The subtropical jet stream is a fast-flowing ribbon of air located high in the atmosphere, typically found between 20 and 30 degrees latitude in both the Northern and Southern Hemispheres. It forms at the boundary between warm tropical air and cooler polar air, influencing weather patterns and climate in the regions below. This jet stream can affect storm systems, leading to changes in precipitation and temperature. It plays a crucial role in the movement of weather systems and can impact areas far from its location, making it an important factor in meteorology and climate studies.