Powder Forecast – Tuesday, January 20th, 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 1/21 = 0”
Thu 1/22 = 0”
Fri 1/23 = 0”
Sat 1/24 = 0 – 1”
Sun 1/25 = 0”
Mon 1/26 = 0”
Tue 1/27 = 0”
Wed – Fri 1/28 – 1/30 = 0 – 3”
January Snowfall = 43”
January Forecast = 45 – 50”
Detailed 4-day Snowfall Forecast:
Wed 1/21 and Thu 1/22 – No snowfall expected both days except for a slight chance for flurries or light snow showers Thursday afternoon/evening above 8500 feet No accumulation expected.
Fri 1/23 – Dry during the day, then a chance for light snowfall late afternoon and evening Accumulations 0 – 1” at Main.
Sat 1/24 – No snowfall expected.
Forecast Summary:
Short Term (Days 1 – 4):
The current infrared satellite image (below) this afternoon shows weak high pressure is over California with a low-pressure system off the coast spitting lots of middle and high clouds over the state Temperatures are still mild for January with 30s up top and 40s across most of the mountain and around 50 at Eagle.
The low-pressure system will drift southward over the next few days and should be positioned off the Baja coast on Friday (image below). A weak short-wave will also move southward on the back side of the ridge through the Great Basin in Nevada and into the Southwest.
That short-wave may ingest enough moisture during its Friday afternoon passage, leading to light snow showers into the evening. Not much, if any, accumulation is expected, though the latest ECM forecast shows only trace amounts of liquid for Mammoth (image below). Dry and sunny weather returns Saturday.
Long Range (Days 5+):
The longer-range guidance shows the prolonged dry spell mostly lasting through next week and almost to the end of the month, except for a chance for light snowfall around Wednesday. The fantasy period has unfortunately trended drier now into mid-February, with the overall teleconnection pattern favoring more cold for the East, which usually means dry for us.
High pressure rebuilds through early next week (image below) for more fair and dry weather. The ECM model then moves a weak trough toward the West Coast around the middle part of next week, with Central CA on the southern boundary of the jet stream. The GFS model is much weaker.
The ECM shows most of the precipitation north of Mammoth (image below), while the GFS is completely dry across most of the state (two images below). Any snowfall per the ECM would be very light, and snow levels would be rather high, maybe above 8500 feet. Not expecting enough for powder conditions.
The ECM then sets up southwest flow into CA during the end of the month and first part of February and moves decently strong short-wave into CA over that first weekend (image below) The ECM EPS (two images below) has a trough along the West coast and the jet stream southward into CA, but it is much weaker with the flow and farther northward The GFS ensemble is even weaker with this feather.
As a result, the ECM deterministic run from this morning is the wettest (image below) at a few inches liquid, the ECM EPS not nearly as wet (two images below) at just over an inch, and the GFS Ensemble (three images below) showing about half the amount of the ECM EPS Even if the ECM is right, this could be a scenario with high snow levels again Fingers crossed that model runs trend more favorable.
Bigger picture teleconnection pattern has now become not so favorable for storminess in CA through early to middle February The SPV forecast has changed since last week and the ECM model is now favoring the vortex to weaken (image below) through mid-February and stay at neutral strengths into March It even has many members showing a major disruption of the vortex and Sudden Stratospheric Warming Event (SSW).
With the MJO forecast to remain in phase 7/8 (image below) through the end of the month, that will favor a trough and cold conditions for the Midwest and East through early/mid February and high pressure on the West Coast. That is what the models are showing with dry conditions for CA (images below) through the first part of next month.
If the MJO does progress into phase 2/3 by the middle/end of February as suggested by the ECM, then it may produce a favorable response, basically opposite of what occurs in phase 7/8 interacting with the SPV Looking at the SPV/MJO relationship chart below, this set-up would represent scenarios (c) and (d) that favor a negative PNA pattern Scenario (d) of a weak SPV and MJO in phase 2/3 is wetter with a zonal flow into CA (base snow) while pattern (c) supports colder type storms dropping southward from the Gulf of Alaska (dry powder) Both scenarios produce powder days WG
