Extratropical Cyclones Forming East of the Rocky Mountains

Edition 1 - Example of Rocky Mountain Cyclone National Radar of the April 2001 Cyclone - Hourly images of national radar from 10 to 12 April 2001 show the typical precipitation pattern associated with Rocky Mountain cyclones. Early on 11 April, a line of showers and thunderstorms, associated with the cyclone cold front, extends from Iowa to Texas. Wrap around precipitation is present in eastern Colorado. As the cyclone evolves and migrates northeastward, precipitation continues to wrap around the surface low leading to heavy snow in the northern and central plains. Thunderstorms that develop along the cold front and sweep across Missouri, Illinois and Indiana resulted in severe conditions including tornadoes, large hail and damaging winds.