Powder Forecast – Tuesday February 18th, 2025
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)
Wed 2/19 = 0”
Thu 2/20 = 0”
Fri 2/21 = 0”
Sat 2/22 = 0”
Sun 2/23 = 0”
Mon 2/24 = 0”
Tue 2/25 = 0”
Wed – Fri 2/26 – 2/28 = 0 – 2”
February Snowfall = 74”
February Forecast = 74” – 76”
Detailed 4-day Snowfall Forecast:
Wed 2/19– A chance for flurries during the day, otherwise, dry and breezy/gusty.
Thu 2/20 through Sat 2/22– No snowfall expected all days.
Forecast Summary:
Short Term (Days 1 – 4):
The current infrared satellite image (below) this afternoon shows a lot of cloudiness associated with a weather system off the West Coast that is curving clockwise around a high pressure ridge centered over CA today.
That weather system will move through NorCal on Wednesday (image below) and will be too far northward for any precipitation in Mammoth other than flurries. It should increase the westerly winds though, for wind buff conditions on the upper half of the mountain.
High pressure (image below) will then build into the state in the wake of its passage for more fair and dry weather. The ridge may build strong enough for temperatures to get warm enough for spring conditions on the lower part of the mountain by Friday/Saturday, primarily the Ch.25/9 side of the hill.
Long Range (Days 5+):
The longer-range guidance is saying that a mostly dry weather pattern will probably continue for the rest of February with just a slight chance that there could be a weak storm on the last day of the month or very early March. A change back to a wetter pattern has now been pushed back into the second week of March.
The fairly strong high-pressure ridge is forecast remain in place through the middle part of next week for little change in the weather pattern. A cut-off low pressure system is forecast by the models to approach the coast by the end of next week with the GFS ensemble opening it up as a flat wave over SoCal end of the week.
The 12z run of the ECM is different and moves the cut-off into Central California next Friday (image below) followed by another one on Sunday March 1st (two images below). The model has about an inch total (three images below) for the weekend from both systems that would be enough for powder conditions. Current forecast keeps it at slight chance levels as the ECM EPS is closer to the GFS ensemble that is mostly dry (~tenth of an inch liquid).
The general idea by the models now is it will remain mostly dry through the first part of March (image below) before a change to a more favorable pattern could occur over the second week of the month. I am still not completely convinced that it will remain dry in early March if the MJO gets into phase 2 by the end of the month.
Rossby wave interference is messing with the forecast predictions for the next week or so before the CPC says it will resume a more normal path into the Indian Ocean or phase 2 later at the end of February. Says the CPC “Should the MJO remain coherent over the Indian Ocean, a potential late winter extratropical response features a retrograding longwave trough over North America, signaling the return of warmer temperatures over the eastern U.S. with more enhanced onshore flow over western North America”. More enhanced onshore flow means storms for California again.
Both the GFS extended forecast (image below) and the ECM EPS long range (two image below) are showing at least average precipitation for the second week of March. Good, but not great. The CFS model is showing over an inch liquid for that time frame too (three images below). So, it certainly could be enough for powder conditions, we will have to keep our fingers crossed for bigger storms. WG
