36-44″ of Snowfall in Model Forecasts, but What Can We Really Expect? Rain.

EDIT: This article has gone viral and I want to make perfectly clear that I am not predicting snow as the images posted in other areas make it seem. At this point in time, this looks to be a rain event and I was illustrating how ridiculous the models were acting. You can see the full write-up below without the over-hyped image. Thanks for reading!

There is certainly no shortage of buzz about next weekend’s possible storm system that is poised to hit Colorado. Meteorology forums and forecasters are beside themselves with the possibility of heavy snowfall that this storm contains. One of the reasons that the hype train is already in full effect is that the long range models (GFS, GEFS, ECMWF, and CFS) all have reasonable agreement on the position of the system and the timing, something that hardly ever happens more than a couple days in advance. We have all the great ingredients snow-hype-trainneeded for an epic snow storm with deep upslope wind flow, plenty of moisture in the atmosphere, and a blocking pattern that would keep the precipitation in the region for a few days. With that being said, caution needs to be exercised when talking about this storm because, while there is agreement from the models, there are still far too many variables at play and there is too much time for the models to change before we get to the actual storm.

Storm Overview

A low pressure system will begin to develop over the Rocky Mountain region Thursday and Friday and will move to the east of the Rockies on Saturday and intensify. The storm begins to really sling moisture at us around noon on Saturday and continues through Sunday and into Monday morning. Models have gone crazy with the snowfall on this system predicting up to 45″ of the white fluffy stuff in Denver and the surrounding areas, but this seems absolutely absurd given the temperatures at the time. While winds will be gusty during the event, there is no expectation of a blizzard or heavy snowfall at this point in time.

Primary Concerns With Expecting This To Be A Huge Snow Storm

Proclaiming that this will be an enormous snow storm is foolhardy at this point in time. As we all know, predicting big events like this is very tricky. When warm temperatures and the fact that the storm isn’t expected for another five days come into play, it goes from being tricky to predict to almost impossible. While the models have performed well with several big storms in the continental US over the past winter, they have had their fair share of failures as well.

Pumping the brakes on the hype train is needed due to a few concerns at this time:

  1. While the temperatures are supposed to drop with this system, they are still very warm and, while we still might see precipitation, it would likely fall as rain. The amount of cold air being brought down from Canada doesn’t increase to favorable amounts until a lot of the moisture has already fallen.
  2. Even if the air temperature drops low enough to warrant snowfall, the ground temperatures are still very warm due to the higher temperatures that we experienced last week and will again experience leading up to this event. So, even if snowfall does occur, there is a significant chance that much of it will melt once it hits the ground.
  3. The exact shape and position of the low pressure center is still being resolved and varies from model to model. If it elongates or shifts to the north, we are going to see small amounts of moisture and Wyoming would see more. Even if it ends up as the stereotypical circular cut-off low, it needs to be in the perfect position to give us big snow.
  4. We are still five days out from this event and that is a lot of time for parameters in the models to shift and alter important details of this storm.
    Screen Shot 2016-04-10 at 6.15.20 PM

    Pressure (teal lines) illustrating elongated low with 3-Hour Accumulated Liquid Precipitation at Midnight on Friday night

The Final Word

While the potential of a large accumulation snow storm is certainly exciting, there are still too many unknowns to begin making proclamations about what will actually happen. This will definitely be a storm that we watch over the next few days to determine the likelihood of actually being impacted by it. Making snow or rain accumulation predictions would be foolish at this point and would be anything but accurate, but as the week continues I’ll start putting out rough accumulation predictions as we try to nail down what this storm is actually going to bring us. With that being said, there is nothing to suggest that this will be a big snow event, it will likely be rain and that’s perfectly fine because we need the moisture regardless!

I’ll keep an eye on it and will post updates with new information as it becomes available! If you have any questions or comments, feel free to let me know below!

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