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Weather Update — September 23, 2026

September 23, 2026MammothFMNoé
mammothradioeastern sierra weather

Transcript

My friends…

Today is Wednesday, September 23rd, and I’m Noé from eastsideweather.com, here for MammothFM in the Eastern Sierra, coming atcha with your local weather report…

Monday’s showers brought an early taste of winter to the alpine, with many high peaks being dusted with snow, and some areas like the white mountains getting a thorough coating. Some flurries were observed on top of Mammoth Mountain, but it didn’t stick to the ground. In Mammoth Lakes, it drizzled on and off. Other areas received more substantial rains, like the Sierra Crest to our south, and Bishop, which reported over a quarter inch of rain! By Owens Valley standards that is a pretty substantial rainfall, especially for this time of year.

This week, high pressure briefly returns which means above average temperatures, and beautiful, clear fall weather. By early next week, another weak trough may bring slightly cooler temps. After this, warm and dry fall weather appears to be favored longer term.

I will point out that this has been shown in models for a while now in the extended range, while troughs have continued to appear in the short range, so we’ll have to see whether this pattern sticks.

One factor that could complicate things this fall is the extremely active eastern pacific hurricane season, which is being driven by our historically strong El Niño. Hurricane Polo experienced an explosive intensification, and is now the second strongest storm in eastern pacific history, behind only hurricane Patricia, which formed during the last super El Niño of 2015-16. These hurricanes usually end up tracking WNW over open water, but occasionally they can send their moisture to the Southwest and California, or less commonly their remnants. Eastern Pacific Hurricane season is expected to remain quite active through October, so things can change surprisingly quickly with one of these events. While I’m not currently expecting any major impacts to the Eastern Sierra from Hurricane Polo, with only a small percentage of scenarios showing any precipitation here at all, we do need to keep an eye on the tropics for the remainder of fall to see if any remnant moisture might come our way.

Speaking of El Niño, we are currently experiencing the strongest event in instrumental history, and it is only going to keep intensifying for the next few months. And, it is certainly drumming up quite a lot of hype. I’d like to talk more in depth about it soon to separate fact from fiction. Is it time to build an ark? Is Mammoth going to see another BIG WINTER? I’ll get into it soon, but for now my advice is to be wary of anyone speaking with any measure of certainty. If you will recall the El Niño winter of 2015-16, forecasters were calling for a major winter in California, which ended up being pretty average.

In other news, the Dome Fire continues to burn in Yosemite National Park, reaching over 3500 acres and 15% containment. As high pressure briefly returns this week, fire activity could pick up as well as more widespread smoke impacts.

And now the weather for this week:

In Mammoth Lakes and surrounding areas:

  • Wednesday: Sunny, with a high of 73, and an overnight low of 48. Patchy smoke is possible in the evening
  • Thursday: Sunny, with a high near 72. Winds of 5-10mph out of the southwest with gusts up to 25 mph. An overnight low of 49
  • Friday: Sunny, with a high near 66, and an overnight low of 43

Now over to our friends in the Owens Valley:

  • Wednesday: Sunny, with a high near 87. Winds picking up in the afternoon, with an overnight low of 53
  • Thursday: Sunny, with a high near 88 and an overnight low of 52
  • Friday: Sunny, with a high of 86, and an overnight low of 51

This has been Noé for MammothFM in the eastern sierra. Join me over on eastsideweather.com where you can get a detailed weather forecast for anywhere in the eastern sierra, and read my longer range weather outlooks