What is an omega block? According to Weather.com meteorologist Jonathan Erdman, "if you trace the path of the jet stream across the U.S. from the West to the East, you will trace out the Greek ...

So, if your weather app shows a 30% chance of rain, it means there is a 30% likelihood (roughly one in three) that at least 0.01 inches of rain will fall at that time and location.

The weather service said the tornado warnings were activated by meteorologists who detected cloud rotation — a key indication of a potential tornado spinning — on radar.

A pattern of record-breaking warmth near Iceland is contributing to stormy weather and unusually cool temperatures in the United States this week. An unusual heat dome over the North Atlantic ...