Probability of Severe Weather (IMAGE) Northern Illinois University Caption A graphical depiction of probabilities for severe U.S. weather by storm cluster type following significant Madden-Julian Oscillation fluctuations that have moved into the Pacific Ocean. Credit Douglas E. Miller, Northern Illinois University Usage Restrictions Please credit. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.