Let's start with the good news: The Lower 48 has reached peak summer, backed by 30 years of seasonal temperature trend data from Bloomberg. 

Now for the bad news: A heat wave continues to set records across the Lower 48, with 150 million Americans under weather alert this holiday weekend. 

Axios outlines the areas where the heat dome will impact the most: 

National Weather Service meteorologist Jenn Varian told Bloomberg that Las Vegas is forecasted to hit a scorching 117F on Sunday into early next week, potentially tying the metro area's all-time high recorded in 2005 and again in 2017.

"Confidence is increasing that this potentially historic heatwave will last several days," the National Weather Service's office in Portland, Oregon, wrote on X, adding temperatures will rise "into the 100s and 110s over much of California and southern Oregon." 

Here are more forecasted highs this weekend (list courtesy of Axios):

This all means that power grids will be under stress this weekend as high temperatures boost air conditioning demand. Bloomberg says that grids in California and Texas should be closely monitored for an elevated blackout risks.