NEW: Central US Winter Storms February 2021 UPDATED: Arctic Amplification UPDATED: Winter Storm Risk Increase Tweet: Plot of annual Atlantic Multi-decadal Oscillation index by Philip Klotzbach on Twitter Original tweet: Plot of annual Atlantic Multi-decadal Oscillation index using @ColoradoStateU definition since 1878. Trending negative over past few years. Go to Site Related Climate Signals Intense Atlantic Hurricane Frequency Increase