Air mass limit
An air mass boundary is an area in which two air masses of different temperature or humidity meet and neither of the two can displace the other.
Origin and impact
Air mass boundaries are typically 20 to 200 kilometers wide. They arise when warm air ( warm front ) meets cold air ( cold front ). Large amounts of precipitation occur at the air mass boundary, as the boundary often remains locally stable for hours or even days.
In the summer are often raising thunderstorm initiated in the winter for fall. B. on the cold side snow at clear minus degrees, while a few hundred kilometers further it rains at plus temperatures. Air mass boundaries are not always tied to a low pressure area , but small independent lows (marginal lows) can arise at the boundary. In the transition months of spring and autumn , the air mass limits are not so pronounced, which is why extreme weather conditions are not to be expected.