"Heat Dome" That's Been Baking Mexico Spreads To U.S.; Could Impact Rest Of Nation Over The Summer

A schematic of a heat dome over the middle of the
United States. In a heat dome, high pressure
causing sinking air, which ensures strong sun
trapping hot air in place. 

What is known as a "heat dome" - a persistent, torrid high pressure system, has been baking Mexico, Central America and the Caribbean, has been expanding in recent days and weeks to affect the United States.   

Heat domes are fairly common mostly over continents in the summer. But they've been getting more intense with climate change. 

The latest heat dome has been killing people, causing droughts and fires, and also triggering intense storms,  especially along its edges.

Mexico City residents are rationing water as drought dries up supplies. The city could run out of water as early as June 26, even as the region's hoped for rainy season starts about then, according to Axios.

The Mexican heat has been brutal on wildlife, too. Mexico's famous howler monkeys have been dying in the heat. As of Sunday, 157 of the monkeys had succumbed in southern Mexico. An endangered salamander looks like it might go extinct because of the heat. 

All time record high temperatures have been set in parts of Mexico, Belize and other Central American and Caribbean nations. 

 The heat has been making inroads into Florida and Texas in recent days. 

Del Rio, Texas reached 109 degrees last week, setting an all time record high for the month of May. 

As of Sunday, four of Houston's 20 hottest May days since the late 1880s happened this month. 

There's been little relief from the heat at night. Kingsville, Texas recently had an overnight "low" of 84 degrees, the highest low temperature on record in May for anywhere in Texas. 

The heat index in Miami was 112 degrees on both May 18 and 19.  That's only happened once before, in  August of last year. But it's only May, so that episode was especially bizarre.

SUMMER DANGER

All this adds a potentially ominous tone for the summer in the United States. It's inevitable that the heat dome will expand into the  Lower 48 and perhaps southern Canada as we move through June, July and August. 

Most likely, it will persist for a few days over a certain region, then shift to somewhere else and back again.  Given the intensity of the heat dome and climate change, this could lead to dangerous all time record highs at the height of summer. 

An intense heat dome in the Pacific Northwest and southwestern Canada in 2021 led to the all-time record high for  Canada of 121 degrees in Lytton, British Columbia. That town burned down the next day in a wildfire that was greatly accelerated by the heat and drought. 

The 2021 heat wave killed 619 Canadians and dozens of people in the U.S. Pacific Northwest as temperatures climbed into the 110s in many locations. 

We risk a similar disaster this summer, but of course we don't know where yet. 

The summer heat dome could also pretty much park itself over one location for much of the summer, like it did in Mexico this spring. That would cause weeks of record high temperatures, deaths from heat and flash droughts.   

HEAT DOMES, CLIMATE CHANGE AND US 

Heat domes have always been a thing. The intense heat and dust bowl droughts of the 1930s were in large part caused by heat domes. 

Climate change is helping to intensify heat domes, here in North America and in Europe and Asia, where heat waves have killed tens of thousands in recent years. Heat waves are not photogenic like most disasters like hurricanes and tornadoes. But heat is the deadliest type of disaster, so they should be taken more seriously than they are. 

We obviously don't know whether or how much any heat domes will affect us here in Vermont. 

Even in this cool, temperate corner of the world, heat can be dangerous in Vermont. An intense July, 2018 heat wave caused six deaths in Vermont and dozens up in Quebec, for instance. 

Again, because of climate change, I think the all time record high temperature in the Green Mountain State - 105 degrees in Vernon, in July, 1911 - might well be broken within the next decade. I imagine Burlington's all-time high of 101 will be challenged, too.

I'm not saying that will happen this year. I imagine it could, but it's all the roll of the dice. 

Long range forecast call for a hot summer in the United States, with the best chance of persistent heat in the western United States and in New England. 

It's been one of the warmest Mays on record in Vermont. Who knows whether that trend will last through the summer. But I'd bet on at least some brutal heat in the coming months.