<P> After the passage of the cold front, the sky usually clears as high pressure builds in behind the system, although significant amounts of cumulus or stratocumulus, often in the form of long bands called cloud streets may persist if the air mass behind the front remains humid . Small and unchanging amounts of cumulus or cirrus clouds in an otherwise clear sky are usually indications of continuing fair weather as long as the barometric pressure remains comparatively high . </P> <P> A cold front commonly brings a narrow band of precipitation that follows along the leading edge of the cold front . These bands of precipitation are often very strong, and can bring severe thunderstorms, hailstorms and / or tornadoes . In the spring, these cold fronts can be very strong, and can bring strong winds when the pressure gradient is higher than normal . During the winter months, cold fronts sometimes come through an area with little or no precipitation . Wider rain bands can occur behind cold fronts which tend to have more stratiform, and less convective, precipitation . These rainstorms sometimes bring flooding, and can move very slowly when the storm steering it is strong and embedded within a meridional flow pattern (with more pole to equator motion rather than west to east motion). In the winter, cold fronts can bring cold spells, and occasionally snow . In the spring or summer in temperate latitudes, hail may occasionally fall along with the rain . If moisture is not sufficient, such as when a system has previously moved across a mountain barrier, cold fronts can pass without cloudiness . </P> <P> Frontogenesis is the process of creating or steepening the temperature gradient of a front . During this process the atmosphere reacts in an attempt to restore balance, the consequence is a circular motion along the front where air is being lifted up, along the cold front and dropping downward, behind the frontal boundary . This is the actual force of upward motion along a front that is responsible for clouds and precipitation . </P> <P> As the temperature gradient steepens during frontogenesis, the thermal wind becomes imbalanced . To maintain balance, the geostrophic wind aloft and below adjust, such that regions of divergence / convergence form . Mass continuity would require a vertical transport of air along the cold front where there is divergence (lowered pressure). Although this circulation is described by a series of processes, they are actually occurring at the same time, observable along the front as a thermally direct circulation . There are several factors that influence the final shape and tilt of the circulation around the front, ultimately determining the kind and location of clouds and precipitation . </P>

What type of weather forms at a cold front