Mammoth Mountain Weather Update

Mammoth Mountain Weather Forecast & Discussion

September 27th, 2023 @ 6 AM – Forecast Summary: The days of late Summer-type weather will come to a quick end over the next 36 hours as a deep low will slide down just to the east of the Sierra Crest Friday into early Monday.

Over the next 48-72 hours, temperatures will drop around 20 degrees in all areas. All areas above the 5500 elevation mark should see a full-on freeze by the weekend and into at least next Monday.

Moderate winds should return by Friday, and yes, there is some snowfall expected later Saturday into early Sunday. This morning’s data supports the first dusting of white over the higher elevations of Mammoth Mountain by sunrise on Sunday.

The snow levels look to remain above the 8500 to 9000-foot levels, possibly dropping into the upper reaches of town early Sunday.

Snowfall amounts at the 9000-foot level could add up to dusting to a couple of inches, with 1-2+ inches possible over the higher elevations.

The ground is still warm, so that will limit any accumulations. With it being so early in the Fall, expect any snow that does accumulate to melt off rapidly.

If the low tracks are a bit more west, there could be more snow than is in the forecast. SM…

Mammoth Mountain: (at the 8900-foot level) temperatures will be in the low to mid-60s through Thursday. Early morning lows will be in the low to mid-40s. Winds will be out of the southwest around 10 MPH with gusts up to 25-30 MPH.

By Friday, temperatures will drop about 5-7 degrees with a mid-day high around 55 and then down into the upper 30s for Saturday and Sunday with a 60% chance of Snow Showers.

Mammoth Lakes: (at the 7900-foot level) temperatures will be in the low to mid-70s through Thursday. With lows in the upper 30s to lower 40s. Winds will be out of the southwest around 5-15 mph, with gusts to 25 MPH possible at times.

By Friday, temperatures will drop about 5-7 degrees with a mid-day high around 65 and then down into the mid-40s for Saturday and Sunday with a 60% chance of rain or snow Showers.

Crowley & Toms Place: (at the 6800-foot level) temperatures will be in the low to mid-70s through Thursday. With early morning lows in the upper 30s to low 40s. Winds will sometimes be out of the west around 5-10 mph.

By Friday, temperatures will drop about 5-7 degrees with a mid-day high around 68 and then down into the upper 40s to low 50s for Saturday and Sunday with a 60% chance of rain showers.

Bishop: (at the 4100-foot level) temperatures will be in the mid to upper 80s through Thursday. Late-night lows will be in the mid to upper 40s. Winds will be southwest around 5-10 mph during the afternoon hours.

By Friday, temperatures will drop about 5 degrees with a mid-day high around 83 and then down into the mid to upper 60s for Saturday and Sunday with a 30% chance of rain showers.

Fall Colors: What looked to be an early start to the Fall Color season has now turned into a delayed start. I saw bits of color starting to show in many of the cottonwood and aspen trees when I drove up to Mammoth Mountain and back to Bishop on Sunday. I did see a post from Rock Creek Canyon that had higher elevation colors. Have not verified it that image was this week or last year.

Snowman

Current Satellite View

7 Day Accumulated Precipitation Forecast

7 Day Accumulated Snowfall Forecast

Temperature Forecast

Wind Forecast

8-16 Day Fantasy Weather Outlook

After this weekend’s low heads to the south and east, the EPS has some higher heights for the middle of next week, followed by weaker troughing the following weekend.

Confidence in the EPS Ensemble vs. the GFS Operational we show down the page is very low as they are not in agreement now.

The Operational GFS below has a whole new idea from the EPS Ensemble. Watch the run below; if this one came true, there could be Significant Early October Snowfall in the High Country and Back Country locations.

The GFS is not a model I trust this far out, but it’s been upgraded and nailing weather events far out the past couple of months. Let’s watch and see how this pans out.

Last nights GFS was even more off the charts with is usually hype. This model has been having runs like this with big snows and then it backs off. Fun to watch and dream about.

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Ultra Fantasy Weather Trends Outlook

45-Day EPS Precipitation Outlook – 9-26-2023

This ultra fantasy weather model updates every 3 to 4 days; it’s an excellent model to watch for trends ahead. On the run below, you can see at the end of October into early November; there is long wave troughing with cooler air over Mammoth Mountain and the Eastern Sierra. The mean at this time is trending toward precipitation around that time frame. That would be good timing for a decent opener. I can’t wait to see what the next few runs show. SM

Long Range Winter Seasonal Outlooks

ECM Seasonal Ensemble Mean Model – The next run on this model is October 5th

CFS V2 – Long Range 90 Day Precipitation Outlook – 9-26-2023

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.