This story has been updated to include additional information.
If you’re in New York, you might be reaching for a jacket. In Texas, the air conditioner is running nonstop. Meanwhile, one part of the U.S. is stuck in early spring chill, and another faces brutal storms.
The reason isn’t random — it’s a stalled pattern high above the country that’s locking weather into place.
A large-scale atmospheric pattern known as an Omega Block is helping organize a busy and highly divided weather setup across the United States this week, supporting severe thunderstorms in the Plains, mountain snow in the West and steady rain along parts of the East Coast.
The pattern, named for its resemblance to the Greek letter Ω in the jet stream, is slowing the typical west-to-east movement of weather systems. That slowdown is allowing multiple fronts and storm systems to linger and repeatedly impact the same regions.
