Arctic Ribbon on the way to bring serious chill to the high country and provide first Platinum Powder for the Season Sunday night and Monday…..Cold weather will be initiated by strong winds Sunday/Sunday Night….Expect Strong Wind Chill Factors Sunday night and especially Monday AM over upper elevations….Well Below Zero…..

5:25PM Sunday:

Arctic Ribbon coming through now…. In back…very cold air to pour in,  all night and through 4:00AM Monday….


Revised 12:15AM Sunday

Winds Gusting to 108MPH over the Summit at the moment….


A an Arctic Ribbon will pass through Mammoth by 4:00PM Sunday.  The storm system that has been forecasted to moved mainly through the Great Basin has taken a track more over California now. The main idea is still that no moisture will be entrained into the system from the west. However, this system is so cold, that it will squeeze most any moisture left in existing air mass out of it.  Behind the Ribbon and front will be a period of upslope.  There are lots of possibilities here from strong Mono Lake effect for Lee Vining and June Lake to good upslope snowfall for Mammoth Mt. The action of this pattern change with storms now dropping south over the far west this week will do much to empty the Arctic Reservoir of the Extreme Cold that has built up over several weeks over Central Canada….

Mammoth Mountain may receive some 6 to 8 inches over the crest, 3 to 6 inches at the Main Lodge and here in town some 1 to 3+ inches between Sunday night and Tuesday AM. With snow to water ratio’s of 20:1 expected, true Platinum Powder conditions will exist on Mammoth MT, Sunday night and Monday.  It will be cold Monday AM with lows about 5 degrees in town.  However daytime highs will stay in the low 20s. It will remain windy over the upper elevations Monday and breezy in town.  One more thing….The Wind Chill Factor.  You will need to ware face protection to ski/board Monday as wind chills will range between -15 and -30 over the upper elevations.  This is especially true for the morning Monday for you powder lovers.

The fact that this weather system is coming in further west than earlier forecasted is a very good sign of retrogression!   Odds are, that subsequent storms will now come in from a more westerly direction with over water trajectory, especially by the end of the month of February and Early March.  This means that the likelihood of significant snowfall is in our future over the next two to 4 weeks.


Stay Tuned!


Dr Howard and the Dweebs…………………:-)

Chilly Thursday will be followed by moderating temps over the weekend…..Another Cold Trof will Dig into the Great Basin Sunday Night with Light Snow Possible Sunday Night and Monday….

12:15PM Thursday


It’s not often that we get a strong Trof directly linked to the Polar Vortex over Hudson Bay. This actually happens Sunday Night into Monday as “CPK” Continental Polar Air gets pulled out of Central Canada and yanked westward, then SSE ward.  It will be cold Monday but not nearly as cold as Montana, the Pacific Northwest and the Northern Great Basin. Mammoth may struggle to get much above the low 20s Monday with nighttime lows in the single digits…..Some sensitive to cold water pipes in the area may be in Jeopardy next week.


Get used to Chilly Cold Weather….more often than not as a Long Wave Trof Set up over the Great Basin. Although milder temps are expected this weekend, a Cold Digging Upper Trof will Reload the long wave over the Great Basin early next week for temperature’s some 15 to 20 degree below normal Monday and Tuesday. That’s highs in the 20s in Mammoth this time of the year. Since the bulk of the Cold Air is to the east of us and not over the Ocean, this will be another storm highlighted by Wind..Light snowfall (1 to 6 inches),  and down right Cold days and Nights. Expect winds to pick up Sunday as the upper jet descends over Eastern CA Sunday Night…..  A long wave Trof is forecasted in the mean,  to remain over the Great Basin in the 6 to 10 day Outlook with the possibility of some retrogression by months end with an increase of retrogression the first week of March.  Climate models showing the possibility of a wet first week of March with snowfall in the high country.


Dr Howard and the Dweebs…………………:-)

Change in Pattern in Process with Cooling, Windy Periods and Light Snowfall Likely through Tuesday……Further Retrogression Possible Toward Months End….

Monday Afternoon 4:15pm

It was a cold day today. I almost forgot how it feels when its cold!  Highs were in the mid to upper 20s.    Mammoth Mt reported 3 to 5 inches of cold dry powder this afternoon.  With a little luck maybe we’ll double that!  Yes, the upslope portion of the storm chatted about for tonight looks more likely for South Central Mono County as a Deformation Zone sets up, where the upper flow bends from the SW……then returns around the upper low off shore tonight.  The big question is,  where exactly will it set up? It could be north of Mammoth near June Lake/Conway Summit or….Mammoth Lakes to Crowley Lake. We’ll know where it set up by Tuesday morning as there will be people saying…….Where did all this snow come from?   😉

Longer range is looking colder with Modified Arctic on the way a week away and yet another shot of Arctic air around the 18th to the 20th.  With a little luck, if the upper ridge retrogrades enough, we’ll be touting a Platinum Powder Alert! for that time.   Platinum Powder Alert Criteria is 12 inches of snow or more at a snow to water ratio of at least 15:1 at 10,000 feet over a 12 hour period.


