Projected rainfall totals for Mariposa: 0.25" to 0.50"
Projected rainfall totals for Oakhurst: 0.25" to 0.50"
Projected rainfall totals for Yosemite Valley: 0.10" to 0.25"
January 22, 2021 - The National Weather Service Hanford Office reports a storm system will pass through the Golden State this afternoon into Saturday, resulting in precipitation throughout most of Central California.
The majority of this precipitation will fall this afternoon and tonight.
Snow levels could drop as low as 3,000 feet tonight.
An inch or less of snow is conceivable over Kern County mountain passes tonight and Saturday, resulting in the possibility of travel delays.
Area Forecast Discussion National Weather Service Hanford CA 309 AM PST Fri Jan 22 2021 .SYNOPSIS...A series of storm systems will bring episodes of rain and mountain snow to the central California interior starting today. This unsettled pattern will last through at least the middle of next week along with significantly cooler temperatures. && .DISCUSSION...Water vapor satellite imagery show mid-level and high clouds in the southwest flow aloft over Central California, ahead of the upper-level low just off the coast of far northwestern CA. The associated trough continues to dig southward along the Northern CA coast and towards the SF Bay Area. So, today`s storm, or the first in the series of at least three storm systems, will soon arrive. Precipitation chances begin later this morning towards our northern portions and by this afternoon to the south, including Kern County. This system will bring mainly light precipitation to the region, or up to 0.10 to 0.25 inch of precipitation in the San Joaquin Valley and Sierra Nevada foothills and around 0.25 to 0.50 inch in the Sierra Nevada. About 2-4 inches of snow is likely in the Sierra above 4,000 feet, although isolated slightly higher amounts are possible. Snow levels will be generally around 4,000 over the mountain areas, though remain a bit higher in Kern County until this afternoon. However, by this evening snow is possible at the pass levels, including near the Grapevine, although it will likely be a dusting and up to 1-2 inches in the higher elevations elsewhere in the Kern County mountains. In addition, southwest winds may pick up this afternoon in the Kern County mountains and desert, with local gusts around 45 mph possible. In addition, with the passage of the upper-level trough, some rather cold air aloft could provide instability this afternoon, so an isolated thunderstorm or two cannot be ruled out. Otherwise, cooler temperatures will be in store for today and some time to come. Expect mainly seasonal temperatures for today and Saturday, with cooler than normal temperatures by early next week. A break between systems is expected on Saturday evening through Sunday morning. The next system will arrive by Sunday afternoon and bring precipitation to our forecast area into Monday. Precipitation amounts are projected to be a little higher with this second system, with 0.20 to 0.40 inch possible in the Central Valley and 0.50 to 0.75 inch in the Sierra Nevada, although the mountain precipitation is expected to be mainly in the form of snow. This storm will be quite cold, and snow will likely fall at elevations down to around 1,500 feet and possibly a little lower. Just about anywhere at and above these elevations could report at least some flurries or light snow, so travel may be impacted with possible delays. Snow and rain amounts remain a bit uncertain with medium confidence at best for this particular system. However, as we get closer, winter weather statements may become necessary for areas in the Sierra Nevada, adjacent foothills, and Kern County mountains. Even some areas in the Kern County desert could observe flurries or light snow. On Tuesday, a break in precipitation is likely across the region. There is the possibility of impactful precipitation on Wednesday into Thursday with the next storm, or storm number three. Snow levels rise to around 4,000 feet on Wednesday with the potential to rise a bit more by Thursday. At this time, the certainty remains fairly low (about a 20-30 percent chance, depending on location) that we will observe much more than 0.50 to 1.00 inch in a 24-hour period during these two days, especially in the San Joaquin Valley. There is a better chance that the mountains will report even higher amounts of rain, at least below around 5,000 feet. Total rain accumulations of 1 to 2 inches in the Central Valley are possible during Wednesday through Thursday with even higher amounts in the lower Sierra Nevada and foothills where amounts of 2 to 4 inches are conceivable. Rainfall rates could pose challenges in terms of runoff in portions of the burn scars. It is more certain that the cool, unsettled pattern will last for much of next week. We will monitor for the possibility of roadway flooding and debris flows at some of the burn scars with this storm. It is going to depend on whether we can tap into additional subtropical moisture in terms of snow levels rising even further. Confidence regarding timing/track of this storm remains low as of now. As for next Friday, we could get a brief break from precipitation, as the storm finally moves to the south. However, it may be slow to move out of our southern portions, or at least Kern County. Ensemble guidance in the extended forecast suggests continued troughing, or at least a cool pattern and possibly chances for more wet weather until the end of the month.Source: NWS
