Author Archives: WeatherGuys Editor

How is visibility distance evaluated for a weather map?

The weather observing stations of the National Weather Service operate in fully automatic mode and have sensors that measure visibility.

These instruments sense the forward scattering characteristics of light to measure the extinction coefficient of a high intensity beam directed at a volume of air close to the sensor. This provides an accurate measurement over a range of visibilities. The use of light within the visible spectrum also allows the sensor to simulate human perception of visibility. Continue reading

Category: Meteorology

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You thought Wisconsin’s winter was warm? Wait till summer

Changes in the weather patterns that brought record-breaking warm temperatures to the Madison area this winter might also mean that a warmer-than-usual summer lies ahead.

There’s a fair chance that temperatures could rise above normal in June, July and August, and even into early fall, climate scientists say. Continue reading

Category: Climate, Seasons

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How did this mild winter compare to previous such years?

We are now past the end of the meteorological winter, which consists of the months of December, January and February.

This season has been a remarkably mild one for most of its duration. With the exception of a week of desperate cold in mid-January, there was hardly any cold air to speak of in southern Wisconsin all winter. In fact, Madison was 9.5 degrees above normal for December, 3.5 degrees above normal for January (reduced because of the cold snap Jan. 14-21, during which the temperature was 14 degrees below normal!) and 11 degrees above normal for February. Continue reading

Category: Climate, Seasons

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Has there been a sudden stratospheric warming this year?

The stratosphere, which begins approximately 6 miles above the cold poles and 10 miles above the tropics, is where the temperature increases with altitude. Temperatures increase because ozone molecules in the stratospheric ozone layer absorb solar ultraviolet energy within the stratosphere. Air flow in the stratosphere is much less turbulent than in the troposphere. For this reason, jet aircraft pilots like to cruise at stratospheric altitudes so the flight is less bumpy. In polar regions, the top of the stratosphere extends upward to around 30 miles.

The polar vortex is a band of strong winds high in the atmosphere that spins counterclockwise around the North Pole. At the southern edge of the vortex is the polar jet stream, which separates warm air to its south from increasingly colder air to its north. Continue reading

Category: Phenomena, Severe Weather

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What is latent heat?

Since the beginning of the 2023-24 snow season, Madison and Dane County have received approximately 32 inches of snow.

Snow is a form of solid water, and water is the only substance that occurs naturally in all three phases — solid, liquid and invisible gas — in the Earth’s atmosphere. Of course, that means that the 32 inches of snow began as the equivalent amount of water in the invisible vapor (gas) phase before it transformed into solid water. Continue reading

Category: Meteorology, Seasons

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