Powder Forecast — Tuesday April 25th, 2017
Ted Schlaepfer CCM —- Mammoth Mountain WeatherGuy
Other than a chance for rain showers at Main and snow showers up top Wednesday afternoon, dry weather is expected for the next week or longer with no signs of any significant precipitation and/or snowfall. Slightly cooler weather is expected Friday, then warmer weather with spring conditions on the entire mountain will start Saturday and continue through at least the middle part of next week before cooler weather is possible end of next week back to seasonably cool levels, but not winter-like. Seasonably cool temps with a chance for an infrequent storm is favored for the second and third weeks of May.
Next update Friday 4/28
Snowfall forecast are for the Sesame snow course (Main Lodge)
**Snowfall forecast confidence ranges from very low (1) to very high (5)
Wed 4/26 = 0”
Thu 4/27 = 0”
Fri 4/28 = 0”
Sat 4/29 = 0”
Sun 4/30 = 0”
Mon 5/1 = 0”
Tue 5/2 = 0”
Wed – Fri 5/3 – 5/5 = 0”
April Snowfall = 68”
April Forecast = 68”
Seasonal Snowfall = 619”
Seasonal Forecast = 625 – 635”
Detailed 5-day Snowfall Forecast:
Wed 4/26 through Sat 4/29 — No snowfall expected all days.
Satellite imagery (below) shows clouds associated with frontal system moving into the Pacific Northwest with CA on the southern edge of the jet stream flow. The weak storm currently off the Oregon coast will dig southward tomorrow through Nevada and the warm front will drag through CA during the day.
That will lead to an increase in wind on the mountain along with cloudiness by the afternoon with light rain showers possible at Main and snow showers up top with the snow levels around 9.5-10K. Maybe an inch could fall up top.
Another upper level low will take a track southward farther inland like a true inside slider Thursday and into Friday (image below) as models develop a deep trough in the mid-continent. That means slightly cooler temps with firmer snow up top by Friday and snow elsewhere slower to soften along with continued breezy to gusty northerly winds.
The numerical guidance is then in agreement that the ridge of high pressure currently well off the CA coast will nudge eastward into CA over the weekend (image below). Freezing levels will get above 12K by Sunday which means spring conditions everywhere on the mountain under plenty of sunshine and light winds. Pack the sunscreen.
These conditions are favored to hold through most of next week. The GFS ensemble along with the ECM operational model extended range forecast favor the ridge to move eastward by the following weekend for cooler weather as a weak trough sets up along the West Coast (image below). It doesn’t look strong enough for snowfall, but should cool temps back to seasonably cool levels.
The climate models, CFS and ECM version, are both favoring a weak trough under a split jet stream along the West Coast during the second and third weeks of May (images below). This is a progressive pattern and not a stagnant ridge of high pressure with storm system moving into the PacNW every couple of days of varying strength.
Whether enough energy moves southward into CA and Mammoth under this pattern is unknown at this time and not generally favored, but there is certainly a chance for an infrequent storm under this type of pattern. It does favor seasonably cool temps which means a slower snow-melt for most of May, particularly for the top of the mountain, but we will have to wait on any potential late season powder days. WG