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Snow in September

There will be two interesting weather events this week.

First, a surge of moisture will bring 1-3 inches of rain to southern California, Nevada, Arizona, southern Utah, and Colorado. Many of these areas need the moisture, so aside from flooding concerns, this is a good thing.

Second, and likely more interesting to snow lovers, a surge of cold air and snow will move south from Canada during the middle and end of the week.

The cold air will start the week in Alberta and will then move south to Montana on Tuesday, Wyoming on Wednesday, and Colorado on Thursday. Notice in the images below that the coldest air will stay east of the mountains, so the east side of the continental divide and the plains will feel the coolest readings.

snow forecast

Forecast temperature difference from average. Source: Weatherbell.com

This airmass will be cold and somewhat moist. This means snow for areas along and east of the continental divide, with the best accumulations likely to fall in Alberta Canada, Montana, and Wyoming. The eastern foothills and plains of Colorado could also see a few flakes Thursday night into Friday ... maybe.

snow forecast

Snow forecast for 24 hour periods from Monday through Friday. Source: Weatherbell.com

For most of the rest of the month, the long-range forecasts show the coldest air staying east of the mountains, similar to the path of the cold air above. While this may be disappointing, I'd rather have this pattern occur now and hope for a switch to a more western storm track when ski season cranks up in another two months.

JOEL GRATZ

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Infographic: Epic Pass vs Mountain Collective

[Update 9/15/2014: Vail Resorts bought Park City Mountain Resort and has added it to the Epic Pass for the 2014-2015 season. The graphic below does not reflect this late addition, but you can find an updated graphic here.]

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In the 1990s and early 2000s, many large US resorts sold season passes for well over $1,000. However, during the last five to ten years, the multi-resort pass has come into vogue. This is a great deal for skiers and riders who can enjoy multiple mountains for well under $1,000. For us at OpenSnow.com, we like this because you can chase powder instead of being locked in to one mountain!

There are many multi-resort passes, and two of the most prominent are the Epic Pass by Vail Resorts ($749), and the Mountain Collective Pass spearheaded by Aspen ($389).

Below is a pretty cool info graphic detailing these two passes. Enjoy, and please leave your thoughts and questions about multi-resort passes in the comments below!

Epic Pass vs Mountain Collective

Epic Pass vs Mountain Collective

Epic Pass vs Mountain Collective

Epic Pass vs Mountain Collective

Epic Pass vs Mountain Collective

Epic Pass vs Mountain Collective

Epic Pass vs Mountain Collective

Epic Pass vs Mountain Collective

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Where did the snow fall last season 2013-2014?

Where did the snow fall last season 2013-2014?

While we’ve been busily looking ahead toward next season (El Nino, Other Models, Farmer’s Almanac), we should also take a moment to remember last season.

Tony Crocker has a summary of the top resorts here, and below I summarized the season in visual form.

But before getting to the maps, I wanted to share two quick nuggets about last season that are at the top of my mind:

- In February 2014, Jackson Hole recorded snow on all but three days of the month (25 of 28 days). This snowfall totaled 143 inches or 11.9 feet.

- On 14 consecutive days between January 29 and February 11, 2014, Monarch Mountain in Colorado measured snow each day for a total of 123 inches or 10.25 feet.

Ok, now on to the maps:

winter snow ski conditions

Each map shows how things were compared to average. For temperatures, the eastern half of North America was cold while the west coast was warmer than average. For snowfall, the northern Rockies and mid-Atlantic were well above average. Source: NOAA

 

winter snow ski conditions

The coldest air was generally focused on the central and eastern part of the US while the southwest saw above-average temperatures for most of the winter. Source: NOAA

 

winter snow ski conditions

The mid-Atlantic and southeast saw above average snow/ice/rain in December, while February and March dumped well above-average snowfall on the northwest and northern Rockies. Source: NOAA

I like looking at the season in monthly chunks because it can show the timing of great (or bad) conditions even if the season as a whole was the opposite.

