Category Archives: Climate

Are we seeing more ozone advisories in southcentral Wisconsin?

Ozone (O3) is a molecule formed by three oxygen atoms.

Ozone that resides in the stratosphere absorbs ultraviolet rays of the sun, protecting life on Earth’s surface from these high-energy electromagnetic waves. O3 also can occur near the ground, where it is considered a pollutant, as it is a chemically reactive gas that can cause respiratory problems when breathed. Continue reading

Category: Climate, Phenomena, Weather Dangers

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Was May abnormal this year?

The just completed month of May was quite unusual in southern Wisconsin this year.

First, it was a bit cooler than normal, with the average temperature ending up 0.6 degrees below normal. Dryness over central and western Canada brought large wildfires to those areas much earlier than normal this year, and the smoke from those fires gave us a number of orangey sunrises and sunsets this past month, which are more normal in July and August. Continue reading

Category: Climate, Meteorology, Seasons

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Are the number of thunderstorms in Wisconsin decreasing?

This question comes from one of our readers, based on casual observation. It is always good to get data and analyze such a generalization to find the best answer. So, we turned to the Wisconsin State Climatology Office.

The National Weather Service records the number of thunderstorm days at several sites across the U.S. A thunderstorm day is when thunder or lightning is detected at least once during the day. Since the mid-1990s, the nation’s primary surface weather observation network is the Automated Surface Observing Systems, or ASOS program, which has essentially replaced human observers. Continue reading

Category: Climate, Meteorology, Severe Weather

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Can record high and low temperatures help define regional definitions of seasons?

Though it now seems to be fully in swing, the spring has sure seemed delayed in coming this year in southern Wisconsin. This made us wonder if there might be a more refined, and local, way to think about the calendar-day boundaries of the seasons.

In research undertaken to write a recent column, we catalogued Madison’s record high and low temperature data for each calendar day employing data that went back to 1939. An interesting partition of the full year resulted from this simple analysis. Continue reading

Category: Climate, Meteorology, Seasons

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What is happening with ocean temperatures?

Scientists record global ocean temperatures using satellite observations. Since mid-March, the global average sea surface temperature has been more than 70 degrees, a record high temperature. This indicates rapid warming, which is associated with global warming and ocean circulations.

El Niño and La Niña are climate patterns in the Pacific Ocean. Normally, the trade winds blow west along the equator, moving warm water from South America toward Asia. To replace that warm water, cold water rises from the ocean depths — a process called upwelling. That means cold water rises to the surface near South America. Continue reading

Category: Climate, Phenomena, Tropical

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