Rare ‘Omega Block’ Weather Pattern to Bring Days of Chilly Air to These Cities

By Evan Comen • May 6, 2025

https://climatecrisis247.com/wp-content/uploads/2025/05/omega-map-150x150.png

A rare, persistent weather pattern known as an “omega block” is setting up across the continental U.S. this week. Named for the shape of the Greek letter Ω, omega blocks occur when a ridge of high pressure becomes trapped between two areas of low pressure. The result is a slow-moving and stagnant weather setup that can last for days, bringing prolonged impacts to regions on both sides of the ridge.

DOGE backlash? The Federal Departments Americans Want To Keep
Dying for air? Climate Activism Is Turning Deadly In These Cities

The configuration disrupts the usual west-to-east flow of weather systems, causing weather systems to linger for several days. According to NOAA forecasts, a strong ridge of high pressure has formed over the northern Plains, flanked by two low-pressure systems over the Ohio Valley and the West Coast. Cities in the center of the omega block will experience abnormally high temperatures and dry conditions, while cities on the outside of the omega formation on both coasts will experience cool temperatures and heavy precipitation. A closer look at the data reveals the cities that will be abnormally cool this week.

To determine the cities where it will be abnormally cool this week, Climate Crisis 247 reviewed 72-hour temperature forecasts and historical station-level daily temperature readings from the NOAA. Cities were ranked based on the difference between the forecast average temperature for May 5-7 2025, and the average observed temperature for May 4-6 from 2006 to 2020. Gridded forecast data are from the National Digital Forecast Database, while historical temperature normals are from the Global Historical Climatology Network daily program of the National Centers for Environmental Information. Weather stations were matched to places using nearest neighbor analysis and were limited to cities within 50 miles of the city centroid. Only cities with at least 25,000 residents were considered.

25. Apache Junction, AZ

Photo by Lance Anderson on Unsplash

Forecast average, May 5-7: 65.6°F (-8.2°F below climate normal)
Normal average, May 5-7: 73.7°F (2006-2020)
Total population: 38,855

24. Muncie, IN

Photo by Adam Bouse on Unsplash

Forecast average, May 5-7: 53.1°F (-8.2°F below climate normal)
Normal average, May 5-7: 61.3°F (2006-2020)
Total population: 65,167

23. Cookeville, TN

Photo by Intricate Explorer on Unsplash

Forecast average, May 5-7: 54.6°F (-8.4°F below climate normal)
Normal average, May 5-7: 63.0°F (2006-2020)
Total population: 34,967

22. Phoenix, AZ

Photo by Nader Abushhab on Unsplash

Forecast average, May 5-7: 66.4°F (-8.4°F below climate normal)
Normal average, May 5-7: 74.8°F (2006-2020)
Total population: 1,609,456

21. Chattanooga, TN

Photo by Sarah Swainson on Unsplash

Forecast average, May 5-7: 59.0°F (-8.4°F below climate normal)
Normal average, May 5-7: 67.4°F (2006-2020)
Total population: 181,288

20. Scottsdale, AZ

Photo by Logan Voss on Unsplash

Forecast average, May 5-7: 62.5°F (-8.5°F below climate normal)
Normal average, May 5-7: 71.0°F (2006-2020)
Total population: 240,537

19. Lexington-Fayette, KY

Photo by Cody Nottingham on Unsplash

Forecast average, May 5-7: 54.5°F (-8.5°F below climate normal)
Normal average, May 5-7: 63.0°F (2006-2020)
Total population: 321,276

18. Gadsden, AL

Photo by Paige Bailey on Unsplash

Forecast average, May 5-7: 59.4°F (-8.6°F below climate normal)
Normal average, May 5-7: 67.9°F (2006-2020)
Total population: 33,881

17. Athens, AL

Photo by Pixabay on Pexels

Forecast average, May 5-7: 59.0°F (-8.7°F below climate normal)
Normal average, May 5-7: 67.7°F (2006-2020)
Total population: 26,179

