Extreme winter weather conditions,including crippling snow and ice storms and deadly cold waves,affect parts of the United States every winter. To anticipate these events, forecasters look for certain large-scale weather patterns that can sometimes signal the arrivalof extreme winter weather conditions. (MORE: ) Here are a few of the weather patterns to watch for this winter. 1.) East Coast Snowstorm Pattern When examining the potential for a blockbuster East Coast winter storm,meteorologists monitor an index called the North Atlantic Oscillation...