 Wake lows form due to adiabatic warming in the wake of mature squall lines at the back edge of their rain shields , where evaporative cooling is unable to offset warming due to atmospheric subsidence , or downward motion . They can be caused by gravity waves which duct through boundary layers which are deep and cold to the north of a weather front . As with mesoscale high @-@ pressure areas behind a squall line , when new thunderstorm development stops along the squall line , the wake low will weaken as well . Clearing conditions will accompany the wake low , due to the descending warm air mass associated with the feature . Within the United States , these systems have been observed to form in the Mississippi river valley , Southeast , Florida , and Great Plains . 
