Category Archives: Meteorology

What is an equinox?

The equinoxes (from “equi,” meaning “equal,” and “nox,” or “night”) occur when the sun’s rays strike the equator at noon at an angle of 90 degrees.

In the Northern Hemisphere, the vernal or spring equinox occurs around March 20, and the autumnal or fall equinox occurs on September 22 or 23. Continue reading

Category: Meteorology, Seasons

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What is a funnel cloud?

A funnel cloud gets its name from its shape — it is a funnel-shaped protuberance from the base of a thunderstorm.

It is composed of water droplets and is often associated with a supercell storm. The funnel cloud often has rotation, and when it does, it’s a harbinger of possible severe weather. Continue reading

Category: Meteorology, Phenomena, Severe Weather

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Does meteorological science have an impact on public policy?

One key piece of the world’s evolution toward nuclear sanity during the height of the Cold War was motivated by growing understanding of a fundamental meteorological phenomenon: the development of what’s now known as upper-level frontal systems.

The first atomic bomb was tested on July 16, 1945, in New Mexico, ushering in the nuclear age. Over the next decade and a half, continuously bigger bombs were tested in our atmosphere and oceans. Most of these bombs were exploded in the Earth’s stratosphere under the assumption that the air never mixed downward into the troposphere, where we all live. Continue reading

Category: Meteorology

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Is there any trace of winter left in the Northern Hemisphere?

We have made reference a few times in this column to the areal extent of cold air over the Northern Hemisphere as a measure of wintertime severity, that is, the geographic reach of air of a certain temperature.

Specifically, we have reported on the 23-degree air at 1 mile above the ground (where the atmospheric pressure is just 85 percent of its near-surface value). By mid-July it is impossible to find air that cold at that elevation in the Northern Hemisphere. Continue reading

Category: Meteorology, Seasons

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When is Wisconsin’s tornado season?

Tornadoes can happen in just about any location and at any time, although the chances of having one in late fall and winter are small.

For example, there have been only six tornadoes in Wisconsin during the month of November, and Wisconsin has never recorded a tornado in February.

On average, there have been 21 tornadoes touch down in Wisconsin in a year, with a record 62 tornadoes in 2005. For the 20-year period between 1991 and 2010, there was an average of nine tornadoes in the month of June. Continue reading

Category: Meteorology, Severe Weather

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