Powder Forecast – Tuesday March 14th, 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.

Sesame Snow Course

**Snowfall forecast confidence ranges from very low (1) to very high (5)

Wed 3/15 = 20 – 22” (H20 = 3.00” – 3.25”)**3
Thu 3/16 = 0”
Fri 3/17 = 0”
Sat 3/18 = 1 – 3”
Sun 3/19 = 0 – 1”
Mon 3/20 = 1 – 2”
Tue 3/21 = 6 – 12”
Wed – Fri 3/22 – 3/24 = 10 – 20”

March Snowfall = 102”
March Forecast = 160 – 190”

Detailed 4-day Snowfall Forecast

Wed 3/15 – Chance for an afternoon snow shower, otherwise dry. No accumulation expected

Thu 3/16 – Chance for an afternoon snow shower, otherwise dry. No accumulation expected

Fri 3/17 – Chance for light snow Friday afternoon and night. Accumulations 1 – 3” by Saturday AM

Sat 3/18 –Chance for AM light snow, then tapering snow chances afternoon and night. Accumulations 0 –1” by Sunday AM

Forecast Summary:

Short Term (Days 1 – 4):

  The current infrared satellite image (below) this afternoon shows a potent storm system moving through CA with an Atmospheric River (AR) aimed into the central part of the state.  That AR will drag through Mammoth this evening with heavy snowfall for most of the mountain.  The bottom areas will probably remain rain until after sunset as it currently is a mix of snow and rain at Canyon.

  About 1.5” liquid has already fallen today resulting in about a foot of snowfall and another 1.50” liquid or slightly more is forecast for overnight and likely 10″ of snow. ECM model (image below) is showing about 3.5” liquid for the storm. Snow ratios should come down to around 6”:1” as the warmest air has arrived and should stay in cement ranges for the rest of the storm except for possibly the very tail end.

  Snowfall ends early tomorrow with only a chance for a light snow shower during the afternoon hours. Good chance for bluebird conditions when the lifts open tomorrow and winds tomorrow should be light.  Pretty good conditions for another powder day on the mountain.

  Dry weather is expected Thursday except for a chance for an afternoon/evening snow shower. The ECM model (image below) then moves a weak weather system through the central and southern part of the state Friday and into Saturday with light snowfall for Mammoth. The GFS model washes it out for just passing clouds.

  Regardless, the ECM is showing only light QPF (image below) and it likely would not result in enough snowfall for powder conditions.  But an inch or two certainly would keep conditions great over the weekend. The models move another weak system into the state Sunday for another chance for light snowfall with the Canadian model much stronger. Pack your chains as always.

Long Range (Days 5+)

  The longer-range guidance is still testing the sturdiest of powder enthusiasts to throw in the flag and say, enough is enough. It looks like we tied the record today for most precipitation in a season at Mammoth Pass surpassing the historical 1968-69 and 82-83 seasons.  And the new record will be hard to break as there is more on the way, possibly through the end of the month.

  The ECM model moves the next stronger storm into CA around Tuesday next week (image below) and that solution is well supported by the ensemble mean of the GFS (two images below) and EPS.  Snowfall should return by Monday night and continue at times into Wednesday.

  The ECM model is not as wet as the GFS model.  It has about 2.5” for Monday and Tuesday (images below) and not very much on Wednesday as it moves the trough farther east rather quickly. The Canadian is similar for Mon/Tue, but has over an inch more on Wednesday.

  The GFS model is the wettest as it is the only model that has an AR associated with the trough. It is forecasting about 10” for the Sunday through Friday period (image below) with most of the precipitation falling on Wednesday.  A few of the ECM ensembles have an AR, but most do not. Not only would that result in big precipitation difference, snow levels with the GFS would be high again.  We will have to wait and see how it plays out, but more snowfall is likely next week.

  The GFS ensemble keeps the long-wave trough anchored along the West Coast into the following weekend (image below) and the EPS is similar. The orientation of the jet is more northwest, so any storms should be colder versus recent AR events and likely originate from the Gulf of Alaska or north Pacific.

  The ECM EPS (image below) keeps a fairly similar pattern in place into the following week. So there is a chance we could cycle from warmer type storms now to colder type ones starting the last week of the month.

  The total precipitation from the ECM EPS (image below) is about 7” west of the Sierra crest. Another 4-5 feet of snowfall after today’s storm by the end of the month is not out of the question.  It the 12z run of the GFS is right, it will a lot more than that (two images below) with about 16” total liquid.  It has been a crazy season, anything goes at this point. WG