Mammoth Mountain Weather Forecast – Tuesday November 7th, 2017

Powder Forecast – Tuesday November 7th, 2017

Ted Schlaepfer CCM  —- Mammoth Mountain WeatherGuy

Forecast Summary:

Mostly cloudy but dry tomorrow followed by a chance for flurries Opening Day along with gusty southwest winds.  Partly cloudy Friday, breezy and dry Friday followed by fair weather Saturday and into Sunday.  Clouds increase Sunday along with southwest winds leading to the chance for light snow next Monday and into Tuesday.  Dry weather is then expected for the rest of next week.  Longer range models suggest it will be dry through the 20th with just a slight chance for a storm last week of November, but no signs of any major storm pattern for Mammoth yet.

Next update Friday 11/10

Snowfall forecast are for the Sesame snow course (Main Lodge)

**Snowfall forecast confidence ranges from very low (1) to very high (5)

Wed 11/8 = 0”
Thu 11/9 = 0”
Fri 11/10 = 0”
Sat 11/11 = 0”
Sun 11/12 = 0”
Mon 11/13 = 0”
Tue 11/14 = 2 – 6”
Wed – Fri 11/15 – 17 = 0”

November Snowfall = 2”
November Forecast = 20 – 30”
Detailed 5-day Snowfall Forecast:

Wed 11/8 — No snowfall expected.

Thu 11/9 — Flurries possible during the day with gusty winds.  No accumulation expected.

Fri and Sat 11/10 & 11/11 — No snowfall expected both days.

Forecast Discussion:

Short Term:   

Satellite imagery (below) this afternoon shows a well-defined center of low pressure in the Gulf of Alaska and an associated frontal system just off the West Coast.   That low pressure system and front will move onto the coast tomorrow for increasing cloudiness along with increasing southwest winds.

Numerical guidance has now trended farther north with the passage of the low pressure system for Thursday (image below) with the core of the jet stream (purple arrow) staying well north of Mammoth into the northern Sierra.

All of the models keep precipitation (image below) north of Mammoth and generally north of Hwy 50 with dry conditions for Mammoth, although there is probably enough upslope flow for some flurries or light snow showers during the day, but no accumulation.  That strong upslope flow will also produce gusty southwest winds for Opening Day that may result in chair lift delays or even closings.   Not the best weather for the opener especially given that Chair 1 is rather sensitive to the southwest winds.

Dry and breezy weather continues Friday as a trailing weather system moves into NorCal.   Fair and calmer conditions are expected Saturday in the wake of the passage of the low pressure system and the return of a weak transitive high pressure ridge.

Southwest winds and clouds will probably increase again Sunday when another upper level low pressure system drops southward from the Gulf of Alaska.   The models, per the ECM below, move the upper level trough into CA around Monday next week.   Generally, the guidance takes this low pressure system a bit farther southward than the one for Thursday, but not a direct hit, and mostly just a brush job.

The GFS model is the wettest with around 0.75” of precipitation that might be good for around 6”+ of snow.   The ECM and Canadian models are not as wet and are showing only about a quarter inch of QPF or about 2-3” of snow. The current forecast favors the ECM ensemble mean QPF of about 0.35” or 3-4” of snow. If it ends up farther northward than currently projected like what happened with the Thursday storm did, then amounts could be less or even zero.

Long Range:

   The longer range models move another trough of low pressure into the PacNW toward the middle/end of next week as the storm track stays well north of Mammoth.   This is rather normal for mid-November as the PacNW usually sees lots of storminess late fall and early winter before the storm track shifts southward.

All the models then develop a high pressure ridge over CA (image below) by the end of next week and over the following weekend for fair and warmer weather.  The longer range ensembles then favor holding this pattern until at least the 20th of November or even longer with only a few ensembles showing any solutions favorable for any snowfall.

The longer range climate models are not bullish about any type of pattern that would produce good snowfall for Mammoth through the end of November.  The CFS model is showing generally normal precipitation over the last part of November and early December, so it might be awhile for a good storm.

That also means that there probably won’t be any good snowfall events before Thanksgiving weekend with any open runs probably confined to where they can blow man-made snow.   Thanksgiving is still over two weeks away, so there is always a chance that the models are wrong beyond 7-10 days about the overall atmospheric pattern.  Let’s hope so this time.  WG