(WGHP) – The National Weather Service is forecasting at least 97 major cities to reach dangerous levels of heat one or more days this week. 

It’s all thanks to what some are referring to as a “heat dome” over the central United States. Triple-digit heat is likely for the next several days as a high-pressure system parks itself over the country, steering tropical systems and marking yet another heat wave for millions. 

What causes a “heat dome”? 

According to NOAA, high pressure can act like a dome, trapping heat at the surface and favoring the formation of a heat wave. When the heat is trapped it can sometimes be referred to as a “heat dome”.

Usually, when this occurs, it’s because a strong high-pressure system combines with influences from La Nina, creating areas of sweltering heat that gets trapped under the high-pressure “dome”. 


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In school, we were taught to associate high pressure with “happy” weather; however, this week the high pressure will be bringing scorching weather to several states in the central U.S. 

Kansas, Oklahoma, Texas, Nebraska, Missouri and Arkansas are just some of the states that are forecast to reach the triple digits. 

How is the “heat dome” influencing movement in the tropics? 

According to NOAA, global winds are what steer tropical systems such as hurricanes and tropical storms. The prevailing winds that surround a hurricane are what help steer the system in a particular direction. 

Right now, the majority of the United States is parked under a strong high-pressure system. The winds around high-pressure move clockwise. 

Since the overall wind pattern surrounding the United States is clockwise, Potential Tropical Cyclone 9 in the Gulf will be moving almost due west because of the placement of the high-pressure system to its north. 


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The dominating high-pressure system or “heat dome” over the continental United States is also steering Hilary through California and the West Coast

Hilary’s movement was almost parallel to the steering winds of the high-pressure system. The “heat dome” is what allowed Hilary to stray from the typical east-to-west movement and move northward. 

This upper-level pattern is also part of the reason California observed their first direct hit from a tropical storm since September 1939.