Today I will spend a little more time on the atmospheric setup for this storm, because the other details haven't changed too much. I will update the timing and totals, providing specifics for each wave. But first let's dig into why we are finally going to enter another stormy pattern with several periods of snow. This post will be longer than normal, but there's a lot going on and it warrants a closer analysis. I will provide a very brief summary of each storm just below in bold, for those that want to skip the in depth analysis.

I wanted to thank Cody Townsend for the shout out on Instagram yesterday. It's wonderful to see skiers, riders, and powder chasers utilizing these forecasts. Follow me @lstone84 on Instagram to track and chase storms all Winter long! 

The first thing I look at is the pattern in the upper atmosphere. This dictates what happens down low where we live and ski/board, on the surface. This is where we can see patterns of troughs (storms) and ridges, where conditions are typically dry. For much of the Winter, when it was dry, there has been a ridge across Europe that is blocking storms. At other times, there was an upper level area of low pressure, but it was too far north or south of the Alps/Pryenees to produce much of an impact. 

Over the next ten days, a more favorable upper level pattern will develop. This will be a progressive pattern that ushers several storms through the region. Unfortunately, the storm track will be farther north than we would like, resulting in a warmer airmass over the Alps, especially for the third round of snow. For a large part of the Alps, the low elevation snowpack is dismal, and this next round of storms will only make the situation worse. I will dig deeper into the snow levels for that event in a future post. Winds will also be very strong with at least the first two rounds of snow, mainly out of the west and west-northwest. Gusts over 100 km are possible at upper elevations with the first storm. As far as the general timing goes, there will be three waves of precipitation during the following times. 

Storm #1: Wednesday morning - Thursday afternoon. Warm, deep, and windy. 15 - 60 cms from East to West.

Storm #2: Thursday night - Sunday afternoon. Slightly cooler temperatures overall, but gradual warming throughout the event. 20 cms - 1 m + from East to West.

Storm #3: Monday night - Friday morning. Lower confidence, but initially VERY warm, with a cold front arriving in time for potentially solid low density snow. 20 - 50 cms from East to West.

The timing for storms #2 and #3 is still subject to change, and I will fine tune those as we get closer. 

Below is a map of the upper level pattern. You ca see the three storms lined from Europe and continuing over the northeast Atlantic. 

In the GIF below, you can see the storms in motion, as the storms move across the Atlantic, into and across Europe.

So there is our upper level setup. Three areas of low pressure targeting Europe and the Alps, one after another during the next ten days. If you look closely, you can see a blue line fluctuating up and down in the GIF. This is a good indicator of temperatures, and with the line remaining north of the Alps for these storms, the coldest air will be stuck north of the Alps. 

Now that we have an understanding of the general setup, let's get into the details of these three storms. 

Storm #1

The first in the series of three storms should arrive Wednesday morning in the French/Swiss/northwestern Italian Alps, with light snow falling above ~1500m. Snow becomes heavy Wednesday evening and continues through Thursday morning, and then becoming more showery. Snow showers should taper off by midday on Thursday, with impressive snow totals, between 30-60 cms. At the highest elevations, where temperatures are much colder, totals could exceed 60 cms in the French Alps. Expect slightly lower totals, around 20-40 cms in the Swiss Alps and only up to 15 cms in the far western Austrian Alps for this first round of snow. Below is the European model snow forecast for round one.

Storm #2

The second period of snow should start after midnight Thursday night in the French/Swiss/northwestern Italian Alps, quickly becoming heavy before sunrise. Snow will fall moderately to heavily until Sunday evening/night, with even deeper totals than storm #1. The better news is that temperatures look a bit colder for storm #2, with snow levels, on Thursday night, dropping to around 900 m - 1200 m in the French Alps, a bit lower in Switzerland, and considerably lower in Austria, potentially down to 600m. After temperatures drop Thursday night, they will gradually rise through the duration of this round of snow.

As mentioned, this storm should pack a bigger punch than storm #1, and combined with the cooler temperatures, will result in impressive snow totals. The distribution of the deepest snow totals will be similar to the first storm, and by the time this one winds down on Sunday, expect more than 1 meter for a large part of the French Alps! In Switzerland, 0.5 m to 1 m looks likely. For Austria, the heaviest totals will again be focused in the far western part of the country, in Vorarlberg, with Tirol doing pretty well also. Vorarlberg should see 40-80 cms, and perhaps over a meter in isolated areas. Lesser amounts in the 30-60 cm range expects for Tirol, and decreasing totals farther east. 

At the time I'm writing this, storm #2 looks like the best one to chase. Temperatures will be a bit cooler, snow totals will be greater, and the winds look less strong as well. For most of this storm, the winds should generally be most severe in the French Alps, and become less intense as you move north/east. Considering all these factors, I would plan to ride in Switzerland on Saturday and Sunday, targeting resorts with sufficiently steep terrain below tree-line that has a history of being able to stay open during very intense snowfall. 

Below is the European model snow forecast for round two.

Storm #3

With the third in this series of snowstorms arriving around Monday evening/night, I am less confident about some of the details. For the temperature and snow level discussion for storm #3, I will be using quite a few "maybe's", "around's", "perhaps'", and "potentially's", to show the uncertainty surrounding the location and timing of the cold front.

The snow levels, unfortunately, do look higher at the onset of the storm, resulting in more rain. Snow levels will begin to climb around Sunday night as a warm front arrives, a bit ahead of the precipitation. In France and Switzerland, snow levels could rise as high as 2100 m, before staring to fall later Monday night. It won't get quite that warm in Austria, with snow levels peaking around 1900 m. The period of mid and upper elevation rain will be short, perhaps only 3 - 6 hours. At lower elevations the rain should stick around for longer, maybe 9 - 12 hours. On the plus side, once the cold front does arrive, there is still ample moisture to deliver solid low density snow totals and a right side up storm. These details could certainly change over the next six days, and I will provide an update before storm #3 arrives. The winds don't look quite as strong with storm #3 also. 

Snow totals for storm #3 look solid at this point, though I have less confidence in these numbers at the moment. We are looking at another bullseye over the French Alps, with slightly lower totals in Switzerland and in the northwestern Italian Alps. Expect lesser amounts in Austria once again, but potentially more evenly distributed across all of the Austrian Alps. 

The models don't agree too much on when the snow will wind down for storm #3, but it should taper off sometime between Thursday and Friday morning. I will update these numbers as we get closer, but this round of snow has the potential to drop 20 - 50 cms across the Alps, with the most in the French Alps and lesser as you move north and east. Below is an early guess from the European model for storm #3 snow totals. 

Wow. That was a lot. If you made it this far, you must love powder. In total, these three storms have the potentially to deliver a massive amount of snow at mid and upper elevations. Yes, the high snow levels and low elevation rain are a bummer, especially with he current snow pack down low, but there should be some really good pow days in this series of storms. We have a big range of 50 cms to 2m from all these storms combined, with significant variation both in elevation and east/west location. I am looking forward to seeing how the next ten days unfold. 

Since the short-term forecast went all the way out past mid month, I will keep this section short. After this series of storms ends, the models show the potential for additional storm systems. Right now, the pattern looks similar to that of the next 10 days, with perhaps more cold air overall. Sweet.

Thanks for reading the forecast.