- May 30, 2022 4:50 pm
The second half of May has been great – Mayuary as some people have called it – and it looks like June will start off with a (snow filled) bang! A small upslope coupled with a jet streak should produce a real snow storm on Tuesday evening through Wednesday (June 1) morning. Here are the various model forecasts: 14” – RDPS Model 13” – NAM Model 11” – American Model 10” – European Model 8” – Canadian Model 5” – UK Met Model 2” – WRF Model Any snow this time of year is good to delay the run-off and increase the quality of late spring and early summer skiing. And fingers’ crossed the more optimistic model solutions come to pass, and we get close to a foot (or more) of snow. Come on Juneuary! Retrospective Discussion: The May storm delivered – the primary storm dumped 14” in Nederland and 1.1” of SWE at the Lake Eldora Snotel. And then more snow fell over the next several days. A few thoughts on my prior forecast. Interestingly, the snow was lighter than I expected. It also appears to have been predominantly fueled by a jet streak – which I relegated to my third reason for the snow in my forecast (and part of the reason the snow was lighter). Regardless of my so-so forecast, it was a great storm! For what it’s worth, the American and Canadian Models overpredicted the storm, and the European and UK Met Models underpredicted the storm. Cheers. -Jordan (Monday (5/30) morning) Note: Unless otherwise noted, all forecasts are for 10,000’ in exposed areas. References to American Model are the American (GFS) Model. References to the Canadian Model are the Canadian (GDPS) Model. References to the WRF Model are the CAIC WRF Hi-Res Model. References to the European Model are the European (ECMWF) Model.
- May 17, 2022 11:31 pm
Okay, this system is way too exciting not to write about, even though I already posted my season wrap-up. A complex system approaches on Friday from the north northwest – with snow being fueled by primarily by (i) a low pressure system with the low currently forecasted to center roughly in the middle of the state (a good spot for it to be for our patrol zone), and (ii) a cold front. Although probably less important, there may be a jet assist to snowfall as well. Temperatures will drop from a high of almost 70 degrees at 10,000’ on Thursday to a low Saturday night of perhaps 15 degrees. That’s a heck of a temperature shift. Although this is a cold system for this time of year, make no mistake, this Spring storm will likely produce heavy snow as the temperatures are still rather warm compared to our winter storms. There’s still major model disagreement over the power of this storm (and frankly the three major models have been bouncing around quite a lot for the last few days). So, as of the time of writing this, what are the models predicting? The American and Canadian Models are both bullish, but the European and UK Met Models are not. Let’s break down this storm into two rounds. Round one, the bigger snowfall round, will be Friday at noon to the end of the day Saturday. Here are the model snow forecasts for our patrol zone: 25” – American Model 22” – Canadian Model 6” – European Model 3” – UK Met Model We may be looking at a decent powder day on Winter Park’s scheduled closing day. For those curious, the RDPS and NAM Models are only predicting out to midnight on Friday at this point, but the RDPS Model is calling for 12” by midnight, and the NAM is calling for 4” by midnight. And this system is not yet in range of the WRF Model. The second round is Sunday afternoon to Monday night. Here are the model snow forecasts for our patrol zone: 4” – Canadian Model 3” – American Model Dusting – European Model 0” – UK Met Model Well, I’m very excited to keep watching this system. Fingers’ crossed it pans out. And fingers’ crossed that this is not actually the last hurrah, and I have to write at least one more post before the season is over. Cheers. -Jordan (Tuesday (5/17) evening) Note: Unless otherwise noted, all forecasts are for 10,000’ in exposed areas. References to American Model are the American (GFS) Model. References to the Canadian Model are the Canadian (GDPS) Model. References to the WRF Model are the CAIC WRF Hi-Res Model. References to the European Model are the European (ECMWF) Model.
