Foggy valleys under weak ridge will give way to clearing skies as winds increase Sunday night into Monday…..

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. 😷

Fab Weekend in Mammoth….Clear skies calm winds and plenty of snow! More on the way…Might be excessive…Well see..


sudden stratowarm  event first week of January…


Its a shoe in that the new week will bring a lot of snowfall. Were talking 5 to 6 feet in town beginning Tuesday PM with possibly 6 to 10 feet on the upper mountain by the 27th of Dec. A Christmas Eve and Christmas day that most wish were up here to share.  Questions remains, what happens after the Christmas weekend. Will the long wave progress into the Great Basin turning the pattern drier with modified Arctic Air, or will the Eastern Pacific Ridge retrograde again, backing westward to get it going all over again!.  There is no clear answer at this time.   The drier scenario brings some really cold weather with snowfall that is not so extreme for a time, before we ridge up up around New Years. The Retrogression scenario shows us how deep the rabbit hole will go with massive amounts of snowfall with no sense of end in sight. Sure which I took the blue pill!  Sound familiar?


More Later………… 🙄

SnowMegeddon! Week two suggesting storm after storm through years end!


Todays guidance and the ensembles, continue the trend, that this stormy period for California is just beginning and that it is likely to continue beyond Christmas. The main point here is that the eastern pacific ridge “retrogrades” during week 2 ) next week and that pulls the long wave west for more storms with good moisture taps. Snow Megeddon is an eastern colloquial term that is being used for not one storm but the accumulation of many between today and years end.  There is a particularly large one, that will possibly hit around Christmas, the timing will be better kn own by this weeks end,  A lot will depend upon how strong the AR is.  There seems to be several weak ARs in store for the high country through years end.

The Dweeber……………………….:-)


So the models are in this afternoon and all are in agreement that the pattern will remain active through the 28th. It will not snow everyday as there looks to be a break developing some time next Friday into Sunday. The QPF suggests a solid 10 inches of water through next Friday. Somewhere between 8 and 10 feet of snowfall over the upper elevations for Mammoth MT is still reasonable for the combined two storms. There looks to be a break next weekend., however, the following week will bring the opportunity for more moderate to heavy snow producing storms as well.  Next week the main the upper jet seems to favor the southern half of the state more than Northern California. Good for both the Southern and Central Sierra, Good for Mammoth! .  Amounts will be updated later this week but preliminary Est are some 4 to 6 inches of water, (without a major AR). I say that as although all model runs do not show a major AR in many runs, there are enough ensemble members that still have it considered, so only time will resolve this issue. If we do have a Moderate or Strong AR, then all bets off on snowfall next week as it will be, “Snow Megeddon!”  Most likely time frame around Christmas.

This Monday Tuesday storm has a very low end moderate AR (barely Level 2) So far, it appears that this Monday-Tuesday storm will bring the heaviest snowfall totals in the shortest period of time.

BTW, the IVT forecasts from the GFS show the potential for a weak AR on the 23rd and the European, a moderate AR on the 26th.   It seems that the idea of a significant AR keeps is still in the cards, it is still possible and until we get closer to the week 2 period, we can only watch with interest.

In the meantime, I expect Mammoth Mt to have the best Christmas and New Years Week skiing, in several years!!


Happy Holidays!!


Dr Howard and the Dweebs……………….:-)