Jordan’s FR Forecast

Well, we had one great last hurrah with the May 11 to 13th snowfall, and we’ll doubtlessly have more snowfalls at the higher elevations from now to mid-June, but with the Eldora Snotel essentially showing the snowpack is hitting 0” at that comparatively low elevation, I think it’s time to wrap up my forecasts for the season.  As always, this season recap will consist of two parts.  First, I’ll do an overview of the season as a whole, and second, I’ll look at the results of my “analysis” of all of the retrospective discussions to try to learn about each model’s strengths and weaknesses to improve next year’s forecasts.  Season Recap: This was an average year in the front range, but with near record breaking snowfalls in other parts of our state, and gigantic record breaking snow years in Utah and California, average just doesn’t feel anywhere close to average in comparison.  I just feel fortunate that I was able to experience a bit of the record breaking year with a day at Sunlight, five days in Utah, and two days in California.  But I digress, back to our patrol zone. November started strong.  We faced some rough times, however, in December until it got close to Christmas.  Then we had a great Christmas and New Years.  We remained slightly above average in January and early February.  Late February and March were disappointing.  I was especially disappointed that the large spring storms we often get didn’t hit us in March.  Fortunately, although we had no cut-off lows in April, April still produced a lot of snow.  And then, we even got a big late dump in mid-May.  So, an average year overall.  And oh, it was really windy a lot – average again.  Below is the Lake Eldora Snotel Chart showing this year (black) and average (green): Which Model Was the Winner: Well, with the end of the year, it’s time to figure out which models did the best in predicting snowfall in our patrol zone.  Let me start with the usual caveat that my analysis is rather subjective – or as I might put it, this analysis is science like nutrition is science.  So take this with a large grain of salt.  I did more than fifteen retrospective discussions on five models (i.e., American, Canadian, European, UK Met and WRF), with over thirty data points on the American, Canadian, and European Models, so I’ll only include those five models in this analysis.  I’m not including the models that I have fewer than ten retrospective discussions (i.e., NAM and RDPS).  Accuracy – Of the five models from which I feel as if I have sufficient data, the one that most often was dead on or close to dead on was the Canadian Model (48% of the time), followed by the UK Met Model (38% of the time), then the American Model (34% of the time), then the WRF Model (22% of the time), and finally the European Model (21% of the time). Mode – When the models were off, I categorized them by way too low, too low, too high, and way too high.  While the Canadian, UK Met, and American Models were more likely to be correct than fall in any other category, the European Model more often was too low than it was correct, and the WRF Model more often was way too high than it was correct.  Median – Looking at the median prediction, overall, the American, European, and UK Met Model tended to underpredict storms by a bit, the WRF tended to overpredict storms by a bit, and the Canadian Model was evenly balanced. Outlier predictions – While the Canadian Model is the obvious winner thus far, the picture changes a bit, however, when you look at how often the models were way off in their predictions (both way too high and way too low).  The European Model was only way off 21% of the time (and never once this season way overpredicted a storm), the UK Met Model was only way off 25% of the time (and likewise never way overpredicted a storm), the American Model was way off 32% of the time, the Canadian Model was way off 33% of the time, and the WRF Model was way off 39% of the time. Conclusion – Looking at the whole picture, I’d say this year the overall best model was the Canadian Model (with the caveat that while it was the most balanced and the most correct, it was still wildly off fairly often).  The second best model was the UK Met (with the caveat that it tended to underpredict snow).  I’d put the American Model in third place, the European Model in fourth, and the WRF Model in fifth place. For all you meteorology nerds, I know this is heresy.  But after years of keeping track, while the European Model may be the best model overall worldwide, it is definitely not the best model for predicting snow in our patrol zone.  From my analyses, in 2020, the WRF Model came in first and the Canadian Model came in second.  In 2021, the WRF Model came in first and the Canadian and American Models tied for second.  In 2022, the Canadian Model came in first and the European Model came in second.  Now, in 2023, the Canadian Model came in first and the UK Met Model came in second.  It’ll be interesting to see the results next year, but for now, I’ll have some Canadian Bacon tomorrow morning while humming Oh Canada to celebrate our northerly neighbors’ ability to predict our snow. Cheers everyone.  And barring another June-uary like last year, I’ll restart these forecasts sometime in the late fall.  KBO. -Jordan (Monday 5/15/23 evening)

