What is a jet stream?

The strongest jet streams are the polar jets, at around (23,000–39,000 ft) above sea level.

People cool off at Keller Fountain in SW Portland on a hot day, July 1, 2014 (KOIN 6 News)

Toasty temps bake Oregon

The summer heat and the lack of rain continue for the next few days, with temperatures topping out near 90.