CEDAR RAPIDS, Iowa (KCRG) - Do you know what causes a long stretch of dry, sunny weather? How about what brings rain and storms to Eastern Iowa? It all comes down to low and high-pressure systems. You may hear these terms a lot and the simple definition is that they are both large-scale circulations of wind that cause different types of weather.
We can tell where these are located by analyzing a map of sea level pressure. Pressure is the force exerted on the Earth from the air above. Sea level pressure is used to ignore the different altitudes in areas across the United States. This makes it easier to compare the pressure differences from one place to another.
Meteorologists draw isobars, or equal lines of pressure, to show where the highest and lowest pressures are located. High pressures are associated with warming temperatures and clear skies. Low-pressure systems bring clouds, rain and sometimes thunderstorms.