- May 9, 2022 11:08 pm
“It could have been worse” is hardly a rallying cry, but that’s how I’d sum up this season snow-wise in our patrol zone. Early November started off strong, but then a horrific lull put us well below average until I flew up to Alaska in late December. As soon as I got on a plane to Alaska, it stopped snowing in Alaska and started snowing in our patrol zone. By early January, things were looking decent, but probably since I was back in town, things never got too exciting again until April. From early January to the end of March, the snowfalls while slow and steady, never seemed to stay up with our average snowfall and the season was consistently just a little below average. Somehow the weather gods missed the other times I was out of town — as none of those times were as stormy as when I was in Alaska. At least we got some good late season snowfalls in April. However, we never got the huge upslope snow event we get so many times in March or April. Overall, compared to the average, our two best months this season were January and April, and our worst month was February. Below is the Lake Eldora Snotel chart for the season, with the green line representing average, black line representing 2022, the purple line representing the best season, and the red line representing the worst season. Well, it could have been worse. Let’s turn to my forecasts, and how the models did this season. How Did the Models Do? As I have in prior years, I’m always curious to see how each of the weather models performed for our patrol zone over this past season. Hopefully this can improve my forecasting for future seasons. In the past I’ve learned that the NAM, RDPS, and HRRR add little to my forecast, and traditionally the WRF has led the pack of the models with either the Canadian or American models nipping at its heels. But, as this season went on, I started getting the feeling that the WRF wasn’t doing so well, while (a certain model mentioned below) seemed to be the most reliable. Let me start with my usual caveats that my comparison of how the models did is based upon some back of the envelope math (and math is hardly my strong suit). And that math is based upon my subjective retrospective discussions. So, take this with a large grain of salt. Well the results are in. I got between 20-40 data points on five of the models – American, Canadian, European, UK Met, and WRF, so I’m only including those in this analysis. Unlike the last two years when the WRF Model was the most accurate snow forecasting model for our patrol zone, for some reason (perhaps known to those much smarter than me), the WRF Model fell on its face this past year. Well then, which model was the winner? It was an easy call. Drum roll please …. The Canadian Model. On the good side, the ratio of being dead-on accurate compared to my total references to the model in the forecasts was 23% for the Canadian Model, a bit higher than the WRF, and much higher than the other models. On the bad side, the WRF won the unenviably prizes of having the highest ratios of way underpredicting snow, somewhat underpredicting snow, and somewhat overpredicting snow, while the UK Met won the unenviable prize for the highest ratio of way overpredicting snow. Of course, these are just ratios, and so the last sentence left out the most ignominious storm over and under predictions of the year – and that sorry prize goes to the American Model. My favorite missed prediction was the American Model’s 62” prediction when 4” actually fell. Looking at the overall numbers, the Canadian Model was by far the best model for predicting snow this season. I think the European Model came in second. Hard to say who was third or fourth (between American and UK Met Models), but sadly I think the WRF model came in last. It was just constantly off. So, pull out a Molson or a Labatt beer, eh. Cook up some Canadian Bacon, eh. And, toast to the Canadians who did the best job building a model to predict snowfall in our patrol zone, eh. Kind of figures, doesn’t it, that a land of snow and ice would build the best weather model for this past season, eh? Thanks everyone for reading these forecasts this season, eh. And, look forward to seeing you all at the patrol picnic and/or the Mt. Russel ski day, eh. Cheers. -Jordan (Monday (5/9/22)) Note: Unless otherwise noted, all forecasts are for 10,000’ in exposed areas. References to American Model are the American (GFS) Model. References to the Canadian Model are the Canadian (GDPS) Model. References to the WRF Model are the CAIC WRF Hi-Res Model. References to the European Model are the European (ECMWF) Model.
