Category Archives: Meteorology

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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Did weather play a role in D-Day?

Friday marked the 70th anniversary of the Allied invasion of Europe and the beginning of the end of Nazi tyranny and murder in World War II. A perfect combination of full moon (for nighttime aerial navigation purposes), low tide (so that German mines in Brittany would be exposed) and light winds were necessary to give the invasion any reasonable chance of success.

Thus, days on which the tides and phase of the moon were optimal were known some weeks in advance. As late May arrived, it became increasingly clear that choosing among those optimal days for invasion would depend crucially upon the weather and the ability to make an accurate forecast of weather conditions.
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Category: Meteorology, Severe Weather, Weather Dangers

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