Powder Forecast –Tuesday, April 2nd, 2019
Ted Schlaepfer CCM —- Mammoth Mountain WeatherGuy
Snowfall tapers off this evening and ends tonight with dry weather expected tomorrow and Thursday.
Snowfall chances increase during the day Friday with snow likely Friday night and Saturday morning with dry weather probably returning Sunday and Monday.
Next chance for light snow will be around Tuesday next week followed by another chance for snowfall end of the week or the following weekend.
Overall, powder conditions are expected tomorrow and again Saturday/Sunday with a chance for low-end powder mid-week next week.
No Update Friday, next update Tuesday 4/9
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 4/3 = 6 – 7” (H20 = 0.75” – 0.80”)**4
Thu 4/4 = 0”
Fri 4/5 = 0 – 1”
Sat 4/6 = 5 – 8” (H20 = 0.60” – 0.80”)**2
Sun 4/7 = 2 – 4” (H20 = 0.20” – 0.40”)**2
Mon 4/8 = 0”
Tue 4/9 = 0”
Wed – Fri 4/10– 4/12 = 0 – 6”
April Snowfall = 5”
April Forecast = 35 – 45”
Detailed 4-day Snowfall Forecast:
Wed 4/3 and Thu 4/4 —No snowfall both days except for a chance for light snowfall overnight Thursday into Friday. Light winds both days.
Fri 4/5 —Snowfall is possible by the afternoon and more likely at night. Gusty winds increase during the morning hours.
Sat 4/6 —Snowfall is possible during the morning before likely ending during the day. Gusty winds decrease by Saturday afternoon.
Satellite image below shows an upper level low pressure system moving slowly through the Sierra with moderate snowfall currently being observed in Mammoth. The upper low will swing eastward tonight and snowfall will end overnight.
About six inches of snowfall has fallen and the models have generally underestimated the QPF from the storm system. The GFS model is showing less than half an inch today (image below) and the ECM has around half an inch with current readings showing about 0.75”. Looks like enough already fell for powder conditions tomorrow on the mountain.
High pressure will briefly build into Mammoth in the wake of the system tomorrow and Thursday for fair and dry weather. Winds tomorrow should be light and temperatures seasonable by the afternoon. Slightly colder weather is expected Thursday with only a bit more breeze.
The latest ECM model run backed off significantly on the strength of the storm system for Friday and into Saturday. It now moves the strong upper level low (image below) into NorCal with Mammoth on the southern edge. The GFS model is similar or now even slightly stronger than the ECM, but still keeps the storm track mostly north of Mammoth.
Model QPF is up for the GFS, but down for the ECM model that is now showing less than an inch of liquid. The GFS model is not showing much more and is also around an inch (image below). So it should be enough for powder conditions, but it doesn’t look like deep powder or a large storm anymore.
Longer range guidance is suggesting a short-wave trough may move through CA around Tuesday next week (image below). Current solutions are not favoring a big storm, but a more typical spring storm system that could produce a few inches. It is still a week out and confidence low.
The ECM (image below) and GFS (two images below) then moves a deeper colder-type low pressure system southward into CA by the end of next week. This is similar to the set-up in February with a strong high pressure ridge building into the north Pacific and Alaska and forcing a deep trough southward into CA.
I am certainly skeptical about the ECM solution and whether that much energy can slip under the ridge mid-April with the GFS solution possibly being more realistic. It has happened before though as I remember skiing powder near Ch 9 mid-April with snow levels around 4500 feet.
The GFS ensemble moves the trough eastward over the following weekend (image below) and the ECM model is similar. It is still way too far out to know the details or even if it will happen, but it does represent another chance for powder conditions this month especially since the GFS is suggesting ridging thereafter (two image below).
The climate models are not favoring any big storm patterns through mid-April (image below) with a suggestion of more spring storms latter part of the month (two image below). If there is a late season surprise, this could be a year it happens. WG