Category Archives: Phenomena

How is the atmosphere retained above the Earth?

The atmosphere is actually a fluid. Like water, the pressure at the bottom of a deep column of fluid is larger than the pressure near the top of the column.

Fluids move in response to differences in pressure (the pressure gradient force), always flowing from high toward low pressure. In fact, the wind is driven by pressure differences measured in the horizontal directions. Therefore, the air near the ground (at the bottom of the deep atmosphere) is compelled to move upward toward lower pressure above. Continue reading

Category: Meteorology, Phenomena

Comments Off on How is the atmosphere retained above the Earth?

What is El Niño and does it affect Wisconsin?

El Niño is a combined atmosphere/ocean circulation anomaly in the tropical Pacific Ocean in which unusually warm surface water extends westward from the coast of Peru into the mid-Pacific. One is predicted to develop this winter, which may impact our winter weather.

The warmer than normal waters support persistent tropical thunderstorms in that same region — where such storms are ordinarily rare. Continue reading

Category: Meteorology, Phenomena, Seasons

Comments Off on What is El Niño and does it affect Wisconsin?

Is warmer air ‘heavier’?

We are now in the heart of the baseball season and even the casual fans begin to tune in a bit more regularly to the summer game. One of the long-standing pieces of baseball wisdom suggests that the heat and humidity of oppressive summer heat waves render the air “heavy” and lead to a decrease in offensive power, particularly in home runs.

The veracity of this “wisdom” is testable. Continue reading

Category: Meteorology, Phenomena

Comments Off on Is warmer air ‘heavier’?

Will the recent volcanic eruptions in Hawaii lead to a change in global weather patterns?

While the recent Hawaiian eruptions are impacting the weather and air quality of the immediate area, they are not likely to have a global impact nor to affect Wisconsin’s weather.

The reason is that the ash cloud debris, while reaching 30,000 feet, has remained in the troposphere, the layer where local weather occurs. To have a global impact, the volcano must eject debris into the stratosphere. There it can last for a couple of years and spread over the entire globe. By the ash reaching only into the troposphere, it can stay airborne for no more than a week due to precipitation processes, wind and gravity. Continue reading

Category: Meteorology, Phenomena

Comments Off on Will the recent volcanic eruptions in Hawaii lead to a change in global weather patterns?

What was the ring around the sun last week?

Last week there was a ring around the sun for much of the day. This ring is called a halo and is caused by ice crystals interacting with sunlight.

A halo is a whitish ring that encircles but does not touch the sun. It can also have some color; the most discernible is a faint red tint around the inside of the halo. It is an optical phenomenon that owes its existence to the bending of light by ice crystals, much like the “rainbow crystals” you may hang in your sunlit windows. Continue reading

Category: Meteorology, Phenomena

Comments Off on What was the ring around the sun last week?