[--MAIN HOME--] [--ALL HABYHINTS--] [--FACEBOOK PAGE--] OUTFLOW BOUNDARY CHARACTERISTICS METEOROLOGIST JEFF HABY An outflow boundary is a mesoscale cold front. Because of the small spatial area they encompass, the forecast models have difficulty integrating them into the output. Outflow boundaries primary originate from thunderstorms. Colder mid-level air is brought down to the surface in the downdraft of a thunderstorm. An outflow boundary is most well defined when it occurs out ahead of a squall line or thunderstorm complex. The downdrafts from several thunderstorms merge into one outflow boundary. The outflow boundary causes rising air along the edge. The warm and moist air rises when it converges into the denser outflow boundary air. An outflow boundary can be a focusing mechanism for new thunderstorms, even a day after the outflow boundary has formed. Knowing the position of the outflow boundary can help a forecaster pinpoint the location storms will form the next day. If the atmosphere is unstable, the outflow boundary can act as the trigger mechanism for deep convection (thunderstorms).