Mammoth Mountain Weather Forecast & Discussion

November 22nd, 2023 @ 5 PM – A short wave ridge of high pressure will be replaced over the next 24 hours with a deepening low that will slide into the Great Basin by Friday.

In the process, there could be cloudy skies forming later on Thanksgiving Day and into the overnight hours, and there will also be a slight chance of snow.

By Friday, the Low will have set up in the Great Basin (third image below), and that pattern will result in clear skies with upslope winds and much colder temperatures. This is a great pattern for snowmaking crews to lay down some serious amounts of snow.

The Great Basin Low will take its time dropping to the SE, as it will be hanging around into about Sunday.

If you plan to be out skiing and riding the next few days, expect mid-day highs to be in the Upper 30s to low 40s on Thanksgiving Day and then mid-day highs into the upper 20s to lower 30s Friday into Sunday.

Nighttime lows will be in the Teens to Lower Twenties. Snowmaking should be bountiful during the nighttime hours this weekend.

NWS Forecast for Mammoth Mountain
NWS Forecast for Mammoth Mountain
Satellite View for Mammoth
Satellite View for Mammoth
500 MB Height and Anomaly - Mammoth Weather Image
Current – 500 MB Height & Anomaly
By Friday there is a Low in the Great Basin - Mammoth Weather Image
By Friday, there is a Low in the Great Basin.
Night Time Lows are Looking Very Cold for Great Snowmaking
Night Time Lows are Looking Very Cold for Great Snowmaking
Winds over the Crest look to be in the 20-30 MPH Range at Times out of the NE this Weekend
Winds over the Crest look to be in the 20-30 MPH Range at Times out of the NE this Weekend.

Mammoth Mountain 6-10-Day Fantasy Weather Discussion

11-22-2023 @ 5:15 PM – The 6-10-day period will start with some more short wave ridging in the area, and then WAY out at days 9 and 10, there is a pattern change showing up. We have been watching this possible change on the GEFS ensemble for a while now. The ECMWF ensemble is currently on board for a change to the troughing of the west coast.

This next weather pattern may be an early weaker version of what Mammoth might see once the El Nino Winter begins in about a month. As you can see in the Upper Winds Image that is posted below, the jet stream is starting to ramp up at times as it heads across the Pacific.

Looking at the data this evening, it continues to support some snowfall moving into the area around days 9 & 10. Remember that when we see pattern changes like this, the first frontal band can often be a dud. However, that first dud can help to open the door to what follows behind.

*The content on this Mammoth Weather Page is from Steve Taylor (Snowman), Ted S (CCM), and NWS Reno / Hanford / Vegas. Model Images from Weather Bell with on Hill WX data from the Mammoth Mountain Ski Patrol.

You can see 2 small AR Bands right at the end of this .gif around Day 9 and 10
10 Day Temperature Anomaly - The Blue Colors are Cold
10-Day Snowfall Outlook Totals
Snowfall Outlook for the Next 10 Days

Mammoth Mountain 10-30 Day Fantasy Weather Outlook

** Weather Disclaimer: The Fantasy Outlooks are “Outlooks, Not Forecasts.” Some years, the wet patterns that appear in these longer range outlooks pan out; other times, the changes are always out in the fantasy period and never make it to the short-term forecast period. When all the ensemble models have agreement on wet or dry patterns, more often than not, they do seem to pan out more often then not.

11-22-2023 @ 5:15 PMThe longer-range 10-30-Day Fantasy Outlook is calling for below-average to average snowfall for the full 30 day time period. Temperatures are expected to be in the average to above average range.

Remember we have been talking about a drier then normal Fall here since September with wetter patterns starting some time later in December.

As of today models are showing a change earlier then we thought with some storminess the first week of December followed by a break and a second system just before mid month.

After that there are some major factors that are coming to play that could bring an very wet period just or after day 30. Watching all this unfold right now is like watching a suspense movie.

Pray for Snow, Snowman @mammothmountainsnowman

840 Hours Out – ECMWF Extended Ensemble Mean

Snowfall from the ECMWF Ext. Ensemble Mean

ECMWF – Seasonal Mean Precipitation Outlook – 11-5-2023 

This Model Updates Every 30 Days

ENSO – El Nino / La Nina Outlook – November 12th, 2023

El Niño Update: The current El Nino is in the strong category. How the event affects Mammoth Mountain and the Eastern Sierra this winter is uncertain. There are a lot of variables with this particular El Nino event that have not been seen during other strong events. Take a look at the video below for more information.

There are not a lot of strong El Ninos to look back at, so it’s hard to trust any of the long-range data right now. Past El Niño winters have been slow to start, so don’t be surprised if the Eastern Sierra sees below-average rain and snowfall this Fall. 

The video below is new from Mike Discussing the most current El Nino Data. All the images in this section have been updated, with what’s the most recent as of 11-12-23.

>>>> 9-29-23 – To note, El Niño winters can be slow to start, so don’t be surprised if the Eastern Sierra sees below-average rain and snowfall this Fall.

Current Weather and Information Posts

Author – Steve Taylor – The Mammoth Snowman Over the last 30+ years, Snowman has spent countless hours studying and learning about Mammoth Mountain Weather and Snow Conditions first hand. He has been skiing around the hill with marked ski poles since March of 1991 so he can measure the fresh snowfall amounts out on the hill. 

Snowman started blogging this information back in 1990 on the old Mammoth BBS system, then the RSN Forums and then on to in 2004 with Video & Photo Blog reports. (No YouTube back then). Facebook got added to the fold back in 2008 and then the Facebook Group in 2016. 

Reports, videos, and photos from the website have been featured on both local TV Stations here in Mammoth and Bishop, along with KTLA, AP, Fox, ABC, CBS, and NBC News.

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