16. Hopkinsville, KY

Photo by KoolShooters on Pexels

Forecast average, May 5-7: 55.6°F (-8.8°F below climate normal)
Normal average, May 5-7: 64.4°F (2006-2020)
Total population: 31,042

15. Henderson, KY

Photo by Griffin Taylor on Unsplash

Forecast average, May 5-7: 54.6°F (-8.8°F below climate normal)
Normal average, May 5-7: 63.4°F (2006-2020)
Total population: 28,166

14. Frankfort, KY

Photo by Tolga Ahmetler on Unsplash

Forecast average, May 5-7: 54.4°F (-8.8°F below climate normal)
Normal average, May 5-7: 63.2°F (2006-2020)
Total population: 28,460

13. Bullhead City, AZ

Photo by Joe Cook on Unsplash

Forecast average, May 5-7: 68.4°F (-9.0°F below climate normal)
Normal average, May 5-7: 77.4°F (2006-2020)
Total population: 41,593

12. Clarksville, TN

Photo by Joetography on Pexels

Forecast average, May 5-7: 56.2°F (-9.1°F below climate normal)
Normal average, May 5-7: 65.3°F (2006-2020)
Total population: 167,882

11. Peoria, AZ

Photo by Star on Unsplash

Forecast average, May 5-7: 64.7°F (-9.3°F below climate normal)
Normal average, May 5-7: 74.0°F (2006-2020)
Total population: 191,292

10. Huntsville, AL

Photo by Alex Loyola on Pexels

Forecast average, May 5-7: 59.2°F (-9.3°F below climate normal)
Normal average, May 5-7: 68.4°F (2006-2020)
Total population: 215,025

9. Prescott, AZ

Photo by Donald Teel on Unsplash

Forecast average, May 5-7: 47.2°F (-9.8°F below climate normal)
Normal average, May 5-7: 56.9°F (2006-2020)
Total population: 46,054

8. Sierra Vista, AZ

Photo by Rô Acunha on Pexels

Forecast average, May 5-7: 54.2°F (-9.8°F below climate normal)
Normal average, May 5-7: 64.1°F (2006-2020)
Total population: 45,212

7. Bowling Green, KY

Photo by Arian Fernandez on Pexels

Forecast average, May 5-7: 55.4°F (-9.9°F below climate normal)
Normal average, May 5-7: 65.3°F (2006-2020)
Total population: 72,385

6. Louisville/Jefferson County, KY

Photo by Miles Manwaring on Unsplash

Forecast average, May 5-7: 54.4°F (-10.1°F below climate normal)
Normal average, May 5-7: 64.5°F (2006-2020)
Total population: 629,176

5. Casa Grande, AZ

Photo by Oliver Hihn on Unsplash

Forecast average, May 5-7: 65.0°F (-10.3°F below climate normal)
Normal average, May 5-7: 75.3°F (2006-2020)
Total population: 55,186

4. Evansville, IN

Photo by Cameron Cox on Unsplash

Forecast average, May 5-7: 54.7°F (-10.6°F below climate normal)
Normal average, May 5-7: 65.3°F (2006-2020)
Total population: 116,906

3. Terre Haute, IN

Photo by Wesley Armstrong on Unsplash

Forecast average, May 5-7: 53.1°F (-10.6°F below climate normal)
Normal average, May 5-7: 63.7°F (2006-2020)
Total population: 58,599

2. Tucson, AZ

Photo by JC Cervantes on Unsplash

Forecast average, May 5-7: 62.0°F (-11.2°F below climate normal)
Normal average, May 5-7: 73.2°F (2006-2020)
Total population: 541,033

1. Palm Springs, CA

Photo by Cody Board on Unsplash

Forecast average, May 5-7: 66.4°F (-11.4°F below climate normal)
Normal average, May 5-7: 77.8°F (2006-2020)
Total population: 44,935

More from ClimateCrisis 247