Powder Forecast – Friday, May 1st, 2026
Ted Schlaepfer CCM —- Mammoth Mountain WeatherGuy
Snowfall forecasts are valid at the Sesame snow course (Main Lodge) for the prior 24 hours as reported in the 6-7 AM morning snow report.
**Snowfall forecast confidence ranges from very low (1) to very high (5)
Sat 5/2 = 0”
Sun 5/3 = 0”
Mon 5/4 = 0”
Tue 5/5 = 5 – 7” (H20 = 0.50” – 0.70”)
Wed 5/6 = 2 – 3” (H20 = 0.10” – 0.25”)
Thu 5/7 = 0”
Fri 5/8 = 0”
Sat – Mon 5/9 – 5/11 = 0”
May Snowfall = 0”
May Forecast = 5 – 15”
Detailed 4-day Snowfall Forecast:
Sat 5/2 – No snowfall expected; chance of a late PM rain shower.
Sun 5/3 – No snowfall expected at Main; chance of PM/evening showers, with snow levels around 10K and an inch of accumulation possible up Top.
Mon 5/4 – Snowfall likely develops during the day and continues at times overnight into Tuesday. Snow levels 8000-8500 feet during the day, lowering to 7000 feet overnight. Accumulations 5 – 7” at Main, 7”+ up Top by Tuesday morning
Tue 5/5 – Generally light snowfall continues into the evening, with snow levels rising to near 8000-8500 feet during the afternoon/evening after starting out near 7000 feet during the morning. Accumulation 2 – 3” at Main, 3”+ up Top by Wednesday morning.
Forecast Summary:
Short Term (Days 1 – 4):
The current infrared satellite image (below) this afternoon shows high pressure situated across the Interior West, and a weak low-pressure system and fronts are positioned along the Washington and Oregon Coasts. Mammoth is enjoying a fair weather day with just some passing high clouds.
The weather system over the Pacific Northwest coast will move southward off the coast of California by Saturday afternoon (image below), which may kick off some late PM rain showers. It will become a cut-off low by Sunday and then slowly move inland on Monday while deepening slightly (two images below) before exiting southward on Wednesday (three images below).
When it moves inland on Monday, especially overnight Monday and into Tuesday, accumulating snowfall is likely. Wrap-around snowfall continues Tuesday as the low moves southeastward before ending Tuesday evening. There could be some rain/snow showers on Sunday afternoon/evening, too, but snow levels will likely be around 10,000 feet. Snow levels on Monday should start around 8,500 feet in the afternoon, then lower to 7K overnight into Tuesday.
The GFS (image below) and Canadian (two images below) are the wettest models of the bunch, and both show around 2” of liquid for the period. The ECM model has out half that amount at just under an inch (three images below), and the NBM has around 1 inch (four images below).
The ensemble mean of the GFS is closer to the NBM at around 1 inch of liquid (image below), and the ECM EPS (two images below) shows slightly less. Forecast leans toward an NBM/ECM blend with around 1 inch of liquid total and 7-10” for the event, with most of the snow falling Monday night.
That lines up well with the ECM snowfall forecast (image below), which shows around 8” of snowfall, while the GFS (two images below) would be a wonderful surprise at about 18” at Main, but not likely. Either way, there should be enough powder conditions on Tuesday and again on Wednesday morning, with temperatures rising quickly during the day on Wednesday.
Long Range (Days 5+):
The longer-range guidance suggests the powder party might be over, and next week’s event could very well be the last call for the season. The models are looking rather typical for mid to late spring, with the jet stream weakening and retreating northward toward the North Pole, as usual.
The GFS ensemble 6-10 day forecast (image below) shows a ridge of high pressure building into the state, bringing fair, typical spring weather and conditions. This pattern should last through the following weekend and into the next week, and spring conditions will prevail across the mountain.
Spring conditions will likely continue for the foreseeable future, with the GFS ensemble 11-15 day pattern (image below) showing the jet stream well to the north, into Washington/British Columbia, and a baggy trough southward into CA.
The ECM EPS is mostly similar, but has more ridging southward into CA and a weaker baggy trough over SoCa. Either way, it will result in dry weather and typical spring conditions for mid-May, with no signs of any more snowfall chances into Memorial Day weekend
If there is another late spring surprise, Snowman will have you covered, as this will be the last post for the 2025-26 season.
Enjoy the rest of spring and the upcoming summer, and hopefully the upcoming El Niño will come through for us big time next season. WG
