Wildfires in California, flooding along the Eastern Seaboard, tornadoes in Iowa. Confused by this week's weather? Meteorologists say the jet stream is to blame. The jet stream, an air current that encircles the Earth, has adopted an "extreme" pattern that has surprised even experienced meteorologists, The Washington Post reports. "The jet stream is contorting into these extreme loops both sharply towards the poles with ridges of high pressure and dips to the equator with troughs of low pressure,'' said Jeff Masters, co-founder of Weather Underground in Ann Arbor, Michigan.