First of All, on the Mono Lake area, there is strong Pogonip fog in process at 9:30am this morning. If you are traveling into that area by car, turn on your defrosters and heat the windshield,  to prevent glass related ice fogging. The fog should burn off later today. As winds increase due to the upcoming pattern change, the fog should not return tomorrow morning.

Here is the latest update on the upcoming storm and latest Quantitative precipitation Forecast.

The latest precipitation forecast from the California Rivers Forecast center shows very light snowfall developing Tuesday afternoon in the town of mammoth and upper elevations. Amounts will be in the 1 to 2 inch range in town and 3 to 5 inches on Mammoth Mtn by 4:00am Wednesday.  24 hour amounts for Wednesday in town will be in the 4 to 6 inch range with 6  to 12 inches on Mammoth Mtn by 4:00am Thursday.  Thursday; up to a foot in town and 15 to 24 inches over upper elevations. Expect Platinum Powder conditions Friday with Snow to water ratios possible at 15:1. So another foot is possible by Christmas morning on old Woolly. During the period Saturday through Tuesday Am, an additional 1 to 2 feet is possible over the upper elevations between Christmas and the following Tuesday. Of course all this will be subject to change as new guidance comes out every morning.


Evolution of pattern:

The latest  GFS ensemble run begins to show some hint of where the pattern is going.

The GFS 5 day means show the current position if the Eastern PAC Ridge at 160w north of Kauai and and amped. This positions the long wave Trof at 130west and strongly positively tilt. Over the next two weeks that ridge shifts east to 155w but most importantly deamplifies, so that the LW trof shifts to the western Great Basin by years end. This is a colder and drier pattern one that brings either outside or possibly Inside sliders. Cold, showery, windy pattern that possibly begins the new year. The models have been struggling with both the MJO and the various global models for the end of week 2.  My gut feeling is that the long wave trof will remain in the west, either out over the Eastern Pac or the Great Basin for the foreseeable future keeping the east milder than normal and the west stormy. I do not think that it is just coincidental that the EP high seems to like the Central North Pacific with the warm water pool sitting Beneath it. The next move would be reamplifacation to redevelop the western trof westward.  Snowfall;  with shift of the LW trof eastward, it is less likely that excessive snowfall amounts will occur over the next week or 2. And although many of the GFS deterministic runs of the GFS are still touting much larger snowfall amounts for our Sierra, they seem over done without a moderate or strong AR.  Nevertheless, 5 to 7+ feet of snowfall is nothing to sneeze at, especially during COVID. 😷