Omega Block Setting Up Next Week: What This Means

Time to pull out your Greek alphabet for next week’s weather.

The pattern setting up in the coming days, dubbed an ‘Omega block,’ will make for s-l-o-w moving weather systems. 

So, what exactly is it?

An Omega Block, Explained

Meteorologists aren’t the most creative when it comes to naming things, and this blocking pattern is a prime example.

It gets the name ‘Omega block’ because when you trace the jet stream from west to east while this pattern is in place, you will see the Greek letter omega (Ω). 

This setup blocks the typical east-west flow of the jet stream, like a large rock in a small stream that forces the flow of water around it, as senior meteorologist Jonathan Erdman describes it.

As a result, weather systems will move more slowly for several days, leading to day after day of similar conditions across the country.

The two things we typically watch out for during this pattern are potential flooding and an upside-down temperature pattern. 

Let’s break down who could see what.

Flood Threat

To the west and east of the Omega Block, we typically see low-pressure systems get stuck, causing days of unsettled, rainy weather.

This will be the case across the South next week, where several days of rain and storms could lead to flash flooding, especially in areas hard-hit by drought. 

Cities like Dallas, Houston, New Orleans, Birmingham, Atlanta and Tallahassee should be on alert.

Upside-Down Temperatures

The other signature impact of an Omega block on weather is the upside-down temperature pattern.

The northern half of the block typically sees dry conditions and above average warmth.

We will see this pattern play out nicely next week with parts of the Northern Plains and Upper Midwest forecast to see temperatures soar, while the Southwest and Southeast stay cooler.

On Tuesday, the high temperature in Minneapolis could be over 10 degrees warmer than the high in Albuquerque or Atlanta. 

Caitlin Kaiser graduated from the Georgia Institute of Technology with both an undergraduate and graduate degree in Earth and Atmospheric Sciences before starting her career as a digital meteorologist with weather.com.