Why & how does it work? High pressure & extreme heat

A high-pressure system in the upper atmosphere is to blame for the extreme heat across the Northwest over the weekend and at the start of the week.

Prolonged extreme temperatures are often due to the infamous dome of high pressure, which could stay in the same place for several days to a couple of weeks. But do you know how these domes work? Why do these pesky high pressures often bring so much heat for such an extensive time? We got the answer for you!