Mammoth Mountain Weather Forecast

Thursday, October 24th, 2024 @ 10 AM – Good morning, and welcome to our Mammoth Weather Page. The weather in Mammoth looks tranquil now through the upcoming weekend.

However, some significant changes will occur next week, as a deepening low-pressure system coming in as an inside slider will affect the area.

Monday into Tuesday, look for a 20-30 degree temperature drop, along with light snow showers and breezy conditions developing.

Snowfall accumulations will be low next week, in the 1-2 inch range. Snowmaking conditions should be prime for making tons of snow at night most of next week.

(LIVE) Mammoth Mountain Top of the World Webcam — **(LIVE) Mammoth Mountain Top of the World Windowcast Webcam**

Short-Term Forecast into Friday: Midday temperatures at the Main Lodge (8,900 Feet) will be in the upper 50s to lower 60sr. Overnight lows will be in the mid-30s tonight and then in the upper 30s to lower 40s.

Winds around Main Lodge will be out of the SW at 5-15 MPH, with stronger gusts, especially over the upper mountain.

In Mammoth Lakes, midday temperatures will be in the mid to upper 60s through Friday. The overnight low will be in the low to mid-30s.

For Bishop to Mill Pond, mid-day highs will be in the upper 70s to lower 80s into Friday. Overnight lows will be in the mid-40s. Expect light winds during this time frame.

NWS Service Forecast for Main Lodge & the Mammoth Lakes Basin @ 8900 Feet in Elevation

Current North East Pacific Infrared Satellite Image — (Live Feed) North East Pacific Infrared Satellite Image

Mammoth Mountain Extended Outlook Discussion

Day 1-7: Warm and dry, tranquil weather will give way to a significant cooling trend as a deep low-pressure system slides into the western side of the Great Basin Monday into Tuesday.

When systems drop in on the east side of Mammoth Mountain like this, they are usually dry with very limited snowfall. The main effect is the cold air, which is excellent news if you want to make snow.

This slider is far enough west that it should produce some light snowfall, with possibly an inch or two falling above the 8,500-foot level by Tuesday night.

For the 8-14 Day time frame: By day 8 on the ECM ENS, the following system in the flow will be moving into the northern parts of the Great Basin as the low quickly progresses to the east. That low will be followed by a progressive ridge that looks to move out of the area around day 14 / November 7th.

10 Day - ECMWF 500mb Height Anomaly Outlook — 10 Day – ECMWF 500mb Height Anomaly Outlook

10 Day GEFS 500mb Height Anomaly Outlook — 10-Day GEFS 500mb Height Anomaly Outlook

Ultra Fantasy Outlook for November: Overall, my outlook for the month would be for 2-3 low-pressure systems to move through the area with moderate to solid ridging between systems. Snowfall is expected to be a bit below average.

There have been six weak La Nina Novembers over the last 24 years; here is what happened with the snowfall on Mammoth Mountain at 9,000 feet.

2000-2001 – November Snowfall 22.8
2005-2006 – November Snowfall 23.4
2008-2009 – November Snowfall 26.5
2016-2017 – November Snowfall 19
2017-2018 – November Snowfall 34
2022-2023 – November Snowfall 61

Looking at all the Fantasy Long Range Outlook data from last week, most of the more extended ensemble models support what we have seen from weak La Nina Novembers from the past.

Steve Taylor – The Mammoth Snowman

November Snowfall Outlook from the ECMWF Weeklies

Mammoth Weather Forecast Data from Weather Bell

ECMWF Ensemble Jet Stream Gif

This is the Northern Pacific View of the ECMWF ENSEMBLE Run of the Jet Stream.

Temperature Forecast GIF

*Temperature anomaly means a departure from a reference value or long-term average. A positive anomaly indicates that the observed temperature was warmer than the reference value, while a negative anomaly indicates that the observed temperature was cooler than the reference value

The Wind Forecast

The wind forecast for the next few days calls for a southwest flow. Wind speed at the 8900-foot level will be 5-10 MPH with gusts in the 15-25 MPH range during the afternoon. Winds will be gusty at times up to in the 35-40 MPH range this week. I will have more detailed on mountain wind forecasts once the ski area reopens for the winter season.

QPF Forecast

Snowfall Forecast & Outlook Images

Winter Outlook as of October 11th, 2024

Thinking about potential snowfall and the upcoming winter season is getting exciting. Let’s take a look at what this upcoming snowfall season might hold.

The first issue in looking out into the weather for the snow season in mid-October is simple. Many of the factors that will come into play to influence this upcoming winter won’t be on the table until 4-6 weeks from now.

What we can do is look at the ENSO factor. With the newest seasonal long-range fantasy model run in, the ECMWF Seasonal has a weak La Niña in place through at least January.

During February, the La Nina looks to fade to natural, adding a whole new factor to the second half of the Winter Outlook that we won’t touch this far out.

Below are the winters considered weak La Ninas over the last 30 years. One was a drought season, one an average winter, and four above-average winters. 2023 was the largest winter ever recorded by Mammoth Mountain Ski Patrol and DWP.

2000-2001 – Total Snowfall 393
2005-2006 – Total Snowfall 578
2008-2009 – Total Snowfall 470
2016-2017 – Total Snowfall 617
2017-2018 – Total Snowfall 262
2022-2023 – Total Snowfall 721

The ECMWF Seasonal (see images below) updated this month shows the snow season starting with average snowfall for November and December. Beyond that, snowfall lags below average for January and February, with an average March being shown way out in Weather Model Neverland.

As we wait for the snow season, remember that La Ninas are much like El Nino winters. There is no one specific outcome; you can get massive snowfall or a total bust.

Let’s keep the positive vibes that Mammoth Mountain gets a perfect winter, with moderate amounts of powder snow mixed in with some dry periods with endless wind-buff days.

Steve Taylor – The Mammoth Snowman

PS: The next update for this snowfall section will be 11/6/24.

La Nina Years Snowfall Totals for Mammoth Mountain

Weak La Nina
1971-72 Snowfall Total = 268 with 139 in December
1984-85 Snowfall Total = 236
2000-01 Snowfall Total = 393 with 124 in February
2005-06 Snowfall Total = 578 with 4 100+ inch snowfall months
2008-09 Snowfall Total = 470 with 2 100+ inch snowfall months
2016-17 Snowfall Total = 617 with 245 January 163 February
2017-18 Snowfall Total = 262 with 142 in March
2022-23 Snowfall Total = 717 – Largest Winter Recorded over the last 100 years

Moderate La Nina
1970-71 Snowfall Total = 255
1995-96 Snowfall Total = 321
2011-12 Snowfall Total = 263
2020-21 Snowfall Total = 244.5
2021-22 Snowfall Total = 260

Strong La Nina
1973-74 Snowfall Total = 306
1975-76 Snowfall Total = 197
1988-89 Snowfall Total = 251
1998-99 Snowfall Total = 323
1999-00 Snowfall Total = 382
2007-08 Snowfall Total = 333
2010-11 Snowfall Total = 668

Last Update from DWP Precipitation for Mammoth Pass & the Eastern Sierra

*Mammoth Mountain and Eastern Sierra Weather is updated on Sunday, Tuesday & Thursday by local Steve Taylor, the Mammoth Snowman. The goal is to provide detailed weather forecasts presented in an easy-to-read format. This isn’t a Hype, one-and-done model-run website. It’s just the basic facts from how I see it after 40 years of being involved in local weather and recreation. And yes, I use Weather Bell for my forecasting data. Snowman