Monday AM:

Forecast remains on track with light snow expected to continue today into tonight….Light accumulations expected…..

With 2 inches now on the ground now on Mammoth Mt, and another 2 to 3+ inches still possible into Tuesday morning…..The forecast appears to be on track….

The Eastern Pacific ridge remains amplified and positive tilt, allowing the formation of a closed low to develop over the Great Basin today with unstable air aloft. As the closed center passes over the top of us and moves off the South Central CA coast early Tuesday AM….. through the process, some upslope precip is certainly possible.

There is a slight chance that a weaker system may kick off some more snow showers Wednesday Night.

Highs today Monday will be in the upper 20s, and then up to the low 30s Tuesday, then upper 30s/Lower 40s by Mid week…….Lows at night will be in the single digits and teens through Thursday AM.  Expect teens and 20s Friday and Saturday…..

Expect moderating temperatures Friday into Saturday with highs in the upper 40s and lower 50s…..It will become windy again by late Saturday afternoon or night, then especially Sunday, as another cold Great Basin Low develops Sunday into the following Monday. More light snowfall is possible late Sunday Night or Monday a week away….It will be colder again next Monday after a mild upcoming Friday and Saturday.

This all is still considered a dry pattern for the State….

Longer Range Outlook hints at further retrogression of Long Wave Ridge, This in turn would pull the upper Trof off shore for over water trajectory. This is hinted at for the period toward the end of the month of February…..

More later this week……


Dr Howard and the Dweebs………………………:-)



Sunday AM:  9:35AM

Forecast discussion below still on track…….

QPF amounts from the mornings updated Sunday 3KM 12z WRF NAM, show an inch or two of snow tonight Sunday from the 2nd wave and between 2 and 4 inches from the 3rd system between Monday afternoon and early Tuesday AM.  So snow totals seem on track, as forecasted in my earlier discussion below.   If by chance there is a 20 mile shift in the track of the Monday nights system, we could get a bit more….

One bright spot here is that the developing pattern is much colder over the next several days and so Mammoth Mt will be able to add to the natural snowfall with a bit of their own via snow making….


Dr Howard and the Dweebs………………………:-)



Latest guidance including the Saturday 12Z NAM is showing several waves that will move through Mono County Through this Tuesday.  The first wave and front is expected to flush through Mono County Saturday by mid-afternoon with a wind shift from NW to N to eventually NE tonight.  Winds are not expected to be strong today even over the crest with strongest winds with possible gusts to 50mph holding off by late afternoon and tonight.  So breezes in the 15 to 30MPH range most likely over the higher elevations mid day.  This wave is dry with no precipitation expected today Saturday.  Just mainly breeze and cooling. Todays highs will range up to 50 degrees in the Town of Mammoth to only 30s and 40s on Mammoth Mt.  That is compared to the low 60s in town on Friday.

The following wave is stronger as it comes SE to the Oregon Coast then digs south down the Northern CA Coast before turning inland north of the Bay Area Sunday evening. This colder system has a little over water trajectory and may bring some flurries to light snowfall sometime Sunday afternoon or night especially over the higher elevations. Winds will also be stronger with this wave and will be quite noticeable, especially later in the afternoon Sunday then stronger yet Sunday night for a short period. This is even true for the lower elevations of Mono County where gusts to 50MPH through some of the Valleys are possible. Highs on Sunday will be down into the 40s at 8000 feet.

The third and final wave has initially less over water trajectory than Sundays wave but makes up for it later. The System depicted by the 12Z -12KM NAM has a closed 500MB center located over Alpine County south of Tahoe at 4:00PM Monday  where it continues to spin up that night as its center digs off the South Central CA coast.  At the moment this track favors the potential for a good period of upslope snowfall for Southern Mono County southward, especially Monday night into Tuesday AM. However, the 3KM 12Z Saturday NAM, shows some very light snowfall developing Sunday Night from the 2nd wave, before the 3rd wave generates upslope snowfall, mainly Monday night into Tuesday Morning. The QPF from the 3KM NAM shows totals of 2 to 4 inches by Tuesday AM with isolated areas getting up to 6 inches of snow, mainly from Upslope Monday overnight.


High temperatures will be in the 30s Monday and Tuesday…More seasonal for February!  🙂