Hey Ray: Atmospheric Rivers
PITTSBURGH (KDKA) - In Pittsburgh, we are not strangers to rivers.
We have three rivers downtown and several more rivers around the region. Our rivers, however, move water on the ground.
Today we are going to explore intense amounts of moisture moving in the sky.
Those are called atmospheric rivers!
These are long, narrow areas of intense moisture in the atmosphere. This moisture usually streams out of tropical areas and onto land.
Atmospheric rivers average 200-400 miles wide. Compared to other weather systems, this is quite narrow. The atmospheric river pushes moisture toward land, where the topography forces it upward.
The moisture cools and condenses leading to areas of intense rainfall or snow. The heavy precipitation results in flooding potential and even landslides. They tend to impact the Western United States.
Yes, we have rain and storms and snow that all involve the sky or atmosphere, so why does there need to be the term "atmospheric river" to describe heavy rain?
According to the National Weather Service, just an average atmospheric river carries water vapor that is about the same as the average flow of water at the mouth of the Mississippi River.
That makes it a fair comparison to a river.
When atmospheric rivers become exceptionally strong, they can have 15 times that amount!
Not all atmospheric rivers are bad, though.
The National Weather Service says they are key to the global water cycle. They do bring beneficial rains and snowpack. These rivers in the sky happen in many locations across the world.
There is an atmospheric river that transports moisture from near the Hawaiian Islands to the west coast of the United States. You may have heard of that one before.
It is called the Pineapple Express...It is probably the tastiest-named atmospheric river, too!
