Friday February 24th, 2017
Ted Schlaepfer CCM —- Mammoth Mountain WeatherGuy
Partly cloudy and seasonably cold weather continues through the upcoming weekend with only flurries expected until early Monday when a period of light and dry snowfall is possible with maybe up to 6” of total accumulation. A period of quiet and dry weather is then expected for the rest of next week and through the following weekend or longer. Next chance for any snowfall would be around March 10-11th with generally dry weather favored through mid-March. No clear signs of any storm cycles through the third week of March or longer.
Next update Tuesday 2/28
Snowfall forecast are for the Sesame snow course (Main Lodge)
**Snowfall forecast confidence ranges from very low (1) to very high (5)
Sat 2/25 = 0”
Sun 2/26 = 0 – 1”
Mon 2/27 = 2 – 4”
Tue 2/28 = 2 – 4”
Wed 3/1 = 0”
Thu 3/2 = 0”
Fri 3/3 = 0”
Sat – Mon 3/4 – 6 = 0”
February Snowfall = 162.5”
February Forecast = 165 – 170”
Seasonal Snowfall = 496.5”
Seasonal Forecast = 575 – 600”
Detailed 5-day Snowfall Forecast:
Sat 2/25 — No snowfall expected through the morning, then flurries possible during the afternoon and at night, no accumulation expected or maybe an inch by Sunday AM.
Sun 2/26 — Flurries possible early AM, then dry until late Sunday night when light snow is expected to begin. A few inches of fluffy accumulation possible by Monday AM.
Mon 2/27 — Light snow during the day, mostly AM, ending overnight. A few inches of fluffy accumulation possible by Tuesday AM, 6”+ up top
Tue 2/28 — No snowfall expected.
There is a nearly stationary area of low pressure in the central Pacific northwest of Hawaii with a strong and anomalous high pressure ridge building into the Gulf of Alaska that is all part of a Rex Block (image below). A high latitude and cold upper level low pressure system now positioned off the PacNW coast has moved around the building ridge and is currently tracking southward.
It the last update, the models were showing the cut-off in the Pacific either merging with the southerly tracking cold low pressure system or at least feeding needed moisture into the low that are defined by the lack of large PWs (precipitable water plumes) having originated in the Arctic.
The latest ECM model (image below) run shows that the low pressure systems will not be merging now with the current low off the PacNW taking a track into SoCal with the other low pressure system remaining separate and off the coast. There could be some flurries or light snow showers Saturday afternoon and night, but no significant snowfall expected with the only outcome continued seasonably cold temperatures.
A second and stronger high latitude trough will move southward on Sunday and Monday and that low will also not merge with the offshore low. That second and stronger low will move into the Sierra early Monday (image below) and there will be enough dynamics to squeeze out some snow from the limited moisture.
The ECM and Canadian are the most bullish about some light snowfall with the ECM showing about a third of an inch QPF total. But with snow ratios in the 20:1 range under the very cold air mass that could mean six inches of fluffy dry snowfall by midday Monday which might not be dust on crust considering the already soft snow conditions under the current cold temps.
Any snowfall ends by Tuesday morning with the models showing a high pressure ridge building into the West Coast by the middle part of next week (image below). That means the return of fair and dry weather.
The 12Z Friday run of the ECM model is showing the high pressure ridge to continue to build for the rest of next week and through the following weekend (image below). It suggests that temps will slowly rise back to seasonal normal levels by the end of the week and remain fairly steady or warm slightly through the first weekend of March.
The longer range ensembles are then favoring that ridge to generally hold firm for most of the following week before a weak trough may be able to move into the West Coast and CA again toward the end of that week (image below). So it looks like at least 10 days of dry weather in early March with that chance looking rather weak right now with any storm probably staying to the north of Mammoth.
The dry weather is generally favored to last through mid-March according to both the CFS and ECM climate models. The CFS model is showing below normal precipitation through the middle of March (image below) and the ECM is similar. The models even show dry weather beyond that too, but skill beyond 3 weeks is garbage and even a week three forecast has limited verification skill.
Overall, after a chance for some light and dry powder (but not deep) on Monday, there are no clear signs of any powder days through the middle of March or longer. Good news for the local residents who are currently buried, bad news for the powder hounds. WG