Powder Forecast – Tuesday April 18th, 2023
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)
Forecast cadence now switching to once per week on Tuesdays
Wed 4/19 = trace
Thu 4/20 = 0”
Fri 4/21 = 0”
Sat 4/22 = 0”
Sun 4/23 = 0”
Mon 4/24 = 0”
Tue 4/25= 0”
Wed – Mon 4/26 – 4/28 = 0”
April Snowfall = 3”
April Forecast = 3 – 5”
Detailed 4-day Snowfall Forecast
Wed 4/19 through Sat 4/22 – No snowfall expected all days.
Short Term (Days 1 – 4):
The current infrared satellite image (below) this afternoon shows continued clouds moving into the Sierra from a nearly stationary cold front. That front produced strong winds overnight and today, but only trace amounts of snowfall with snow showers ending this evening.
The trough will linger over CA through tomorrow with any precipitation staying well north of Mammoth. That means temperatures will stay winter-like and mostly in the 20s to mid-30s on the mountain. Winds on Wednesday though, will be much lighter and only be breezy during the afternoon, and will not result in lift holds.
The trough will then shift eastward on Thursday (image below) and high pressure will build into the weekend (two images below). The result will be fair and warmer weather each day with typical spring weather expected over the weekend including spring conditions on the mountain.
Long Range (Days 5+)
The longer-range guidance has now firmly stamped the idea that it will remain mostly dry for the rest of the month. There will be continued passages of short-wave troughs, so a big warm-up and spring melt is also not expected. A slow transition into spring.
The ECM model (image below) moves an inside slider-type trough east of CA and through the Great Basin early next week. That will produce cooler temperatures and breezy conditions on the mountain, but no snowfall.
It will re-enforce the development of a long-wave trough in the center of the country for the 6-10 day upper-level pattern (image below). CA and Mammoth will be on the western flank of the trough with a flat ridge off the anchored off the coast. This pattern would produce dry weather and mostly seasonable temperatures under northwest flow.
The next chance for any meaningful snowfall would be at the end of the month or early May per the GFS ensemble mean (image below) that has a rather deep trough for that time of year southward into CA. The ECM EPS is not as deep with only a baggy trough.
And that is reflected in the ECM EPS total period QPF (image below) that only has about 0.20” for the period with about 0.05” of that associated with the storm today. This has been a crazy season, and a late season storm would not be that surprising in case the GFS is onto something, right when everybody is finally set on spring. WG