- May 5, 2022 10:37 pm
The weather looks warm and pleasant for a while without any good spring storms on the horizon. Boo! About time to throw in the towel on this winter of weather forecasts for our patrol zone. I’ll keep an eye on things, and if there’s nothing interesting snow wise in a bit, I’ll stop posting forecasts and just write a year wrap-up post. Friendly reminder that as the temperatures warm over the next week, we’re likely going to see our annual spring wet slab cycle take place soon. Be careful about skiing the big lines out there until the snowpack consolidates in a couple of weeks. If you really care about the boring weather in the forecast, it looks like zonal flow for the next few days. Then, a storm system well to our north may produce a little snow (or rain) on Saturday night-ish in the 0-3” range. There may be a second wave from that system on Monday, but the major models aren’t call for any precipitation in our patrol zone for that round. Then the next snow forecasted isn’t until out in forecast fairyland around May 15. Look forward to seeing everyone at the patrol picnic and/or the patrol Mt. Russel ski day. Retrospective Discussion: On the most recent storm, happily, the European and Canadian Models’ solutions on Monday for the closed low to go through Colorado panned out (as opposed to the American and WRF Models’ solutions for the closed low to go through Wyoming). That means we got a nice shot of spring snow on Tuesday to Thursday! Hard to estimate, but probably our patrol zone got 7-10” of pretty heavy powder. So the Canadian Model was spot on, the European Model was a touch high, the UK Met model was a touch low, the American Model was embarrassingly low, and the WRF model’s ½” forecast was the worst of all. Considering the system predicted by the American model but not predicted by the Canadian Model for early next week doesn’t look like it’s happening, the Canadian Model overall did an impressive job on the two systems, while the American Model fell flat on its face. If there’s anything redeeming for the American Model, it did a better job on this week’s storm than the Canadian or European Model 5-7 days out, though they did a better job as the storm got closer. Cheers. -Jordan (Thursday (5/5) evening) Note: Unless otherwise noted, all forecasts are for 10,000’ in exposed areas. References to American Model are the American (GFS) Model. References to the Canadian Model are the Canadian (GDPS) Model. References to the WRF Model are the CAIC WRF Hi-Res Model. References to the European Model are the European (ECMWF) Model.
- May 3, 2022 12:13 am
Lots to talk about, but in sum, the models are all conflicting and it’s hard to say what’s in store for us snowfall-wise for the next ten days. As the current storm exits the region, hot on its heels is another closed low. The American model has it tracking too far north for us to get a real wallop of snow, though the European and Canadian Models are more optimistic of it being far enough south for some real snowfall. Snow looks to start Tuesday evening and go through Wednesday evening. The models are all over the map on how much snow we’ll get. Hard to make any predictions. Here are the various model forecasts: 13” – European Model 9” – Canadian Model 6” – UK Met Model 2” – American Model ½” – WRF Model Then, we’ll have a ridge of high pressure on Friday and Saturday, before a potentially large system starting on Sunday (5/8). The American Model is bullish. Decent sized trough, and the definite possibility that it will not just be a closed low but a cut-off low, which if true and if it’s in the right spot, could be fantastic. (A cut-off low is a low pressure that gets cut-off from the main west to east track and meanders around and snows for a while). However, the Canadian Model is not bullish at all, and predicting little more than a dusting. Here are the Sunday to Wednesday forecasts: 19” – American Model 8” – European Model 2” – Canadian Model If the Canadian Model is right on the first storm and the American Model is right on the second storm, we’re in for a doozy! And if the American Model is right on the first storm and the Canadian Model is right on the second storm, we’re going to get skunked. To put the unpredictability into context, although the University of Utah doesn’t downscale their ensemble model for our patrol zone, they do for my beloved Berthoud Pass, which isn’t too far away. Four of the ensemble runs are predicting over 40” in the next week, while three of the ensemble runs are predicting less than 10”. We’re not talking about one or two outliers, but the ensembles are all over the map. (I never tire of that pun.) Fingers’ and toes’ crossed. -Jordan (Monday 5/2 afternoon) Note: Unless otherwise noted, all forecasts are for 10,000’ in exposed areas. References to American Model are the American (GFS) Model. References to the Canadian Model are the Canadian (GDPS) Model. References to the WRF Model are the CAIC WRF Hi-Res Model. References to the European Model are the European (ECMWF) Model.