When cold air overtakes warmer air this is known as a Cold Front. In Northern Hemisphere usually it is oriented NE/SW and moves at a speed of 30-40 knots. Near the front we may find severe weather, generally short lived, with gusty winds and turbulence. Occasionally, lines of thunderstorms or a squall line may develop 50-300 miles ahead of fast moving fronts. The general characteristics of a Cold Front are cumulus clouds, turbulence, showery precipitation, a pressure drop and then rise, temperature drop after frontal passage, wind shift, clearing skies, good visibility, and generally cooler, drier air moving into the area.