Tuesday, April 9, 2013

Close but no Blizzard

As one who practiced inexact science for more than 36 years, I am always hesitant to criticize meteorologists when their forecast is less than completely accurate.  After all, there are many factors involved in making such forecasts and modern computer models, while steadily improving, are not infallible.  So, when, after days of warnings that Denver would be buried under a foot or more of snow and be faced with a raging blizzard, Winter Storm Walda passed through our region without the expected armageddon, I was not overly surprised.

The first clue that our official forecast might not be accurate occurred yesterday afternoon as severe thunderstorms, some tornadic, ignited in northeastern Colorado.  Pacific storms that generate heavy upslope snows in Metro Denver generally move eastward along the Colorado-New Mexico line and the brunt of their severe weather develops across the Southern Plains.  The central low of Walda and its associated energy was moving further to the north, taking a route from the Four Corners toward western Kansas.  While we received about five-six inches of snow and the predicted polar air in Metro Denver, the winds from Walda have been from the north, negating much of the upslope effect; the latter is most potent for Denver when the winds arrive from the northeast.  In the end, most of the snow has fallen across Wyoming and South Dakota and blizzard conditions have been limited to the High Plains (where they are common during almost any snowstorm).

Except for the extreme cold air, Walda was fairly typical for April Front Range snowstorms and the media excitement over the past few days has proved to be a bit over the top.  On the other hand, in light of our ongoing drought, we could have used a record spring snowfall.