Here we go again (and again)

Another snowstorm D.O.A?
You will remember a few weeks back when I posted about what was at one point a very promising looking storm 7 days out, but what would become only a dusting last Saturday. We are at similar crossroads again tonight, with our much advertised chance for a "significant" snowfall now looking but a minor event this coming week.

Take a look at the GFS model from last Friday for snowfall totals through Feb 23 (left), compared to tonight's 0z GFS model run for the same period.

There are several things to take away from this image. One, is the rather indisputable consistency with bringing a rather potent winter storm to the plains states this week. The other is the trend of the heaviest snow pushing east of eastern Colorado, and a rather stubborn dry slot along the Front Range and Denver. It is fair to call this storm's setup "near perfect", but that can (and likely will) be the difference of 8 - 12" from the "perfect" setup.

Euro 12z - Sunday Feb 17What is worse, is that the EURO model is in agreement, and has been the more reliable model this winter. The 12z model run of the Euro this afternoon coughed up 0.10" of liquid (down from >0.5" the night before) which would produce approximately 1 inch of snow for Denver.

If I wanted to be completely reasonable, even being several days out, I would inform you that this absolutely is not the storm for us. If I had to forecast totals right now I would see (optimistically) another 0 - 3" event is in store for the greater Denver area Wednesday into the Thursday, much like virtually every snowfall this season. However, it's difficult for me to be completely reasonable in such scenarios, so I will leave the door open to the possibility of this storm still producing something for us in the end. There are enough favorable conditions around to make this happen (moisture, cold air, dynamic forcing (lift!)), that I will hold off on removing the "?" from the sub-header of this post until I have worn-out every possible scenario. Stay tuned!

Longterm models not all bad
Looking ahead to the next few weeks, the GFS extended model continues to keep an active storm track across much of the United States. The midwest, which has been largely spared from winter in recent history, should be prepped for a very snowy second half of February. While the pattern will continue to bring disturbances through northeast Colorado through the 16 day period, it's likely that most (if not all) will leave us wanting more. The Northern Atlantic Oscillation (NAO) is forecast to remain negative through the end of February, which traditionally means active weather for the plains and east, leaving Denver on the cusp.

I am optimistic (why?!) for this pattern to continue to bring us chances for snow well into March, with the possibility of a good western trough reemerging just in time for our snowiest month. There is reason for hope - but we have a lot of work to do to break this stubborn drought, so no promises. More to come on the extended outlook in the near future I hope.

Brendan Heberton

Brendan is founder of Weather5280. He is co-founder of FreshyMap, and develops software for geospatial data analysis and visualization.

Denver, Colorado
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