Mammoth Mountain Weather Forecast & Discussion

October 1st, 2023 @ 3:24 PM – Seeing snow on the peaks out the office window this morning was lovely. The first dusting fell early Saturday before sunrise, and then on Saturday evening and into the overnight hours, more snow fell from Bishop Creek Canyon up to Mammoth Mountain.

The snowfall never amounted to as much as the data we looked at supported, so it was a bit of a bust. I think that is good news; at this point, most people would rather have another month of hiking and biking without the snow. Mammoth has not even been closed for two months yet from last winter.

Moving forward, the weather story will be just above average temperatures, with dry conditions expected for the next 2-3 weeks. This week into Friday, expect a slow warming trend with temperatures coming up about 15-20 degrees from the temperatures forecasted for Monday.

The upcoming weekend should be perfect for those coming up to check out the peaking Fall Colors expected in many locations above the 8500-foot level.

Looking at the more extended range data that is posted down the page, the next change in the weather could be around October 21st; until then, enjoy the Gorgeous October Fall Days.

Snowman

10-1-23 - There was a second dusting of snow last night on Mammoth Mountain. — 10-1-23 – There was a second dusting of snow last night on Mammoth Mountain.

Mammoth Mountain: (at the 8900-foot level) On Monday, temperatures will be in the low 40s, with temperatures rising during the week into the upper 60s by Friday into next weekend. Early morning lows will be in the low to mid-30s Monday AM and then will be into the upper 30s to low 40s by Friday into next weekend. Winds will be in the 5-10 MPH range this week and into next weekend.

Mammoth Lakes: (at the 7900-foot level) On Monday, temperatures will be in the upper 40s, with temperatures rising during the week to near 60 by Friday into next weekend. Early morning lows will be in the low to mid-30s Monday AM and then will be in the upper 30s to low 40s by Friday into next weekend. Winds will be in the 5-10 MPH range this week and into next weekend.

Crowley & Toms Place: (at the 6800-foot level) On Monday, temperatures will be in the low 50s, with temperatures rising during the week to near 68 by Friday into next weekend. Early morning lows will be in the upper 20s to low 30s Monday AM and then will be in the upper 30s by Friday into next weekend. Winds will be in the 5-10 MPH range this week and into next weekend.

Bishop: (at the 4100-foot level) On Monday, temperatures will be in the low 70s, with temperatures rising during the week to near 80 by Friday into next weekend. Early morning lows will be in the upper 30s Monday AM and then will be in the upper 40s by Friday into next weekend. Winds will be in the 5-10 MPH range this week and into next weekend.

Snowman

Satellite View

7 Day Accumulated Snowfall Forecast

Temperature Forecast

Wind Forecast

8-16 Day Fantasy Weather Outlook

Updated 10-1-23 – Higher heights with some weak troughing around the 10th with more warmth beyond that time frame. Overall, the next 21 days look high and dry, with a bit above-average temperatures for October. The next chance for a significant change in the pattern will most likely be around October 21st when the pattern is expected to change again. Hopefully, that change will be to cooler weather with snow showers at times. Snowman

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45 Day Ultra Fantasy Weather Outlook

Day 16 – 45 ECMWF Extended Ensemble Mean

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Longer Range 90 Day Weather Trends

ECMWF Seasonal Ensemble Mean Model

This model seems to have the most likely outcome over the next three months. The one factor the model could be missing out on is if a Super Typhoon would get caught up in the westerlies in the latter half of October into early November. Those types of systems can quickly throw Fall into the above-normal precipitation range. With systems like that, there are high snow levels above 9000 feet or higher, just like we saw in late October 2021… confidence in this model’s outcome is low to moderate at best.

CFS V2 – Long Range 90 Day Precipitation Outlook – 10-1-2023

The CFSv2 that so many people love continues to flip flop from wet to dry to wet and dry again for the start of the season. Here are a couple of the last runs showing what I am talking about. Lot’s of uncertainty at this time on the CFS regarding what happens with precipitation over the next 3 months.

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.