<P> A warm front is a density discontinuity located at the leading edge of a homogeneous warm air mass , and is typically located on the equator - facing edge of an isotherm gradient . Warm fronts lie within broader troughs of low pressure than cold fronts , and move more slowly than the cold fronts which usually follow because cold air is denser and less easy to remove from the Earth 's surface . This also forces temperature differences across warm fronts to be broader in scale . Clouds ahead of the warm front are mostly stratiform , and rainfall gradually increases as the front approaches . Fog can also occur preceding a warm frontal passage . Clearing and warming is usually rapid after frontal passage . If the warm air mass is unstable , thunderstorms may be embedded among the stratiform clouds ahead of the front , and after frontal passage thundershowers may continue . On weather maps , the surface location of a warm front is marked with a red line of semicircles pointing in the direction of travel . </P>
<P> A warm front is a density discontinuity located at the leading edge of a homogeneous warm air mass , and is typically located on the equator - facing edge of an isotherm gradient . Warm fronts lie within broader troughs of low pressure than cold fronts , and move more slowly than the cold fronts which usually follow because cold air is denser and less easy to remove from the Earth 's surface . This also forces temperature differences across warm fronts to be broader in scale . Clouds ahead of the warm front are mostly stratiform , and rainfall gradually increases as the front approaches . Fog can also occur preceding a warm frontal passage . Clearing and warming is usually rapid after frontal passage . If the warm air mass is unstable , thunderstorms may be embedded among the stratiform clouds ahead of the front , and after frontal passage thundershowers may continue . On weather maps , the surface location of a warm front is marked with a red line of semicircles pointing in the direction of travel . </P>
with respect to a warm front most precipitation and poor weather is found on the
with respect to a warm front most precipitation and poor weather is found on the
ahead of the front
ahead of the front