Powder Forecast –Tuesday March 3rd, 2020

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 3/4 = 0”
Thu 3/5 = 0”
Fri 3/6 = 0”
Sat 3/7 = 0”
Sun 3/8 = 2 – 3”
Mon 3/9 = 0 – 1”
Tue 3/10 = 0 – 6”
Wed – Fri 3/11 – 3/13 = 10 – 20”

March Snowfall = 9”
March Forecast = 50 – 70″

Detailed 4-day Snowfall Forecast:

Wed 3/4 through Fri 3/6—No snowfall expected all days.

Sat 3/7—Light snowfall is possible during the morning hours and into the evening hours before tapering off overnight.  Accumulations 2 – 3” by Sunday AM, 4” up top.

Forecast Summary:

Short Term (Days 1 – 4):

    Infrared satellite imagery (below) today shows strong high pressure situated in the eastern Pacific with the ridge having built eastward into the interior West and CA as well.

   The models keep the ridge in place through Thursday (image below) and the end result will be dry weather and seasonable temperatures under mostly sunny skies.   Winds should be light on Wednesday and only a little breezy Thursday.

  The ridge shifts eastward Friday as a trough of low pressure approaches the West Coast.  Southwest winds should increase during the day along with cloud cover.  The latest ECM run then splits the trough upon landfall Saturday morning (image below) and keeps most of the precipitation north of Mammoth.

   The GFS model is much weaker with the split and keeps it mostly together upon landfall.  That model has about 6” of snowfall (image below) Saturday and into Sunday.    The Canadian is closer to the ECM and the ECM ensemble is only showing very light amounts.  Current forecast is only favoring a couple or maybe three inches.   It should be a nice refresher.

Long Range (Days 5+):

   The longer range guidance is still mixed with the ECM model the most bullish on a favorable set-up for beneficial snowfall.   That model moves a closed upper-level low quickly southward to off the CA coast by next Monday (image below).   It develops decent moist southwest flow into the central part of the state and Mammoth that would result in a good quantity of base snow.

   However, the GFS model (image below) is farther off the coast with the upper low and the Canadian model is even farther westward.  Both models keep the low well off the coast into next Wednesday.  That would mean a short wave ridge would replace the moist southwest jet into the Sierra and that difference would add up to about 2” liquid or 15-20” of base snow according to the ECM model.

   The ECM model eventually moves the low inland around Wednesday (image below) or Thursday next week.  Its solution would mean nearly continuous snowfall Monday and into Thursday next week and at least a couple feet with snow levels around 6K.  That solution is decently supported by the ECM mean that is showing around 2” liquid Monday-Thursday next week.

   While I am not ready to buy into the ECM solution yet, there is good potential for at least some decent amounts of base snow by Wednesday or Thursday as cut-off low pressure systems are usually not handled well by the models.  Let’s hope we get lucky.

   The GFS does move a deep upper level trough into CA (image below) on the heels of that system by the end of the week and over the following weekend.  That could result in good snowfall as well.  However, the ECM is slower and farther northward while the Canadian still has the weakening cut-off over CA next Friday.   So any snowfall may hold off until the latter part of the weekend.

   The GFS ensemble keeps a weak trough along the West Coast through mid-month.  That could result in a continued pattern of at least weak storms or no long dry periods.    The ECM climate model then favors storminess to increase again over the last 10 days of the month.  The CFS is not as wet, but it is not dry either.  March is looking pretty good for powder days.  WG