December 13, 2021pm
It’s a rare day to observe visible satellite imagery. There is a significant rain shadow across the central and south valley. If you look at the cloud patterns from above, you see wave clouds which are indicative of powerful winds aloft. Most locations on the valley floor have recorded less than .10 of an inch while over on the coast, Big Sur has recorded almost 3 inches, Three Peaks 2.41, Pacifica 4.15, and Half Moon Bay 3.62. As they say, dynamics come into play.
The main stream of moisture continues to our north and will move through tonight and Tuesday, especially during the morning. There remains potential for heavy rain on the valley floor if there is enough moisture to overcome the rain shadow. What’s coming into focus, though, is that the valley floor will not pick up 2 inches of rain.
The backside of the main area of low pressure will move through Oregon and northern and central California late tonight and early Tuesday morning. The rain will turn to scattered showers later Tuesday afternoon and dry weather returning Tuesday night and Wednesday.
A weaker low will move out of the Gulf of Alaska and into California Thursday and Thursday night. This system is colder and does not carry nearly as much moisture as the current storm. By Friday, upper level high pressure will be situated over the eastern Pacific with a ridge building eastward into the Pacific Northwest. This will set up a northeast flow aloft. The air mass associated with this system is quite cold with temperatures on the valley floor likely not reaching the 50 degree mark Tuesday through Thursday.
The high will ensure dry weather this weekend. Nothing ominous shows up until about the 22 when some models show a pattern developing similar to the current one.
Forecast: Rain at times tonight and Tuesday morning, turning to showers Tuesday afternoon with a slight chance of thunderstorms. A chance of scattered showers Tuesdays night. Mostly to partly cloudy Wednesday. Increasing cloudiness Wednesday night. Light showers will be likely Thursday and Thursday night. Mostly to partly cloudy Friday. Mostly clear to occasionally partly cloudy Friday night through Tuesday with areas of night and morning fog and low clouds.
Short Term:
| Madera 46/51/32/48 | Reedley 49/51/33/48 | Dinuba 47/50/42/48 |
| Porterville 46/51/33/48 | Lindsay 46/52/32/48 | Delano 47/50/32/48 |
| Bakersfield 49/51/38/47 | Taft 46/50/36/44 | Arvin 47/52/38/46 |
| Lamont 49/53/39/46 | Pixley 46/51/33/48 | Tulare 45/50/32/48 |
| Woodlake 46/51/33/48 | Hanford 46/52/34/47 | Orosi 45/51/32/47 |
Wind: Winds have gusted to 52 mph at Stockton, 48 mph at Merced, sloping to 29 at Madera. So far, winds have been reasonably light south of Madera. These winds have not yet reached the central or south valley but may as the evening progresses. For tonight, expect winds mainly out of the southeast at 15 to 25 MPH along the west side and 10 to 15 mph elsewhere. Wind gusts to near 40 mph are possible in Kern County near the base of the Tehachapi Mountains. Winds will be out of the northwest at 10 to 20 mph later Tuesday, diminishing Tuesday evening with generally light winds Wednesday. Winds Wednesday night and Thursday will be mainly out of the northwest at 10 to 15 mph at times.
Rain: Here are a few rainfall amounts for the valley as of 1:00pm. Fresno .09, Bakersfied .01, Exeter .02, Lemoore .08, and Huron .02.
The first part of this event has been a dry one for the valley south of Merced. The main rain shield is still to the north and west and will move through tonight and Tuesday morning. Rainfall amounts from this point on will generally range from .50 to 1 inch north of Kern County on the east side of the valley, .25 to .33 along the western side of Fresno and Kings Counties. That rain shadow is literally robbing Kern County. Expect between .10 and .25 to accumulate there. Showers will come to an end Tuesday evening with a short period of dry weather from Tuesday night through Wednesday night. Showers will spread down the valley again Thursday and Thursday night with dry weather Friday and into next week.
Frost: All locations will be above 32 degrees tonight. A very chilly air mass will overspread the valley tonight and Tuesday. High temperatures will not get out of the 40s, especially beginning Thursday after this next system goes through. Overnight low temperatures any night from Wednesday night/Thursday morning could drop into the low to mid 30s. most of that will be contingent on the amount of cloud cover we have. Models are showing a decent cloud deck over the valley floor Thursday into Friday. From Saturday through Monday most locations will remain above freezing. Keep in mind, though, that any night with mostly clear skies will have readings below that level.
Next report: December 14