Two storms set to give the Eastern Sierra a one-two punch
Up to five feet forecast for Sierra Crest by Tuesday
Another series of winter storms were in the forecast Wednesday, the last day of November, with the first storm expected to arrive early this morning and drop several feet of snow on the Eastern Sierra by Saturday morning.
Right after a brief break, storm number two arrives and it too is expected to drop several feet of snow on the region, perhaps even as far down in elevation as Bishop, before the snowy systems exit sometime Monday or Tuesday.
In advance of the storms, all trans-Sierra passes except Donner Pass/I-80 closed Wednesday, including Monitor Pass as well as the Bodie Road and the north section of the June Lake Loop (this section is prone to avalanches and closes temporarily during some winter storms or during portions of the winter).
The storms will likely arrive with high winds for at least part of their time in the Eastern Sierra and the National Weather Service office in Reno issued a Winter Storm Warning for today beginning at 4 a.m. and lasting into Dec. 2 at 10 a.m., with another such warning likely for the second storm forecast to arrive Saturday or Sunday.
The Winter Storm Warning means forecasters expect travel to be difficult or even impossible at times due to blowing snow, low visibility, avalanche danger and more.
“Prepare for rough travel late tonight through early Friday morning across the Sierra and northeast California and be ready for significant delays and even periodic road closures during the height of the storm Thursday into Thursday evening,” according to the Reno office of the NWS.
The agency stated that travel will become increasingly difficult in some parts of the Eastern Sierra region today as snowfall rates increase to two to three inches an hour with heavy snow reaching the foothills and Eastern Sierra through Mono County this afternoon and evening.
The high end of the snow forecast for the two storms together is about five feet on the higher elevations of the Sierra Crest, with about half that in Mammoth and less than that east of U.S. 395, Mammoth forecaster Howard Sheckter said.
That said, even Bishop could see several inches of snow before the storms exit due to the cold nature of these storms, forecasters said.
Forecast details
According to Sheckter, each of the incoming storms is an almost classic old-style “Pineapple Express” type of storm, now more commonly called an “atmospheric river” storm, or “AR,” which combines a plume of subtropical moisture coming north from the Hawaiian Islands area to intersect with a cold polar jet coming south from Alaska.
The combination of the two patterns creates some of the state’s “best storms” and, in this case, the storms are aimed squarely at the Central and Southern Sierra, Sheckter said.
“The precipitation begins Wednesday night in Northern California and should get to us about 6 to 7 a.m. (this) morning,” he said. “Thursday day into Friday mid-morning will be our highest precipitation times, with heavy snow likely lasting all day and into the night.”
Then, a second system drops down from Alaska and picks up the same atmospheric river plume of moisture on Saturday, he said, resulting in another round of heavy snow before it exits sometimes Monday.
“It will be a one-two punch,” he said. “That’s why we could see three to five feet by Monday. That and the fact it will not start off as rain like the last big storm but will start most likely as snow. In fact, it looks like it will all be snow.”
The “one-two punch” Sheckter noted is laid out in more detail by Tahoe forecaster Bryan Allegretto in his “OpenSnow” forecast for this week: “The latest model runs show that the low that the Thursday storm taps into off the coast may actually still be off the California coast by Saturday with the next storm possibly drawing in moisture from it as well into California.”
According to Allegretto, the American model suggests snow could return as early as Saturday afternoon with other models holding off until Saturday night into Sunday with another one to two feet for the mountains possible.
Long term
Allegretto stated that the long-range models suggest the trough over the West shifts east next week and the storm track may be shifted well to the region’s north for most of the week.
“We are on the cold side of the high-pressure ridge in the northeast Pacific, so the temperatures should stay fairly cold,” he stated.