A
dry line (also called
a dew point line, or
Marfa front) is an imaginary line across a continent that separates moist air from an eastern body of water and dry desert air from the west. One of the most prominent examples of such a separation occurs in central
North America, especially Texas, Oklahoma, and Kansas, where the moist air from the
Gulf of Mexico meets dry air from the desert south-western states. The dry line is an important factor in
severe weather frequency in the
Great Plains of
North America. It typically lies north-south across the
High Plains states in the warm sector of an
extratropical cyclone and stretches into the
Canadian Prairies during the spring and early summer. The dry line is also important for severe convective storms in other regions of the world, such as northern
India.