Category Archives: Meteorology

How unusual is our roller coaster winter?

It doesn’t take an exceptional attention span to realize that this year’s cold season (starting in November) has been very changeable.

November was 6.1 degrees colder than normal, then December was surprisingly mild (5.8 degrees above normal). As of Thursday — mid-month — January has been 8.5 degrees below normal. Continue reading

Category: Climate, Meteorology, Seasons

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Are the Great Lakes’ water levels normal?

For the first time in about 25 years, the water level of the all the Great Lakes is above normal. Lakes Superior, Michigan and Huron are about 5 inches above the long term average.

This ends a 15-year period where lake levels have been below historic averages. Continue reading

Category: Climate, Meteorology, Seasons

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What rare weather event did we experience last month?

Madison’s overnight low temperature of minus 3 on Dec. 28 was a relatively rare event, all things considered.

As we all know, the temperature dipping below zero in winter is not unusual. But it doesn’t usually happen without snow on the ground, and there are good reasons for that. Continue reading

Category: Meteorology, Seasons

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What are geomagnetic storms?

Our sun is an active star that has storms. Sometimes the sun ejects a cloud of gas, called a coronal mass ejection or CME. CMEs are often associated with solar flares, and it takes about two to three days for the charged particles in this gas to reach Earth. Earth’s magnetic field deflects these particles toward the North and South Poles.

Unfortunately, solar electrons and protons from CMEs collide with the Earth’s magnetic field and atmosphere and can stir up electromagnetic storms in the Earth’s magnetosphere. These geomagnetic storms can result in the Northern Lights but also disrupt satellite-based navigation, communications, air travel, power grids and even pipelines. A geomagnetic storm in March 1989 shut down the Hydro-Quebec electric grid in Canada, leaving people without electricity. Continue reading

Category: Meteorology, Phenomena

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Are ‘atmospheric rivers’ and the ‘Pineapple Express’ related?

Last week, central and southern California got hit with a substantial rain event, welcome news for a severely drought-stricken area that has not seen heavy rains in many months.

A high-profile element of the storm system that affected the region was a so-called “atmospheric river,” or the local variant of this feature sometimes known as the “Pineapple Express.”
Continue reading

Category: Meteorology, Severe Weather

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