Summer has officially returned to Chicagoland, and while there is plenty to love about the city’s favorite season, the summer ...

"When the pressure is high, the air is denser, and the birds’ wings have something to press against. Conversely, in lower air pressure systems, there are fewer molecules of air to press against ...

This process leaves less air, and lower air pressure, near the ground, which creates a centre of low pressure. Stronger divergence can create a stronger low-pressure system.