Powder Forecast – Tuesday February 4th, 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 2/5 =20 – 25” (H20 = 2.50” – 3.00”)**3
Thu 2/6 = 0 – 1”
Fri 2/7 = 12 – 15” (H20 = 1.25” – 1.75”)**3
Sat 2/8 = 2 – 4” (H20 = 0.25” – 0.35”)**3
Sun 2/9 = 0”
Mon 2/10 = 0”
Tue 2/11 = 0”
Wed – Fri 2/12 – 2/15 = 10 – 20”
February Snowfall = 4”
February Forecast = 100 – 120”
Detailed 4-day Snowfall Forecast:
Wed 2/4 – Snowfall ends during the morning with dry weather the rest of the day. Accumulations 0 – 1” at Main by Thursday AM and 2” up top.
Thu 2/5 – Moderate to heavy snowfall develops around midday and continues at times overnight. Accumulations 12 – 15” at Main by Friday AM and 18” up top
Fri 2/6 – Snow showers continue through the afternoon before ending evening. Accumulations 2 – 4” at Main by Saturday AM and 6” up top.
Sat 2/7 – No snowfall expected.
Forecast Summary:
Short Term (Days 1 – 4):
The current infrared satellite image (below) this afternoon shows a strong weather system moving into central and northern CA with a moderate strength Atmospheric River (AR). The front will move southward overnight into Mammoth with heavy snowfall and strong winds that will continue into Wednesday morning before ending.
Model guidance is favoring at least two inches liquid per the ECM (image below), well over 2” liquid says the GFS (two images below), up to 3.5” from the National Blend of Models (three images below).
Forecast follows a wetter GFS with up to 3” liquid with the only real drawback is that it will move through rather quickly and only an 18-hour period of snowfall. It will also be a warmer storm with snow levels for most of the snowfall in the 7000-7500 foot range. Snow ratios will probably be 8”1” of Sierra cement and winds tonight will be very strong.
The next storm moves into Mammoth Thursday midday with the upper-level trough passage occurring on Friday morning (image below). The heaviest period of snowfall should be Thursday overnight and snow levels this time will be lower and around 6000-7000 feet. So it will likely be more Sierra cement type snowfall until Friday when snow levels lower to 4500 feet at the back end of the storm.
Model QPF is mostly in the 1.5”-2.0” liquid range with the ECM (image below) again showing lesser amounts versus the GFS model (two images below). The system certainly doesn’t have as much moisture as the current one, but it is dynamic, and the forecast follows closer to the GFS. That means more than a foot at Main is likely and possibly up to 20” of snowfall up top by Saturday morning. Friday will be a riders of the storm day.
Long Range (Days 5+):
The longer-range guidance is favoring a break from the storminess early next week before a favorable pattern hopefully returns by the end of next week. The pattern may stay somewhat active for the rest of the month with no prolonged dry period currently favored.
The guidance is saying the longwave trough will shift eastward over the weekend (image below) and through early next week. Mammoth will stay under weak northerly jet stream flow that will keep temperatures seasonable to seasonably cold and very good winter snow conditions.
The longer range model forecast is saying the next chance for a storm will be toward the end of next week. The ECM model (image below) moves a short-wave trough into CA from the Gulf of Alaska around Thursday/Friday next week. The GFS models is much weaker with this potential storm. That is evident in the QPF from the models with the GFS showing not much (two images below) while the ECM model (three images below) has around an inch liquid.
However, the ECM EPS is favoring a much deeper longwave trough developing across the West Coast end of next week (image below) that would support a stronger storm system. The precipitation forecast from that model is showing around 3” liquid (two images below) for the 3-day period that would result in two plus feet of snowfall. The GFS ensemble is much wetter than the deterministic run and has around an inch liquid for the period. The 18z GFS seems to be trending toward the ECM EPS and that lends confidence for more powder days possibly as early as Thursday with a better chance on Friday and/or Saturday.
Both long range ensemble systems suggest the next chance for snowfall would be early over the following week with the GFS ensemble (image below) showing a weak short-wave embedded in a west-northwest jet. The ECM is slightly more bullish and has well over an inch liquid (two images below) for the 11-15 day period and more potential powder days.
Overall, the ECM EPS is favoring almost 9” liquid for the 15 day period (image below) that would result in 70-80” of snowfall through mid-month. The longer range forecast keeps average to slightly above normal precipitation for the rest of the month (two images below) and into March. This all means that there is a good chance for a 100” month, fingers crossed. WG
