Powder Forecast — Friday April 19th, 2017
Ted Schlaepfer CCM —- Mammoth Mountain WeatherGuy
Other than a chance for a late afternoon shower/thunderstorm starting Saturday and each afternoon through next Thursday, dry weather is expected during operations with no snowfall expected for the rest of May and probably season. Generally spring conditions is expected for the entire forecast period and probably end of month with no signs of seasonably cool weather until possibly early June. Seasonably cool weather with just a slight chance for a freak storm is then expected through early June before warmer weather is possible second week of June.
Next update Friday 5/26
Snowfall forecast are for the Sesame snow course (Main Lodge)
**Snowfall forecast confidence ranges from very low (1) to very high (5)
Sat 5/20 = 0”
Sun 5/21 = 0”
Mon 5/22 = 0”
Tue 5/23 = 0”
Wed 5/24 = 0”
Thu 5/25 = 0”
Fri 5/26 = 0”
Sat – Mon 5/27 – 5/29 = 0”
May Snowfall = 8”
May Forecast = 8”
Seasonal Snowfall = 627”
Seasonal Forecast = 627”
Detailed 5-day Snowfall Forecast:
Sat 5/20 – Tue 5/23 — No snowfall expected all days.
Satellite imagery (below) shows a high pressure ridge is positioned off the California coast with a weak short wave riding over the top of the ridge into British Columbia. That short wave will move southward as an inside slider into Utah over the weekend with the only real affect for Mammoth will be to keep temperatures relatively flat or only slightly warmer by Sunday plus introducing a chance for a late afternoon shower/thunderstorm.
The ridge (image below) is then forecast by the models to move farther eastward toward the coast on Monday where it will hold steady through the middle part of next week for further warming through mid-week with freezing levels getting up to 13K and temps up top around 50 F by Tuesday and next Wednesday.
The ECM (image below) weakens the ridge slightly toward the end of next week for only slightly cooler weather and continued spring conditions on the hill. The SW flow may inhibit thunderstorm formations for a few days.
The ECM (image below) model then redevelops the ridge along the West Coast over Memorial Day Holiday weekend with the stronger part of the ridge forming north of CA and in British Columbia with a weaker high pressure area over CA. Nonetheless, it means warmer weather again over the weekend with the GFS model saying temps up top could get into the mid-50s by Memorial Day.
That pattern should hold until early June with the longer range GFS ensemble (image below) is favoring the formation of a weak low pressure trough along the West Coast and CA. That would mean cooler weather, but still spring conditions on the mountain. The trough doesn’t look deep enough to support a storm right now with just a very slight chance that a freak storm could move into Mammoth under this scenario.
The GFS ensemble mean (image below) basically keeps the same pattern going through the first week of June. The CFS and ECM climate models are in general agreement. While there could be a freak storm like mentioned above, the likely scenario would be cooler temps and breezy or windy conditions at times.
Both the CFS and ECM climate models are then suggesting that a period of warmer than normal weather (image below) could develop over the second week of June for more spring or even summer type conditions. Overall, all the numerical guidance is suggesting a long stretch of spring weather continues through the end of the month with no signs of any more snowfall. The last update of the season is next Friday. WG