Mammoth Mountain Weather Forecast & Discussion

October 27th, 2023 @ 8 AM – Good morning; this weekend’s weather will be getting cold as the area will be under the influence of an insider slider weather pattern.

The low in this type of pattern takes a track that ushers in frigid and dry air that is perfect for making large amounts of snow in a short period of time. (Please Note, I have No Idea If Mammoth Will Make Snow or Not this Weekend.)

If you’re going out for an adventure over the weekend and into Monday, expect breezy and chilly conditions, with temperatures moderating back to more seasonal by the middle of next week.

Looking at the data this morning from the Mountain currently at MC Coy Station, the temperature is 34 with an SSE wind at 7 MPH gust to 15 MPH with a wet bulb temperature of 24. Up Top, the temperature is 22, and the wind is gusting to 30 MPH at times out of the S.

5-Day Weather Forecast Details: For Mammoth Mountain, Mammoth Lakes, and the Eastern Sierra, expect mostly clear skies with just a few high clouds around at times.

Today, 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 tonight and then dropping into the upper teens very early Sunday morning and then back into the mid-20s Sunday night into early Monday 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 35-40 MPH range at times into later Friday.

Over the weekend, the wind direction will change to the North and then to the NE, winds of 15 to 25 mph with gusts in the 35-40 MPH range at times are to be expected around Main Lodge with strong wind gusts up top.

For Mammoth Lakes, mid-day temperatures will be in the low to mid-50s today and with low to mid-40s over the weekend. Night-time lows will be in the upper 20s tonight with mid-teens by very early Sunday morning.

Down at the 4100-foot level in Bishop, mid-day temperatures will be in the upper 60s today and with the upper 50s on Saturday and Sunday. Night-time lows will be heading into the freezing range, with a 22 expected early Sunday morning.

Snowman out...

 Snowmaking Forecast

10-27-2023 @ 10 AM – A very cold and dry pool of air will move into the Mammoth Mountain area over the weekend. 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 Friday, Saturday and Sunday nights if the choose to do so. 

Temperatures rebound quickly starting next Monday and that will shut the door to snowmaking into the following Friday, November 3rd. Beyond that time frame models are unclear what will happen next so we will hold off on any snowmaking forecast beyond the next 7 days.

Mammoth Mountain 10-Day Weather Discussion

10-27-2023 @ 10:21 AM – Both the operational GFS and ECMWF are in agreement on the weather pattern through day 7. An inside slider will drop into the Great Basin over the weekend and then be replaced with a strong short-wave ridge that will move into the Eastern Sierra starting on Monday.

Models then disagree with what happens on days 8-10, with the ECMWF bringing in troughing with much cooler weather and a chance of some higher-elevation snow flurries. The GFS continues with higher heights and ridging out to day 10.

Overall, models have been hitting; there will be a change in the pattern around the 11th of November, so I’m not sure what to make of last night’s ECMWF showing troughing.

We can take a look at all the data again when I do my update on Sunday.


** 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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