon are still indicating arctic air moving southeastward will stay to the east of California later next week. For now, it appears upper level high pressure will ensure that air mass stays put.
Next report: Sunday morning/January 20