"Winter Storm Warning" goes into effect Saturday, as much as several feet of snow expected by Tuesday
Two winter storms capable of dropping at least one and a half feet of snow are forecast to hit the Eastern Sierra in the next few days, with the first one coming in Saturday afternoon and lasting into Sunday and the second one coming in Monday and lasting into Tuesday, according to the National Weather Service.
The first storm is considered by the NWS to be the most reliable in terms of snow levels and amounts—about one and half feet of snow above 9,000 feet—with the second storm forecast to come in with slightly less snow at this time.
The first storm will begin sometime Saturday afternoon, with the heaviest snow coming during the night. As of this morning, Friday, March 28, the NWS has posted a “Winter Storm Warning” from Saturday at 5 p.m. to Sunday, 5 a.m.
The second Monday/Tuesday storm, which Reno NWS forecaster Jon Middlestadt said is still a “bit tricky” to pin down, is expected to drop a slightly lesser amount of snow, although he also said that could change if the timing of the Gulf of Alaska cold front hits the Pacific Ocean moisture plume “just right” to bring the maximum amount of snow to the Central Sierra where Mammoth lies.
“The Monday/Tuesday storm will be a bit colder, so that typically sets you up for a higher snow to water (content) ratio, but the first storm, while warmer, (warmer storms typically drop more of their precipitation as rain versus cold storms, which lead to more snow) is also tapping into a moderate atmospheric river plume of moisture with connections to the subtropics, which is significant,” he said. “That’s why at this time, we believe the first storm will bring you the most moisture.”
However, Mammoth’s amateur weather forecaster, Howard Sheckter, thinks at least in the case of the first storm—and maybe the second—the NWS is being overly conservative.
“Two significant storms headed for the high country,” he wrote on his web page Friday, March 28. “Each has a good chance to bring about two feet over the crest and a foot plus to the towns of Mammoth and June. What is interesting about the first storm is the coupling of both subtropical and polar jets off the California coast. The best focus for the heaviest precipitation will be over the west-facing mountains of Northern California, where the upper jets focus the highest moisture transport… for a longer period then the Central Sierra."
That still means the first storm will be a significant one for the Mammoth area; areas north, however, will likely get even more snow.
"In looking at the new… data, they give Yosemite only (.90 inches) of (moisture content)," he wrote. "The Dweebs believe this is way underdone, as that amount would only put about 10 inches to 12 inches over the crest with orographics. Considering the pattern… I like (the model that shows) between 1.5 inches (of water content) and 1.75 inches for the Mono County Sierra and (an) amount (of) up to two feet over the crest seems more reasonable considering the pattern. Sunday looks snow showery with little if any additional accumulation.
“The Monday storm is the last in the series. …the upper jet is cyclonically curved and punches in from the west, right over us. It is cold as well… Although the (water content) is similar, I expect more from that storm because of the higher snow to water ratios.”