Author Archives: WeatherGuys Editor

What is graupel?

Graupel is a type of frozen precipitation. Southern Wisconsin experienced this on Thursday afternoon.

Most clouds outside the tropical regions have temperatures that are below freezing somewhere in the cloud. These cold clouds are likely to have frozen cloud particles. They are also likely to include supercooled water drops, drops made of water that are below the freezing point. Continue reading

Category: Meteorology, Seasons

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Will we hit 80 degrees again this year?

We will not see 80 degrees again this year.

The last time Madison was officially 80 degrees or warmer was Sept. 21, the last official day of summer. In fact, 13 of the first 21 days of last month we were at least that warm — fairly remarkable. Continue reading

Category: Climate, Meteorology, Seasons

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How are clouds named and why are the bottoms flat?

In 1803, British pharmacist and chemist Luke Howard devised a classification system for clouds. It has proved so successful that meteorologists have used Howard’s system ever since, with minor modifications.

According to his system, clouds are given Latin names corresponding to their appearance — layered or convective — and their altitude. Clouds are also categorized based on whether or not they are precipitating. Continue reading

Category: Meteorology

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Another example of unprecedented weather extremes

Another entry in the category of unprecedented weather extremes comes from the tropical Atlantic basin where, last week, Hurricane Fiona wrought devastation to the Commonwealth of Puerto Rico, still reeling from its assault by Hurricane Maria eerily precisely five years earlier.

Fiona dropped upwards of 30 inches of rain on the south shores of Puerto Rico before heading north into the Atlantic, where it systematically strengthened into a Category 4 hurricane with sustained winds of more than 130 mph. Continue reading

Category: Meteorology, Phenomena, Severe Weather, Tropical

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What can happen to hurricanes when they move into the mid-latitudes?

Hurricanes are large-scale, organized storms that form in the tropical latitudes.

They are fueled by the enormous amount of heat released when water vapor, evaporated off the warm tropical ocean surface, changes phase to liquid and ice in the thunderstorm clouds of the hurricane.

They are smaller in areal extent than the storms that commonly affect us in the mid-latitudes here in Madison. Continue reading

Category: History, Meteorology, Severe Weather

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