Powder Forecast – Tuesday April 1st, 2025
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)
Wed 4/2 = 5 – 8” (H2O = 0.40” – 0.60”)**3
Thu 4/3 = 1 – 2” (H2O = 0.10” – 0.15”)**3
Fri 4/4 = 0 – 1”
Sat 4/5 = 0”
Sun 4/6 = 0”
Mon 4/7 = 0”
Tue 4/8 = 0”
Wed – Fri 4/8 – 4/10 = 0”
April Snowfall = 0”
April Forecast = 10 – 20”
Detailed 4-day Snowfall Forecast:
Wed 4/2– Snow showers develop during the afternoon and last through evening before ending late evening. Accumulations 1 – 2” at Main, ~2” up top
Thu 4/3– Snow showers and/or flurries develop during the afternoon, ending early evening. Maybe an inch accumulation.
Fri 4/4 and Sat 4/5– No snowfall expected both days.
Forecast Summary:
Short Term (Days 1 – 4):
The current infrared satellite image (below) this afternoon shows the parent upper-level low-pressure system associated with the snowfall over the past couple of days moving southeastward into the central part of the state. It will then linger over the southern part of the state through Friday.
It will move through Mammoth this evening with snowfall tapering off and ending overnight with another 6”+ of fresh snowfall expected at Main since this morning. Model QPF for today shows almost half an inch per the ECM (image below) and GFS (two images below) with the National Blend of Models slightly wetter at around 0.50”. Snow levels will be around 4K today, so it will be the drier type of fluffy snowfall with snow ratios 12”:1” or greater.
A weak trailing upper-level short-wave will move into the Sierra Wednesday (image below) and will produce more snow showers during the afternoon and evening that could add up to an inch or two. Instability snow showers are possible Thursday afternoon, but only a trace or maybe an inch accumulation is only expected. GFS has about 0.25” for the latter part of the (two images below) while the ECM has a tenth or so (three images below).
The low-pressure system will start to move eastward Friday and snow showers should stop with fair and warmer weather forecast for the weekend. It will probably stay winter-like up top while the Ch.9/Ch.25 side of the mountain and other lower areas should see spring conditions by the afternoon, especially Sunday.
Long Range (Days 5+):
The longer-range guidance is favoring a transition back to spring next week with briefly cooler weather favored to return next weekend, but just a slight chance for light snowfall. Fairly typical spring weather likely returns over the next week with no clear signs of any late season storms that would produce powder conditions.
A weak weather system will move into NorCal around Monday next week (image below) and too far northward for any snowfall in Mammoth with just passing clouds. However, it will lead to an increase in westerly winds that should get the wind buff machine going on the upper part of the mountain.
Any wind buff up top will be short-lived as the guidance is favoring a moderately strong high pressure ridge to build into the state for the rest of next week (image below). That will result in spring conditions across the mountain.
The longer-range guidance is then favoring a long-wave trough to develop along the West Coast over the following weekend. The GEFS (image below) is deeper versus the ECM EPS, but is still too far northward with the trough and placement of the jet stream for any significant snowfall in Mammoth and both models are only forecasting maybe an inch or two of snowfall. There is also a chance it may shift farther southward as forecasts that far out are unreliable.
Fairly typical dry (image below) spring weather is then expected just after mid-month and through the Canyon/Eagle closing day weekend. Guidance is favoring a weak zonal jet into the West Coast for seasonable temperatures and breezy spring winds. It certainly could change, but right now, there are no signs of any late season surprises. WG