After a week and a half of dull weather, it looks like we have some interesting weather on our horizon.  On Thursday, a large closed low forms over Colorado.  These storms are rather unpredictable (as is evident with the wide distribution of model solutions listed below), and here are the various model forecasts: 16” – Canadian and European Models; 7” – RDPS and UK Met Models; 6” – American Model (but the grid I’m looking at averaging 9,439’ elevation is predicting 1” of rain before snow); 2” – NAM Model A smaller round of snow may hit our patrol zone on Sunday, with the Canadian Model calling for 2”, the European Model calling for 1”, and the American Model calling for nothing.  Regardless, at least there’s real snow in our forecast again! Retrospective Discussion: There have been any number of dustings over the last week and a half, but sadly the Cinco de Mayo storm never happened, so the American Model was more-or-less spot-on, with the European Model being too optimistic, and the Canadian Model being way too optimistic. Cheers. -Jordan (Monday 5/8/23 afternoon)

With the storm leaving, we’re going to be under a ridge of high pressure until roughly Cinco de Mayo.  Some thunderstorms and thundersnow are possible Monday May 1 to May 4.  Bear in mind that (i) models do an awful job predicting the amount of thundersnow, and (ii) some of this could come down as rain as well as snow. Things get interesting for the possible Cinco de Mayo storm.  A large closed low over California may come over our patrol zone producing somewhat significant snow (per the Canadian Model) or just kind of peter out as it goes from California to us producing snow showers (per the American Model), or somewhere in between (per the European Model).  Here are the model forecasts for our patrol zone: 10” – Canadian Model 3” – European Model ½” – American Model Here’s to hoping we get a good Cinco de Mayo snowstorm. Retrospective Discussion: Looking at the Lake Eldora Snotel SWE data (I don’t trust Snotel actual snow depth data at all), and comparing that to the Loveland Snotel SWE data and Loveland’s snow stake webcam from this same system, my best guess is that Eldora got 4” of snow out of this storm.  So the UK Met Model was dead on, with the RDPS and NAM Models pretty close.  The Canadian Model was too low.  The European Model and WRF Models were too high, and the American Model was way too high. Cheers. -Jordan (Friday (4/28/23) morning)

A system from the north northwest brings snow to our patrol zone on Friday.  There may be a small upslope component to this storm.  The models are still all over the map in the predicted amounts.  Here are the various model forecasts: 8” – American Model 7” – WRF Model 6” – European Model 4” – UK Met Model 3” – RDPS and NAM Models 2” – Canadian Model After that, a large ridge of high pressure (i.e., pleasant weather) builds for a while.  The American Model isn’t forecasting any snow for a long time, while the Canadian Model is predicting the next shots of snow on May 3 and May 5.  The European Model looks more like the Canadian Model on snow mid to late next week. Retrospective Discussion: The Lake Eldora Snotel reported .5” of SWE from this last storm, which looking at other Snotel reports with ski areas with working snow stake cams, should translate to getting 5-7” of snow.  (Can you tell I miss having the Eldora Snowstake Webcam running?)  5-7” is disappointing compared to the forecasts.  What happened?  Well, the low pressure system tracked further south than the majority of models (other than the European and UK Met models had predicted), which accounts for some of the disappointing results.  But still we usually do well even with that more southerly track.  So what happened?  Let’s look to someone who really understands Colorado snow – the great Joel Gratz.  He thinks the Front Range thunderstorm disrupted the flow of upslope moisture.  That makes perfect sense, and something my feeble mind would never have thought of.  In any event, the European Model was a bit low and the UK Met Model was a bit high, but at least they were both in the ballpark.  The other models did awful.  The RDPS and Canadian Models predicted twice as much snow as fell.  And the American, NAM, and WRF Models predicted three times as much snow as fell.  What a bummer. Cheers. -Jordan (Wednesday (4/26/23) afternoon)

Snow!  The first closed low in a while will be just south of our patrol zone on Tuesday, generating winds from the eastern half of the compass and hopefully a good shot of snow.  The exact location, speed, and shape of the low pressure will make a big difference in how much snow we ultimately get – which is obvious from the more than five-fold difference between the most pessimistic model solution to the most optimistic model solution.  Here are the various model forecasts: 22” – WRF Model 21” – NAM Model 19” – American Model 14” – Canadian Model 13” – RDPS Model 8” – UK Met Model 4” – European Model Snowshowers linger a bit.  Then, a smaller from the northwest comes in on Friday.  Here are the model forecasts for the Friday system: 4” – European Model 3” – American Model 2” – Canadian Model Spring looks to return on Saturday April 29 and stick with us from that point out to forecast fairyland. Retrospective Discussion: With Eldora now closed for the season, its snowstake webcam is down.  So, trying to piece together the snowfall one has to rely upon Snotel data or other sources, which aren’t nearly as reliable.  So, suffice it to say that we got somewhere between 2” and 6” of snow in the last system.  Cheers. -Jordan (Monday (4/24/23 morning)