An intense and nearly historic weather pattern is cooking much of America under a dangerous heat dome this week with triple-digit temperatures in places that haven't been so hot in more than a decade.

Philadelphia is aiming for a high of 100 today, which would mark the first time since July 7, 2012. Heat index values could reach as high as 110 by late afternoon. Along the immediate coast it'll be a bit cooler but even inland sections of shore towns may reach over 100 on the heat index.