JOEL GRATZ

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Should we trust the Farmer's Almanac

Instead of blindly trusting (or not trusting) the Farmer’s Almanac winter forecasts, shouldn’t we first look back and see how they performed last year? At the very least this will help us know if they have a track record of accuracy or a track record of baloney.

Before getting into the graphics, one quick note. During this analysis, I found out that there is not one but two Farmer’s Almanacs. The “Old Farmer’s Almanac” was started in 1792 while the “Farmer’s Almanac” begin publishing in 1818. In the spirit of completeness, let’s look at how both of them faired last season.

Now to the maps! 

First, here are the forecasts from both Almanacs for the 2013-2014 winter compared to the actual temperatures recorded between November 2013 and March 2014.

farmers almanac winter forecast accuracy

Comparison of the forecast temperatures vs actual temperatures during the 2013-2014 winter. I placed a red X where the forecast was wrong and a green check mark where the forecast was correct.

The Farmers’ Almanac (top image) is relatively easy to verify since it breaks up the US into simple regions. They were incorrect across most of the west where they predicted cool temperatures while most locations were warmer than average. However, they did a pretty good job of predicting temperatures in the east.

The Old Farmer’s Almanac forecast map (bottom image) is like a smorgasbord, so it’s hard to find any patterns of right and wrong. They hit the temperatures correctly in some spots, but missed badly in others, like the northwest and over Texas.

Overall, neither Almanac offered consistently accurate temperature predictions last winter for the US. There are about the same number of red X’s and green check marks on each map.

Now, here are the forecasts from both Almanacs for precipitation (snow) last winter.

farmers almanac winter forecast accuracy

Comparison of the forecast precipitation vs actual snow/rain during the 2013-2014 winter. I placed a red X where the forecast was wrong and a green check mark where the forecast was correct.

Both Almanacs were wrong about California as it was very dry compared to forecasts of “snowy” and “near-normal precipitation”. In the east, both Almanacs did a pretty good job of predicting a snowy winter, but both missed the dry weather in the midwest and parts of the west.

Overall, neither Almanac offered consistently accurate precipitation predictions last winter for the US, and missing the continued drought in California is a glaring error.

In Canada, last winter’s temperatures were very cold over the eastern 2/3rds of the country and precipitation was about average for most areas.. The Farmer’s Almanac was accurate in predicting cold temperatures across the east while the Old Farmer’s Almanac was wrong about temperatures as it predicted above-average readings for the eastern part of the country. And neither Almanac was correct about snowfall. Whoops!

Here’s one more look-back before seeing what the Almanacs say about this season.

During this summer (June-August, 2014), both Almanacs predicted very hot weather for most of the US, and this was wrong as most locations have seen close to average temperatures with the central part of the country coming in a bit cooler than normal. Again, not a good forecast.

So what does all of this mean?

Since I see no track record of accuracy from the forecasts produced by the Farmers’ Almanac and the Old Farmer’s Almanac, I have zero confidence in their forecasts for the upcoming winter. 

farmers almanac winter forecast accuracy

Farmers’ Almanac forecasts for the upcoming winter (US and Canada).

If you like these types of maps and holding weather organizations accountable for their long-range predictions, check out meteorologist Jan Null’s website (links on middle-right of the page). He presents many historical forecasts from the Old Farmer’s Almanac and compares them with the weather that actually occurred.

Thanks for reading and for not putting too much faith in seasonal outlooks! We’re only two months away from tossing any seasonal forecasts to the side and focusing on the consistently accurate forecasts inside of 5 days.

JOEL GRATZ

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Another snow forecast for the 2014-2015 winter

For the record, I do not like long-range seasonal forecasts because they're usually not accurate. For proof, see the end of this post.

When a forecast is not accurate, you can't use it to plan, so it's not very helpful. This is why I like to wait until 7-10 days before a storm to estimate the general timing and location of a storm's snowfall, then refine the forecast until 2-3 days before the powder day, because that's when the forecasts become much more accurate.

That said, it's late August and we're a few months away from ski season, so we might as well look at the long range forecasts, mostly for entertainment value.

