The Weather Guys

Rick Fink of Mayville blows snow April 19 in front of his tractor and pulls his planter behind, for fun!
(Photo credit: Ryan Andres, Agri-View)

As a very unusual month of April comes to a close, it may be of interest to note some of its ramifications across the country, both good and bad.

Among the headaches that have resulted from the unrelenting wintry nature of the month was the cancellation of 28 Major League Baseball games through the late part of the month — an all-time record.

To put this number in perspective, 2016 suffered only 25 cancellations through the entire season!

And, of course, a large number of these cancellations were a result of cold and snow.

Other ramifications of the weather this month include a late start for farmers, some of whom are as much as two weeks behind as a consequence of low soil temperatures brought on by the persistent cold.

On the other hand, it may be somewhat comforting to know that the unseasonable coolness of this month has also had a few positive aspects to it.

To this point in the month, not a single tornado has been reported in Oklahoma — the longest the state has ever gone into a year without a tornado.

The dearth of tornadoes is widespread across the Plains as only 229 have been reported across the country so far, about 33 percent fewer than in an average year.

The continued cold through most of the month has been the result of frequent invasions of Arctic air from the north. Such air is relatively dry which has prevented the moist air necessary for the development of severe thunderstorms from pooling over the Plains.

So, as we finally rid ourselves of a notably cold April, it is only fair to remember that it was not all bad.

Matt Erdmann, of Madison, takes advantage of the wind as he kiteboards at Olbrich Park on the shore of Lake Monona. The wind is simply air in motion, flowing from high atmospheric pressures to low pressures. (Photo credit: Amber Arnold, State Journal archives)

A pressure gradient is how fast atmospheric pressure changes over distance. So, when pressure changes rapidly over a small distance, the pressure gradient force is large. Strong winds almost always result from large pressure gradients. Recently, southern Wisconsin has been under the influence of a weather pattern that has strong pressure gradients and strong winds.

The Coriolis force pulls the wind to the right so that in the Northern Hemisphere winds blow counterclockwise around low pressure systems and clockwise around high pressure ones. With your back to the wind, lower pressure is to the left.

What the wind is blowing over can also influence the wind speed. Over the open lakes, the wind will be faster than through a stand of trees, where it will be slowed by friction. In the presence of buildings, the air can be funneled between buildings and pick up speed.

During this time of the year, thunderstorms also can cause strong winds. Rain falling from a thunderstorm evaporates underneath the cloud, cooling the air beneath it. This cold heavy air plunges to the surface and “splashes” against the ground like a bucket of cold water. The air then rushes sideways resulting in strong winds.

These “microbursts” are capable of producing winds of more than 100 mph, causing significant damage while lasting for only five to 15 minutes.