Category Archives: Meteorology

What is the heat index?

The heat index indicates how hot it feels. It is expressed as a function of air temperature and the relative humidity.

The heat index temperature is for standing in the shade; when exposed to direct sunlight, the heat index value can be increased by up to 15 degrees. Continue reading

Category: Meteorology, Seasons

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When was the year without a summer?

The summer of 1816 is known as the year without a summer in eastern North America.

While extensive weather observations were not available, people’s journals documented the cold weather. Snow fell on June 5 in Vermont with temperatures in the low 30s, following a day with high temperatures in the upper 80s. Continue reading

Category: Meteorology, Phenomena

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How do you measure how hot the summer is?

After experiencing our first 90-degree day of the season on Friday, many people are wondering what we might expect this summer.

It turns out that the number or 90-degree days each summer is extremely variable here in Madison. From 1971 to 2015, the average number of days at or above 90 in Madison was 10.96. This average, however, struggles to convey a sense of the variability. Continue reading

Category: Climate, Meteorology, Seasons

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What can be learned from the recurrence of extreme weather events?

In 2004, the Boston Red Sox won the World Series for the first time in 86 years and their loyal fans were ecstatic. In the very next year, the Chicago White Sox won their first World Series title in 88 years.

Never in the long history of baseball had two teams that had been denied championships for so long won those long-coveted titles in successive years. This circumstance was at least partially a function of the changes in baseball brought about by free agency — a fundamental change to the rules. Continue reading

Category: Climate, Meteorology, Severe Weather

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How will a warmer planet affect the severity of mid-latitude storms?

In previous columns we have discussed how the phase change of the water substance from invisible, gaseous water vapor into liquid water (through condensation) or into solid ice (through freezing) releases latent heat into the surrounding environment.

This heat can change many aspects of the nature of the mid-latitude storms in which the phase change is occurring. Continue reading

Category: Climate, Meteorology, Severe Weather

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