To start, there will be an El Nino this winter. For more about El Nino and what it might mean for snowfall over the next 6 months, read this article that I wrote last week.

While El Nino is a major factor that will determine snowfall patterns this winter, long-range weather models take into account many other variables when making 3-9 month forecasts. So let's look at what some of these long-range models say will happen between December and February.

Since we know that long-range forecasts aren't that reliable, forecasters try to stay away from looking at just one model's forecast and instead take an average of many models. This "ensemble" approach to forecasting can be more accurate than putting all of your forecasting eggs in one model basket.

So, without further ado, here's the winter forecast from an ensemble (group) of models that were made in the US, and another ensemble of models from other countries.

winter snow forecast

In general, the model ensembles show a similar forecast with snowy weather in the southwest, dry weather in the northwest, and snowy/rainy weather in the southeast. The model groupings differ for the northeast, however. 

These forecasts look rather credible to me because they are similar to how El Nino generally impacts snowfall across the country.

However, remember that these ensembles are just averages of many models. It's also useful to see the forecast from each individual model. If the individual model forecasts are similar to one another, we have more confidence in the overall forecast. But if they've very different, than averaging together a wide variety of forecasts can provide a false sense of certainty and confidence.

So, what do the seven individual forecasts that make up the US ensemble look like?

winter snow forecast

All of the models show average to above average snowfall (green colors) for various parts of the southwest, so that's a pretty good bet.

Five of the 7 models (71%) show below-average snowfall for the northwest, so that's also a pretty good bet but definitely not a certainty.

Four of the seven models (57%) show above average snowfall for Tahoe, while three of the seven show below average snowfall. In other words, "We don't know!"

For Utah and Colorado, four of the seven models show this area as being on the edge of below-average snowfall, while other models show no preference for above or below average snow. So again, "We don't know!"

And in New England, the models are about split between below average, average, and above average snowfall. A roll of the dice.

Whether you like these forecasts or not, you may be wondering, "Why should I trust these models anyway?" That's a good question, and one that too many forecasters ignore.

One way to assess the trustworthiness of the models is to compare their forecasts with the snowfall patterns that usually result during an El Nino year. If the patterns match the models, confidence in the models increases. If the patterns don't match, then we're left scratching our heads and should likely put lower confidence in any long-term forecast. For the upcoming winter, these model forecasts generally do match snow patterns during an El Nino, so my confidence is decent.

Another way to assess the models is by looking back in time to understand the accuracy of their past forecasts. So let's do that.

Here is the US model ensemble forecast for last winter. Specifically, the forecast was made in August 2013 and covers December 2013, January 2014, and February 2014. The bottom image shows the actual precipitation during this time.

winter snow forecast

The result of the forecast? The average of the US models provided a very bad forecast.

It incorrectly forecasted above average snow in the northwest and Tahoe while snowfall was below average.

It correctly forecasted the above average snow around Montana, Wyoming, and northwest Colorado, but was incorrect for the southeast and mid-Atlantic where it forecasted below-average precipitation while in actuality the area was hit with heavy snow.

Moving on, did the International model ensemble do a better job?

winter snow forecast

Yes, the international model ensemble was a bit more accurate, but far from perfect.

It hinted at below average precipitation along the west coast, but wasn't nearly bold enough to forecast the dryness that actually transpired.

And it also showed above average precipitation in the eastern US, but the location was wrong by ~400 miles as the heavier precipitation was along and east of the Appalachian mountains, not in the Mississippi River valley. Four hundred miles might not seems like a big distance for a model that covers the entire globe, but it's a big deal to a ski area that is only a couple of miles across, at most.

So, can we trust the seasonal forecasts from these models?

Based on last year, definitely not. However, since there will (should!) be an El Nino for the upcoming season, long-range forecasts can be a bit more accurate because El Nino forces the weather to behave in somewhat more predictable ways.

For now, treat all of this as entertainment and not a cause for celebration or as an excuse to grab a beer due to despair. It's still August, which means that you should go out hiking or biking and get strong for the snow that we hope will come in deep for the winter ahead.

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