How lightning strikes can improve storm forecasts
https://www.sciencedaily.com/releases/2016/11/161111094820.htm
Real-time lightning observations could significantly improve forecasts of large storm events, say scientists. Apart from ground stations, weather forecasts are heavily dependent on weather satellites for information to start or "initialize" the numerical weather prediction models that are the foundation of modern weather prediction. What's missing is accurate, real-time information about air moisture content, temperature and wind speed in places where there are no ground stations.
University of Washington researchers have been tracking global lightning from the ground for more than a decade. Lightning is not only about public safety -- lightning strike data have recently been introduced into weather prediction, and a new UW study shows ways to apply them in storm forecasts.
"When you see lots of lightning you know where the convection, or heat-driven upward motion, is the strongest, and that's where the storm is the most intense," said co-author Robert Holzworth, a UW professor of Earth and space sciences. "Almost all lightning occurs in clouds that have ice, and where there's a strong updraft."
The recent paper, published in the American Meteorological Society's Journal of Atmospheric and Oceanic Technology, presents a new way to transform lightning strikes into weather-relevant information. The U.S. National Weather Service has begun to use lightning in its most sophisticated forecasts. This method, however, is more general and could be used in a wide variety of forecasting systems, anywhere in the world. The authors tested their method on two cases: the summer 2012 derecho thunderstorm system that swept across the U.S., and a 2013 tornado that killed several people in the Midwest. "Using lightning data to modify the air moisture was enough to dramatically improve the short-term forecast for a strong rain, wind and storm event," said first author Ken Dixon, a former UW graduate student who now works for The Weather Company. His simple method might also improve medium-range forecasts, for more than a few days out, in parts of the world that have little or no ground-level observations.
"When you see lots of lightning you know where the convection, or heat-driven upward motion, is the strongest, and that's where the storm is the most intense," said co-author Robert Holzworth, a UW professor of Earth and space sciences. "Almost all lightning occurs in clouds that have ice, and where there's a strong updraft."
The recent paper, published in the American Meteorological Society's Journal of Atmospheric and Oceanic Technology, presents a new way to transform lightning strikes into weather-relevant information. The U.S. National Weather Service has begun to use lightning in its most sophisticated forecasts. This method, however, is more general and could be used in a wide variety of forecasting systems, anywhere in the world. The authors tested their method on two cases: the summer 2012 derecho thunderstorm system that swept across the U.S., and a 2013 tornado that killed several people in the Midwest. "Using lightning data to modify the air moisture was enough to dramatically improve the short-term forecast for a strong rain, wind and storm event," said first author Ken Dixon, a former UW graduate student who now works for The Weather Company. His simple method might also improve medium-range forecasts, for more than a few days out, in parts of the world that have little or no ground-level observations.
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