Powder Forecast – Tuesday, April 23rd, 2024

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 4/24 = 0”
Thu 4/25 = 0 – 1”
Fri 4/26 = ~ 1”
Sat 4/27 = 1 – 2”
Sun 4/28 = 0”
Mon 4/29 = 0”
Tue 4/30 = 0”
Wed – Fri 5/1 – 5/3 = 0 – 2”

April Snowfall: 29”
April Forecast = 30 – 35”

Detailed 4-day Snowfall Forecast

Wed 4/24– A chance for rain/snow showers during the afternoon and evening, ending overnight.  Little or no accumulation is expected.

Thu 4/25– Dry during the morning, then light snowfall during the afternoon and evening. Up to an inch of accumulation is possible by Friday AM.

Fri 4/26– Light to briefly moderate snowfall develops around midday and lasts into the early evening before ending.  Accumulations 1 – 2” at Main, ~3” up top by Saturday AM.

Sat 4/27– No snowfall expected.

Forecast Summary:

Short Term (Days 1 – 4):

   The current infrared satellite image (below) today shows clouds across NorCal from a weak wave moving over a ridge parked across Nevada/Utah. 

There is also a weak low-pressure center west of SoCal that will move through that part of the state tomorrow and into Thursday and another low off the PacNW coast.

The low moving into SoCal may kick off some showers/thunderstorms tomorrow, but freezing levels should be 9K or higher.

  The one off the PacNW coast will move southward into the state on Thursday and Friday (image below) for a couple of rounds of light snowfall.

The first front will produce light snowfall on Thursday PM and evening with snow levels around 8-8500 feet. Another round of light to briefly moderate snowfall is expected Friday midday into Friday evening, with snow levels around 6500 feet.

  Model QPF for the event is not that impressive, with the GFS showing about 0.40” liquid (image below) for both days and the ECM model having about a third of an inch (two images below).  The first round on Thursday should be just dust on the crust, while the snowfall on Friday may add up to very low-end powder conditions by late Friday PM when the lifts close or Saturday morning.  Saturday will be a dry day as high pressure moves back into the state.

Long Range (Days 5+):

   The longer-range guidance has trended a bit more bullish about a chance for a more impactful spring storm and potential powder day during the first week of May, although it certainly is far from a slam dunk this time of year and that far out in the forecast time frame.

  The first half of next week should be dry, though. The ECM model does develop a trough along the West Coast early next week (image below) that will keep temperatures seasonable or seasonably cool. It then moves the trough southward into the state toward the end of next week (two images below). However, it will be a moisture-starved weather system, and the model is only forecasting very light amounts, not enough for powder conditions.

  The longer-range fantasy GFS ensemble suggests that an unseasonably deep longwave trough will develop along the West Coast over the following weekend (image below) and into next week. The GFS operational run this morning also produced a very deep cut-off low for early May around the same time frame (two images below).

  That GFS operational run also is forecasting fairly large liquid precipitation amounts (image below), with that storm at around 2” for Mammoth and almost 4” west of the Sierra crest. It has the snowfall falling over two separate periods with the latter one early that week producing the most snowfall and easily over a foot.

  Unfortunately, the ensemble means from the GFS and ECM EPS are not as bullish yet about a big spring storm. The ECM EPS only shows about a third of an inch of liquid (image below) for a 96-hour period, and the GFS ensemble (two images below) shows only a few inches of snowfall.

  It is still a long way out in forecast time, but history says that May snowfall dumps are possible.  Record May snowfall is 32” from 2019 and there were six other seasons in the historical record back to 1970 when two feet of snowfall occurred during May.  Every single one of those years except 2011 was fading El Nino years, just like this year. So, yeah, it could happen. WG