Weather Prediction: 1 to 10 days

Most weather forecasts offered by the news media cover some part of the 1- to 10-day period. To produce these outlooks, forecasters examine the results from sophisticated models that simulate the weather up to 16 days out.


How many days into the future can we accurately predict weather?Despite their invaluable role in forecasting, computer models are still unable to depict many aspects of day-to-day weather. NCAR scientists explore the limits of predictability and how those limits can be extended, as well as how and when forecasters should go beyond model guidance.

One example of NCAR's push to better predict weather on this scale, is its participation in THORPEX, a long-term research program organized under the World Meteorological Organization's World Weather Research Program. THORPEX research seeks to accelerate improvements in the accuracy of high-impact, 1-14 day weather forecasts for the benefit of society, economy and environmental stewardship. THORPEX seeks to reduce and mitigate the effects of natural disasters on society by transforming timely and accurate weather forecasts into specific and definite information in support of decisions that produce the desired benefits.

Precipitation is a key element in weather forecasts. As part of the U.S. Weather Research Program, NCAR is working to improve forecasts of rain and snow, particularly in the situations where they matter most, such as a hurricane landfall. Among other findings, the team has gained new insight into repetitive summertime rainfall that can inundate parts of the United States over several days. Some of these multiday episodes appear to be sustained by processes yet to be depicted in models. This work is now being extended to other parts of the globe at risk from similar summertime episodes of heavy rain.

An improved forecasting model is under development by NCAR and collaborators. The Weather Research and Forecasting Model (WRF) bolsters understanding and prediction and promotes closer ties between researchers and forecasters. The WRF model is a community model, and as such, its code can be downloaded from the WRF website, and developed by researchers all over the world. This has lead to many exciting developments by researchers across the world, and even to 2 major physics cores for the model, the WRF-ARW (a version aimed at advanced research & development needs) and WRF-NMM (a version aimed predominanatly at the needs of operational forecasters).