The high heat here in the PNW over the next few days is caused by a combination of factors, including atmospheric waves that have created and inland high pressure system, an off shore low pressure area, and “Santa Ana” like winds.
I live east of the Cascade mountain range, with a line of volcanic peaks to my west.
Even though I am at 3,100 feet elevation, this is high desert – where we normally have hot and dry summers.
By comparison, west of the Cascades is more humid and cooler, and typically cooled by breezes blowing in from the ocean.
But when a high pressure system is here, inland, and low pressure is off shore, winds to blow from the east to the west. As of right now, the winds are already blowing out of the east towards the Cascades.
This has two effects – the warmer air from inland heads west, but as it crosses the Cascade mountains it forms a down slope wind that “piles up the air” causing compression and increasing air pressure. When this air mass “piles up”, the air becomes warmer in a process called adiabatic heating.
This type of wind event occurs throughout the world. This week it is occurring along much of the U.S. west coast, with winds crossing from the east over the Cascades and the Sierra-Nevada mountain range.
Around the world there are what are called “down slope winds”, and they have unique names wherever they occur in their region. Here in North America there are two general areas of these down slope winds. On the eastern slope of the Rocky Mountains in Alberta, Montana, Wyoming and Colorado, they are called Chinook winds. And in Southern California they are called the Santa Ana winds.
Source: All About The Santa Ana Winds
News reports say the specific cause is “human induced climate change” but that is an exaggeration. There are multiple causes occurring simultaneously, including climate changes. This professor of atmospheric sciences notes, instead of 111 or 112 degrees F, climate change may push this to 113 degrees F. Climate plays a role, he says, but is not the predominant cause of this regional heat event. He further explains the downslope heating effects in this blog post.
We are looking at a combination of natural events that are unusually occurring simultaneously, coupled with small effects from climate changes.
Media and activists (who are sometimes scientists) ignore the complexity of the event and focus on those aspects that further their propaganda messaging to encourage you to adopt their agenda.
Reminder: I am a brain injured idiot with, in this case, a little relevant experience. I make observations and ask stupid questions. As to relevant experience, I have an FAA pilot certificate and study meteorology as a hobbyist.