Powder Forecast – Tuesday, March 31st, 2026
Ted Schlaepfer CCM —- Mammoth Mountain WeatherGuy
No Update on Friday, April 3rd
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 4/1 = 5 – 8” (H20 = 0.65” – 1.00”)
Thu 4/2 = 2 – 3” (H20 = 0.25” – 0.35”)
Fri 4/3 = 1”
Sat 4/4 = 0”
Sun 4/5 = 0”
Mon 4/6 = 0”
Tue 4/7 = 0”
Wed – Fri 4/8 – 4/10 = 0 – 2”
March Snowfall = 1”
March Forecast = 1”
Detailed 4-day Snowfall Forecast:
Wed 4/1– Snowfall tapers off during the morning before increasing again during the afternoon and evening with continued light snowfall overnight. Accumulations 2 – 3” by Thursday AM, 3”+ up top.
Thu 4/2– Chance for light snowfall during the morning with dry weather returning by the afternoon. Accumulations ~1”.
Fri 4/3 and Sat 4/4 – No snowfall expected both days.
Forecast Summary:
Short Term (Days 1 – 4):
The current infrared satellite image (below) this afternoon shows a band of cloudiness/sub-tropical moisture streaming into central California and a weak low-pressure system just off the coast. Snowfall is now occurring on the mountain, and that weak system will keep snowfall ongoing overnight as it pushes inland.
Model guidance has now shifted to what was projected by the ensemble means of the models from the last post, with a range of around 0.65” liquid from the ECMWF (image below), half an inch from the Canadian (two images below), and about 0.75” from the GFS (three images below). The National Blend of Models (four images below) is the wettest at just over an inch of liquid. The forecast leans toward a blend of the ECMWF and NBM for about 5-8” of snowfall at Main by Wednesday morning and enough for powder conditions.
Another deeper upper-level low, currently pictured off the PacNW coast, will move southward into NorCal on Wednesday (image below) and pass through the Sierra by Thursday morning.
It will be just a bit too far northward for good dynamics/upslope orographic flow for Mammoth with the ECMWF (image below) and GFS (two images below) in agreement that any significant precipitation will stay well north of Mammoth. Both models are showing around a third of an inch of precipitation with its passage Wednesday afternoon and night, or about 2-3” of snowfall by Thursday morning. Should be enough for low-end powder conditions, especially up Top.
High pressure then builds back into the state on Friday and through the weekend, bringing a return to fair and dry weather. Temps should remain winter-like Friday and likely Saturday before warming back up to typical spring on Sunday.
Long Range (Days 5+):
The longer-range guidance looks typical for early spring, with chances for weak storms at times and nothing significant. Overall, the month of April is looking like average snowfall (~20”) and slightly above normal temperatures.
The next chance for a spring storm will be around the middle or end of next week. The GFS ensemble (image below) is showing a weak trough, and ECMWF has it as well. Most of the ensembles are dry, but a few are showing enough accumulation for powder conditions. The ECMWF EPS is mostly dry and shows about two tenths (see two images below), which may be enough for very low-end powder conditions.
Weak high pressure will probably build into the state over the following weekend with the next chance for a weak trough around mid-month. Overall, the ECM EPS (image below) is forecasting near to slightly below normal precipitation for April or about 20” of snowfall. WG
