Mammoth Mountain Weather Forecast & Discussion

October 25th, 2023 @ 8 AM – Good Afternoon; there are several weak Lows that will bring cooler Fall weather to the Mammoth Area and across the Eastern Sierra over the 5-day period. All of these systems have limited to no precipitation with them for Mammoth Mountain.

The one system that does have a small amount of moisture moves through tonight. The HRRR model shows .03 to .05 of QPF for the Sierra Crest at Mammoth Mountain. That QPF could lead to a small dusting of white over Mammoth Mountain by Thursday morning.

With each of these lows, the air will further cool in the area. The weekend system will have a full northerly flow with it, bringing the coldest temperatures of the Fall into the area.

The Snowmaking Crew will be able to work some magic when that cold air hits. Scroll down to the next section for the Full Snowmaking Forecast & discussion.

5-Day Weather Forecast Details: For Mammoth Mountain, Mammoth Lakes, and the Eastern Sierra, expect cloudy skies over the high country tonight with a few snow showers. Skies will then be pt cloudy into Friday and then clear on Saturday and Sunday.

Today into Friday, mid-day temperatures out on the Mountain @ the 9000-foot level will be in the low to mid-40s. Night-time lows will be dropping a bit each night, with upper 20s to low 30s tonight and then dropping into the mid-20s early Saturday morning, with possible upper teens by early Sunday morning.

The Wind Forecast through Sunday has breezy conditions for the high country. Expect southwest winds of 15 to 25 mph with gusts in the 35-50 MPH range at times into Sunday.

For Mammoth Lakes, mid-day temperatures will be in the mid-50s today and then lower 50s on Thursday and Friday. With low to mid-40s over the weekend.

Night-time lows will be in the upper 20s to lower 30s the next few nights, and then by very early Sunday morning, lows could be down into lower 20s, possibly upper teens.

Down at the 4100-foot level in Bishop, mid-day temperatures will be in the low to mid-70s today and then the 60s into Saturday, with upper 50s on Sunday. Night-time lows will be heading into the freezing range, with a 23 expected early Sunday morning.

Snowman out...

The HRRR model has a slight dusting of snow for Mammoth Mountain tonight. - Mammoth Weather Image
The HRRR model has a slight dusting of snow for Mammoth Mountain tonight. The oranges and reds you see are the stronger winds right along the Sierra Crest.
You can see the forecasted moderate winds in this chart. - Mammoth Weather Image
You can see the forecasted moderate winds in this chart.

 Snowmaking Forecast.

10-25-2023 @ 1 PM – The seven-day forecast is looking decent, as there will be a transition to colder air in the area by early Thursday. From there on out, the Snowmaking Crews will be able to make snow nightly all the way out to next Tuesday Morning.

The Snowmaking conditions will be low-end on Thursday and Friday and then will be about perfect by early Sunday and into Monday Morning.

If the temperatures we are seeing on the models pan out, the snowmaking team should be able to blow a ton of snow on Broadway. Remember, those fan guns blow 3-5 times more snow overnight than the old snowmaking guns they used to use.

Longer Range Fantasy Outlook for Snowmaking (8-14 Days) Some of the models keep enough cooler air around for marginal snowmaking during this time period. If riding builds in, as shown on the ECMWF, snowmaking is going to shut down for a while the week of the opener. 

NBM - Snowmaking Temperatures for Mammoth Mountain Ski AreaMammoth Mountain 10 Day Weather Discussion

Updating on 10-26 @ 11:50 AM… check back later. We lost all power for hours yesterday…


** 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.

Mammoth Mountain 30 Day Fantasy Weather Outlook

October 23rd, 2023 @ 2 PM – The longer-range fantasy outlook is calling for below-average snowfall during November with below-average temperatures.

Overall the pattern looks to be one of a broad long wave trough for the west, with several weaker systems moving through the flow and making their way towards Mammoth Mountain before the Thanksgiving Holiday. The Snowmaking Crew should have good nightly runs with a pattern like this.

I am fairly sure that at some point, something moderate will develop within the flow, and there will be a decent snowfall over the Mountain. Over the years, the magic date has always been November 11th; right around that date, Mammoth Mountain, more years than not, would get an opening snowfall.

Everyone needs to also take into account that El Nino years that do end up being wet are, in most cases, backloaded with the big snows of winter hitting around the holidays and then lasting into Spring. A lot of the El Nino November’s have turned cold, so that would be great for snowmaking. 

840 Hours Out – ECMWF Extended Ensemble Mean

840 Hours Out – GEFS Ext Ensemble Mean

November Height Anomaly – CFS Daily

840 Hour Snowfall from the ECMWF Ext. Ensemble Mean

840 Hour Snowfall from the GEFS Ensemble Mean

Temperature Anomaly – ECMWF Ext. Ensemble Mean

30Day-Temp_anomoly-ecmwf-weeklies-avg-california-t2m_f_anom_32day - Mammoth Weather Image

ENSO – El Nino / La Nine Outlook – September 26th, 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 on there as of 9-26-23.

> 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.

SSTA Mammoth Weather Forecast
SSTA Mammoth Weather Forecast

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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