Powder Forecast – Friday March 28th, 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)
Sat 3/29 = trace
Sun 3/30 = 0 – 1”
Mon 3/31 = 1 – 2”
Tue 4/1 = 8 – 10” (H20 = 0.75” – 0.90”)
Wed 4/2 = 2 – 3”
Thu 4/3 = 0”
Fri 4/4 = 1 – 3”
Sat – Mon 4/5 – 4/7 = 1 – 3”
March Snowfall = 60”
March Forecast = ~61”
Detailed 4-day Snowfall Forecast:
Sat 3/29– No snowfall expected.
Sun 3/30– Light snowfall is expected at times during the day and overnight. Accumulations 1 – 2” at Main by Monday AM, ~3” up top
Mon 3/31– Snowfall, briefly heavy at times, is expected at times during the day, tapering off overnight. Accumulations 8 – 10” at Main by Tuesday AM, 10”+ up top
Tue 4/1– Snow showers, mostly afternoon/evening, ending overnight. Accumulations 2 – 3” at Main by Wednesday AM, ~3” up top
Forecast Summary:
Short Term (Days 1 – 4):
The current infrared satellite image (below) this afternoon shows a dry cold front moving into SoCal that is part of a lower low-pressure trough situated along the West Coast. A trailing low and sub-synoptic trough will move into NorCal this afternoon and evening before high pressure builds into the state briefly Saturday. There could be few light snow showers or flurries overnight, but no accumulation or only a trace is expected.
The next weather system moves into the state on Sunday and Monday (image below) and it will be far enough southward this time for meaningful snowfall in Mammoth. It will come in three waves with light snowfall on Sunday followed by heavier snowfall Monday and then a trailing low will produce one more round on Tuesday.
Model QPF for the storm is generally around an inch with the ECM (image below) and GFS (two images below) just under an inch. The Canadian (three images below) and the ECM EPS (four below) both have around 1.25” liquid.
It is a fairly deep upper-low, so the forecast follows the larger amounts and almost a foot of snowfall at Main over the 3-day period with most of the snow falling during the day Monday (riders of the storm day). Sunday could possibly be a dust on crust day with only an inch or two of snow expected.
Long Range (Days 5+):
The longer-range guidance has basically flipped from wet to not so wet over the past few days with the GFS model the last to get on board with the drier solution. Thus, the potential last big snowfall of the year highlighted in the last post probably is not going happen now with only a smaller storm favored instead.
Wednesday next week may be a mostly dry day before one last upper-level trough drops southward into the state from the Gulf of Alaska per the ECM model (image below) for light to moderate snowfall. It has the low lingering over the southern part of the state through the weekend (image below) that would keep temps winter-like and possibly some light snow showers.
The GFS ensembles are finally moving toward the ECM solution, although the mean 500-mb height forecast (image below) still shows a westerly jet stream into CA around mid-week that would be wetter versus the ECM. Forecast leans toward the ECM EPS that has performed better lately that has about 0.50” liquid for the end of next week. Thus, there could be enough for low-end powder conditions, best chance on Friday or Saturday.
The guidance then generally favors more typical spring weather returning over the following week under generally dry conditions or below normal precipitation (image below). The ECM EPS does suggest cooler weather returning over the next week, but the precipitation forecast shows mostly below normal (two images below). Unless there is a late season surprise, the last deeper powder day of the season may be next Monday and/or Tuesday. WG
