How’d We Do? Reviewing the First Winter Storm Forecast of 2020-2021!

As someone who forecasts the weather it's important to me to review my forecasts to see what went well, what went not so well and how I can improve not only the forecast by my communication of the forecast. I'd be lying if I told you that I review every single one of my forecasts (I probably would if I had more time) but I still find it pertinent to look at a good number of my forecasts to check in on how I do from time to time.


Snowfall Forecasts

Overall I'm quite happy with where the snowfall accumulation forecasts ended up. I am re-posting my maps along with NWS verified totals for each of the areas that had data (red --'s mean there was no official data reported) for comparison to see how things turned out.

The Palmer Divide snowfall forecast turned out relatively well. Some areas were spot on and those that were outside my forecast range were not outside by much. Generally areas that did fall outside busted low, which I said many times that may be the case due to warm ground temperatures
The snowfall forecast for Southern Colorado was a bit more challenging as some areas were in range and some were outside both high and low. Elevation made a big difference but the surprises were a few of the plains location busting high.
Northern Colorado was by far the trickiest but most locations that fell outside of my forecast range were on the low side... which should be no surprise based on the rest of my forecast!

A couple of thoughts about the maps and totals above... I think the snow forecast went well as most areas were within range or below forecast which is what I figured would happen. The second thing I notice is how hard snow reports are to come by especially in rural areas. I know there aren't a lot of people out in these areas but it would be nice if we had a few more weather watchers around willing to set up stations and take snow measurements. It is early in the season though so it's possible more of these will fill in as we go through the year.

Communication/ Impacts/ Models

GFS model was forecasting nearly 20 inches of snow for most of the runs for this storm...

Remember the model shots like above? A good amount of our weather models had this storm pegged as a major snow producer in the 1-2 foot range for the front range of Colorado. While this generated a lot of buzz on TV and social media, the simple truth is that this was very unlikely to happen. This early in the year a high sun angle enhances melting of snow on the ground and the temperatures only a few days before the arrival of this storm were in the 100's!

We know for a fact that models do not handle those two variables very well so despite those inflated numbers I tried to communicate in every post that 20 inches of snow on the ground for Denver was very unlikely. Overall I'm happy with this communication for these posts, I went back and looked at each forecast outlook to make sure my thoughts were communicated well in each post.

As far as impacts, the storm behaved pretty much as expected; most roads stayed wet, snow accumulation was minor and the storm itself was generally a non-factor for most folks. Exception to that being the higher elevations in the foothills and mountains, but even then they handled things pretty well.

The main communication points around this forecast was the uncertainty due to it being so early and so powerful a cold front - also how models were not handling this storm well and snowfall numbers were way overblown.

 

Overall Grade and Summary

A-

Those who have followed me for awhile know that when I blow a forecast or something doesn't work out I can be quite critical of myself - which is always ok. When a forecast works out I am super happy, but this one was special because it was one of the more challenging ones I've had in awhile. There were certain points where it was easy to say, "we have absolutely no clue how this storm will pan out." I was able to stick to my instincts and meteorology knowledge and hammer out a forecast that verified pretty well for a lot of areas.

It's difficult to get snow amounts and locations 100% right, but I feel like if people are prepared and impacts turn out as expected and snowfall amounts are at least in the ballpark (especially with a storm as difficult as this) then you're on the right track.

 

About John R. Braddock 512 Articles
John R. Braddock is a NOAA/NWS Certified Storm Chaser and Amateur Meteorologist living in Castle Rock, Colorado. A graduate of Colorado State University with a Bachelor's in Computer Science and a Colorado native, he specializes in short range forecasting, severe weather and mountain weather dynamics.

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