Powder Forecast – Tuesday, April 28th, 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)
Wed 4/29 = 0”
Thu 4/30 = 0”
Fri 5/1 = 0”
Sat 5/2 = 0”
Sun 5/3 = 0”
Mon 5/4 = 0”
Tue 5/5 = 3 – 6”
Wed – Fri 5/6 – 5/8 = 0 – 1”
April Snowfall = 47”
April Forecast = 47”
Detailed 4-day Snowfall Forecast:
Wed 4/29 through Sat 5/2 – No snowfall expected all days.
Forecast Summary:
Short Term (Days 1 – 4):
The current infrared satellite image (below) this afternoon shows clouds building over the Sierra as a very weak upper-level low moves eastward through the Sierra, initiating showers and thunderstorms. Snow levels will be around 9,000 feet; not expecting any meaningful accumulation.
High pressure off the coast will slowly move into the state over the next few days, resulting in fair, warmer temperatures returning to seasonable ranges and spring on the mountain That will last until Saturday, when the models are favoring another low-pressure system (image below) to drop southward from the Pacific Northwest to off the California coast, resulting in cooler temperatures and probably an increase in westerly winds, but no precipitation yet.
Long Range (Days 5+):
The longer-range guidance indicates the semi-active mid-spring pattern will continue through mid-week next week, followed by another slight chance of unsettled weather over the following week. The system next week may bring enough snow for powder conditions, and that may be the last call for the season, as it is getting late.
The guidance is mostly in agreement that the upper-level low will become quasi-stationary off the CA coast on Monday before slightly deepening and moving ashore Monday night or early Tuesday (image below). It will probably be deep enough to produce stratiform precipitation (i.e., a cold front) by Monday night and cold enough for snow levels to get down to near 6000 feet by Tuesday morning.
Amounts forecast by the models are generally in the half-inch range, with the latest ECM run showing about 0.65” (image below) and the GFS similar (two images below). The GFS seems to indicate slightly wetter conditions (three images below) and may be on the high side.
With the event still about six days out, the forecast leans toward the ECM EPS, which shows a bit more than half an inch of liquid (image below) or 3-6 inches of snowfall. The 12z EC run shows about 6 inches of snowfall for Monday night and early Tuesday (two images below), which is probably the best-case scenario. It should be enough for at least low-end powder conditions.
High pressure builds back into the state for the rest of next week and through the following weekend. The GFS model moves another low into NorCal early the following week (image below), which is probably too far north for snow in Mammoth. That solution is not currently well supported by the GFS ensemble mean. The ECM keeps a flat ridge in place during the same period, supporting continued fair/dry weather.
The fantasy range GFS ensemble keeps a weak trough along the West Coast and southward into CA (image below), which would mean a continued chance of a weak low-pressure system moving into CA. The ECM S keeps a flat ridge in place, but a few ensembles have a low-pressure system over CA, and the back-end precipitation forecast shows light amounts (two images below). It might not be enough for powder conditions; snow levels will be too high with just showers or thunderstorms from a cut-off low. The party is almost over. WG
