A prediction lead time of about 2 to 5 weeks is sorely lacking in current forecasting capabilities for severe weather. Atmospheric scientists now demonstrate the ability to make skillful predictions of severe weather across the Plains and southeastern United States, including hail and tornadoes, in that coveted ''subseasonal'' time scale. To do it, they use a reliable tropical weather pattern called the Madden-Julian Oscillation, which can influence weather in distant parts of the Earth.