The Powder Forecast
Powder Forecast –Friday December 31st, 2021
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)
Sat 1/1 = trace – 1”
Sun 1/2 = 0”
Mon 1/3 = 0”
Tue 1/4 = 0”
Wed 1/5 = 0”
Thu 1/6 = 0”
Fri 1/7 = 0’
Sat – Mon 1/8 – 1/10 = 0 – 6”
December Snowfall = 163”
December Forecast = 163”
Detailed 4-day Snowfall Forecast:
Sat 1/1 through Tue 1/4– No snowfall expected all days.
Short Term (Days 1 – 4):
The infrared satellite image (below) this afternoon shows one last upper-low and front moving southward through eastern CA and western Nevada and is responsible for the gusty winds today that has kept the top from opening. But those winds have got the wind buff machine going across the mountain and that is second best to powder. That weather system may also produce some light snow showers or flurries late this afternoon and evening, no significant accumulation expected.
High pressure (image below) will build into the state over the weekend resulting in fair and dry weather in addition to lighter winds. Thus, it looks like the top will finally open after being closed for more than a week.
Models then develop a deep closed low in the Gulf of Alaska southward into NorCal by Monday next week (image below). Models are now in agreement that it will not dig southward anymore and will quickly move eastward by the middle part of next week (two images below) with ridging building back into the state.
That is a big flip from the last post only three days ago that showed a very deep trough (image below) moving through CA resulting in another storm event. Thus, what was hoped to be another round of powder has now turned into a week long dry spell. There will be an increase in winds again early next week, so hopefully the wind buff machine can get going again.
Long Range (Days 5+):
The longer-range guidance has trended generally drier now through mid-January with no clear signs of the next powder day.
The ECM model (image below) and the other models as well do move a short wave trough into the West Coast and CA toward the end of next week. Latest GFS ensemble guidance (two images below) suggests that the jet will stay too far north for significant snowfall in Mammoth, but as we learned above, it is still a week out and the guidance may change.
Nonetheless, the GFS model is not showing a lot of precipitation in the 10-day period (image below) with only light amounts for next Friday. The ECM modle (two images below) is showing even less and is basically dry for the ten day period.
High pressure builds over the state over the following weekend (image below) for a return of fair weather. The longer range or fantasy guidance generally favors a shift in the teleconnection pattern heading into mid-month with the GFS mean (two images below) showing a deep trough from the Hudson Bay in Canada southward into the Eastern US and a ridge along the West Coast, or opposite of the current pattern.
The ECM EPS (image below) is similar and keeps this pattern in place through the end of the forecast period. That model is not showing much precipitation for Mammoth (two images below) over the 14-day period and basically not enough for any powder days.
The super duper longer range climate models, the ECM in particular, keep the dry pattern ongoing through the 21-day period (image below). That model does slowly bring back storminess toward the end of the month and into early February in the 21-28 day and 28-35 day periods (images below), but nothing really significant.
Overall, the next chance for a powder day will be the end of next week, but it is low confidence that it will pan out. After that, it might not be until the second half of January. The wildcard is the MJO as the models all have different solutions for its evolution over the next few weeks. If it loops back into phase 6 and then back into 7 toward the end of January and the AO stays strongly positive, then we could have a repeat of the second half of December. That is a nice New Years wish. Happy New Year. WG