February 2, 2012

The easiest storms to predict are those that move consistently from west to east across the country. These storms are like a freight train—they’re moving in one direction and not much is going to change their course.

The other side of the coin are storms that break off from the main flow. These storms are like a piece of paper floating in the wind—they could go in any direction at any time.

Luckily (do you sense the sarcasm?), the only game in town for the next few days is a storm that has broken off the main flow, otherwise known as a cut-off storm. As this storm heads across southern Colorado and into Kansas, snow will fall in Colorado and then move out into the plains of Nebraska and Kansas.

Graphic 5-day snow forecast

The five-day snow forecast through the weekend shows most of the action over Colorado.

As this storm dives down across the southern border of Colorado, it will actually pull up moisture all the way from the Gulf of Mexico. As this moisture hits the taller mountains of Colorado, it will fall as snow, with areas like [R1435R, Silverton] and [R511R, Wolf Creek] seeing 6 to 12 inches. Even bigger totals will fall in the mountains just west of Denver, with up to two feet possible at [R1673R, Echo Mountain].

While I have good confidence in the forecast for this storm, because it’s cut-off low and acts more like a piece of paper floating in the wind, I’m never that confident in the forecast. And just a few days before the storm, forecasts were all over the place and I had very low confidence of where the snow would actually fall.

When people (especially skiers and riders) complain that it’s very hard to predict the weather, this statement isn’t exactly correct. Some storms—the "freight train" ones—are easier to predict. But occasionally we get the “paper floating in the wind” storm, and these still give forecasters fits.

Meteorologist Joel Gratz is the creator of opensnow.com and is based in Boulder, Colo.