Researchers rise to challenge of predicting hail, tornadoes three weeks in advance

People living in Kansas, Nebraska and other states in the Plains are no strangers to tornadoes and hail storms – among the most costly and dangerous weather threats in the United States.

Meteorologists and computer models do a good job forecasting thunderstorm activity up to a week in advance. Scientists can also read long-term, seasonal signals of severe weather months in advance. But there’s a middle ground – a prediction lead time of about 2 to 5 weeks – that’s sorely lacking in current forecasting capabilities.

In a new paper in Journal of Geophysical Research: Atmospheres, Colorado State University atmospheric scientists demonstrate the ability to make skillful predictions of severe weather across the Plains and southeastern United States, including hail and tornadoes, in that coveted 2-to-5-weeks-in-advance period. 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, including the U.S., by sending out powerful atmospheric waves.

“When the Madden-Julian Oscillation is active, it is capable of setting up atmospheric patterns that are favorable for severe weather across the United States over the next several weeks,” explained Cory Baggett, research scientist in atmospheric science and the paper’s lead author. “We have found that an active Madden-Julian Oscillation, which periodically goes around the equator in 30 to 60 days, is a really good source of predictability on these subseasonal time scales.” Atmospheric scientists typically consider “subseasonal” to mean about three weeks to three months in advance.

Read the full Source article, “Researchers rise to challenge of predicting hail, tornadoes three weeks in advance.”