Category Archives: Phenomena

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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Does lightning add nitrogen to the soil?

Our bodies need nitrogen to make proteins. The atmosphere’s composition is 78% nitrogen, but the nitrogen in the air is not available to our bodies.

The two atoms in the airborne nitrogen molecule are held together very tightly. For our bodies to process that nitrogen, the two atoms must separate. Continue reading

Category: Meteorology, Phenomena, Severe Weather

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When does fog mostly occur in Madison?

Fog can occur anytime of the year, depending on the type of fog. In southern Wisconsin, fog is most frequent in the morning, between about 6 and 8 a.m. Fog is a cloud in contact with the ground, and it … Continue reading

Category: Meteorology, Phenomena

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What causes lightning?

Charges form in a storm composed of ice crystals and liquid water drops. Winds inside the storm cause particles to rub against one another, causing electrons to be stripped off, making the particles either negatively or positively charged.

The charges get grouped in the cloud, often negatively charged near the bottom of the cloud and positively charged up high. This is an electric field, and because air is a good insulator, the electric fields become incredibly strong. Continue reading

Category: Meteorology, Phenomena, Severe Weather

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What is an atmospheric river?

Atmospheric rivers are relatively narrow regions in the atmosphere — typically 250 to 375 miles wide and well over 1,000 miles long.

These sky rivers transport water vapor outside of the tropics to mid-latitude and polar regions. We estimate that 90% of Earth’s north to south water vapor transport is done through atmospheric rivers. Continue reading

Category: Meteorology, Phenomena, Weather Dangers

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