Powder Forecast – Friday, March 14th, 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 3/15 = 8 – 10” (H20 = 0.65” – 0.75”)**4
Sun 3/16 = 0”
Mon 3/17 = 0 – 1”
Tue 3/18 = 10 – 14” (H20 = 1.00” – 1.50”)**2
Wed 3/19 = 0”
Thu 3/20 = 0 – 1”
Fri 3/21 = 0 – 2”
Sat – Mon 3/22 – 3/24 = 4 – 10”
March Snowfall = 53”
March Forecast = 85 – 100”
Detailed 4-day Snowfall Forecast:
Sat 3/15 and Sun 3/16– No snowfall expected on both days.
Mon 3/17 –Snowfall develops during the morning and continues during the day, heavy at times, tapering off evening and ending at night. Accumulations 6 – 9” at Main by Saturday AM, 10”+ up top
Tue 3/18 – No snowfall expected.
Forecast Summary:
Author Bio: Ted Schlaepfer, a Certified Consulting Meteorologist (CCM) with over 30 years of experience, has provided his popular Powder Forecast Posts here at Mammoth Snowman since the 2008/09 winter.
A lifelong weather enthusiast, Ted’s passion for snow and rain led him to skiing at age 5. He discovered Mammoth in 1979 and has been a regular visitor since the late 80s. His powder forecasts have helped countless skiers enjoy multiple powder days on Mammoth Mountain. Catch his fresh Powder Forecast Posts every Tuesday and Friday by 5 PM from November through April.
Short Term (Days 1 – 4):
The current infrared satellite image (below) this afternoon shows a storm system moving into the state, with the low center positioned near the California/Oregon border. This system will swing inland tonight, and snowfall should end this evening or overnight. It looks like another 8”+ of snowfall should fall at Main by the time it is over.
High pressure will build into the area this weekend with Sunday likely a bluebird morning and some lingering clouds Saturday when the top will likely open for more powder turns.
Clouds will increase Sunday afternoon and night ahead of the next trough (image below) and storm system for Monday. Snow should start just before dawn and become heavy at times by late morning/afternoon before snowfall tapers off during the evening and ends overnight. Riders of the storm, get ready to go.
Model QPF has increased a bit since the last post and the guidance is now favoring an inch liquid or more for the storm with the GFS model the wettest at around 1.75” (image below).
The ECM model (two images below) has just over an inch and the Canadian is forecasting around 1.25”. Forecast follows a blend of the ECM/GFS models and hopefully around a foot of snowfall at Main and 12”+ up top. Tuesday is expected to be a bluebird powder day.
Long Range (Days 5+):
The longer-range guidance has flipped back a bit to a better scenario for the last part of the month with any dry period now looking short-lived. There is always the usual uncertainty about how favorable the pattern may be, but we should be pleased with additional powder chances during the back end of the season.
The GFS ensemble mean moves a short-wave into NorCal on early Thursday (image below) and the latest ECM deterministic run is mostly similar and only a bit faster with the movement through the state. It is a rather weak system, and only light precipitation is expected across NorCal and mostly north of Mammoth.
A few ensemble members are farther southward with the storm and produce light snowfall in Mammoth Thursday. That is reflected in the light amounts in the ECM EPS (image below) that suggests an inch or two. Regardless of any snowfall, it should increase the westerly winds for great wind buff conditions in all the usual spots up top.
The guidance differs for the weekend with the GFS ensemble favoring a moderately deep trough along the West Coast with the jet stream southward into central CA (image below). The ECM model (two images below) is much weaker with the trough and much farther northward and this solution matches up well with the ECM EPS. The Canadian model is closer to the ECM solution.
The ECM EPS is fairly bullish about it staying northward with only very light amounts forecast (image below) while the GFS has enough for powder conditions. The differences probably have something to do with the MJO forecast as the GFS has it moving end of month into phase 6 while the ECM model has it emerging in the drier phase 7. The GFS has been doing better lately with that forecast.
Both model suites show a favorable pattern for more snowfall by the middle part of the following week. The ECM EPS develops a moderately deep longwave trough (image below) with decent southwest flow. The GFS ensemble (image below) has a slightly stronger jet stream, but under more zonal or westerly flow.
Both solutions would bring storms into CA with the ECM EPS potentially wetter. It is not showing a lot right now (image below) with under half an inch liquid, so hopefully that will continue to trend wetter, not just for the powder days, but also for the water as the eastern Sierra (image below) looks like it will end up near average on April 1, but Mammoth Pass is only 77% of normal. We probably need a bit more to make it until July 4th. WG
