Recent decades have witnessed remarkable improvements in weather forecasting. Midlatitude weather, which encompasses a significant portion of the world's population, can now be forecasted with reasonable accuracy up to seven to ten days in advance. This is a significant leap from 30 years ago when a seven-day forecast possessed the accuracy of what a four-day forecast did then.

These advancements can be attributed to better computational capabilities and the availability of new, more detailed data. However, the accuracy of forecasts diminishes as the prediction period extends, with large-scale weather systems like storm cyclones being predictable about seven days in advance, while more localized phenomena such as thunderstorms present a much shorter prediction window.

Understanding the Limits of Predictability
The intrinsic limit to weather predictability has been a subject of scientific inquiry since the 1960s. Dr. Riemer emphasizes that, despite improvements, there exists a natural boundary to forecasting accuracy.

"Research has repeatedly reached the same conclusions: We can predict the weather up to 14 days in advance at best," Riemer explains. This limitation is largely due to the chaotic nature of the atmosphere, where initial condition errors play a significant role in forecasting reliability. The team's research suggests that by reducing these initial uncertainties by 80 to 90 percent, the forecast period could be extended by an additional four to five days, approaching the natural predictability limit.

The Butterfly Effect and Weather Forecasting
The butterfly effect, a phenomenon where small changes in initial conditions can lead to vastly different outcomes, is a significant factor in the predictability of weather. This effect, which becomes more dominant as forecast periods extend, underscores the challenge of predicting specific weather events, such as thunderstorms, with high precision over long periods. According to Riemer, addressing the butterfly effect requires a focus on large-scale atmospheric conditions initially, before the more unpredictable, localized effects take precedence.

Future Directions and the Role of Atmospheric Observation
Improving weather forecasts to their maximum potential will require an increased focus on atmospheric observation. Dr. Riemer advocates for intensified observations and measurements, possibly with the assistance of satellite technology, to enhance the initial conditions for forecasting models. This approach could significantly reduce the uncertainty in weather predictions, pushing us closer to the intrinsic limit of predictability.

In conclusion, while the quest to extend the accuracy of weather forecasts faces natural limitations, the potential for improvement remains significant. Through enhanced computational models, better initial condition data, and a deeper understanding of atmospheric dynamics, the future of weather forecasting looks promising. As the research by Dr. Riemer and his colleagues suggests, we may soon be able to extend reliable weather forecasts further into the future, providing valuable time for preparation and mitigation in the face of extreme weather events.

Research Report:The Transition from Practical to Intrinsic Predictability of Midlatitude Weather

Related Links
Dynamic Meteorology group at the JGU Institute of Atmospheric Physics
Earth Observation News - Suppiliers, Technology and Application