Weather forecasts influence daily decisions, from planning commutes to scheduling activities, providing nearly $125 billion in annual benefits to American households. More broadly, NOAA weather data supports key sectors of the nation’s economy, including agriculture, aviation, energy and retail, contributing billions in economic value. Forecasts are also essential for protecting lives and reducing property damage. For example, National Hurricane Center forecasts have helped avoid billions in emergency response costs and losses. The immense value of accurate weather information for Americans is supported by advanced technologies, including sophisticated forecast models and Earth-observing satellites.
Left: A farmer checks on the status of his corn April 23, 2020, in Winston County, Mississippi. He was able to get his corn planted in brief windows between rains. Credit: MSU Extension Service/Kevin Hudson.
Right: Accurate weather data is critical to U.S. military operations. For example, wind, precipitation, and fog can create dangerous conditions for helicopter takeoffs and landings. Credit: Mass Communication Specialist 3rd Chris Cavagnaro, U.S. Navy/Released.
Numerical weather prediction models provide the foundation for reliable forecasts by simulating atmospheric processes. They incorporate observations from satellites, weather balloons and surface stations to set the initial state of the atmosphere, providing a realistic starting point for predicting future weather. Operational forecasters at the National Weather Service (NWS) then refine this model output using their expertise and additional data to deliver the trusted forecasts, alerts and warnings that Americans rely on.
An AWIPS (Advanced Weather Interactive Processing System) workstation at the NOAA National Weather Service (NWS). AWIPS is the computer system used by NWS to process, analyze, and display all types of weather data for forecasting and issuing warnings. Credit: NWS Morristown, Tennessee Weather Forecast Office.
Polar-orbiting low Earth orbit (LEO) satellites are the backbone of global weather forecasting models, providing more than 80% of the data used in numerical weather prediction models for 3-to-7-day forecasts. Some of the most impactful data come from LEO sounding instruments (“sounders”), including the Cross-track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS) onboard NOAA’s Joint Polar Satellite System (JPSS). These instruments measure the intensity of radiation in the atmosphere to show how temperature and moisture vary with height. These factors are important for understanding and predicting storm development.
CrIS and ATMS work together to create detailed three-dimensional profiles of atmospheric temperature and moisture. CrIS measures infrared radiation in cloud-free regions in 2,211 spectral channels. ATMS complements CrIS by measuring microwave radiation in 22 channels. Because microwave signals can pass through clouds, ATMS provides important data in cloudy areas that infrared instruments like CrIS cannot observe. For this reason, weather prediction models typically use data from both instruments. Credit: The COMET Program, University Corporation for Atmospheric Research (UCAR).
While ATMS and CrIS will continue to provide critical data into the 2030s, NOAA is already planning the next generation of LEO satellites to improve weather forecasting and disaster response. A significant challenge is determining ahead of time which measurements, orbital paths and mission configurations will deliver the most value. To help answer this, researchers use Observing System Simulation Experiments (OSSEs) to estimate the impact of new observations before they are actually collected.
OSSEs are advanced computer simulations that use synthetic observations to evaluate the benefits of new observations without needing to build and launch satellites. This cost-effective approach helps NOAA and its partners prioritize technologies that improve forecast accuracy and public safety. Many organizations across government, academia and industry, including NOAA, NASA and the National Laboratories, use OSSEs to test and refine observing systems and guide investment decisions.
As part of NOAA’s plan for next-generation LEO sounders, scientists at NOAA and NASA conducted an OSSE to measure the impact of placing ATMS- and CrIS-like instruments in a new early morning orbit. This orbit would help fill a potential future gap in LEO coverage between the mid-morning orbits of EUMETSAT Metop satellites and the early afternoon orbits of JPSS satellites. The results showed that adding data from this extra orbit into an operational weather model led to clear improvements in global weather forecasts, as shown in the figures below.
These figures show the spatial distribution of Forecast Sensitivity to Observation Impact (FSOI) for ATMS (top) and ocean-only CrIS (bottom) instruments within an OSSE experiment simulating early morning orbit (0530 UTC) from June to September 2020. FSOI quantifies how much an observation improves or worsens a weather forecast when it is assimilated into a numerical weather prediction model. The color scale represents the change in forecast error, where negative values (blue) indicate a reduction in error and positive values (yellow/orange/red) indicate an increase in error. The prevalence of blue shading across both plots demonstrates that the addition of these instruments in the new orbit improves forecast accuracy across significant portions of the globe. Credit: Privé, N.C., et al., CC BY 4.0.
Evaluation tools like OSSEs allow NOAA to assess the benefits of new observing systems early in the design process, helping prioritize technologies that deliver tangible public benefits. These simulations provide a cost-effective, proactive approach to satellite mission development by enabling scientists to test new concepts, explore system configurations and quantify potential forecast improvements before systems are built and deployed.
More on this topic can be found in Feature 4 of the 2025 LEO Science Digest, Designing Next-Generation Observing Systems to Support Better Weather Prediction. Released each January, the Digest highlights innovative research and real-world applications of LEO satellite data, showing how these observations enhance weather forecasting, improve environmental monitoring, support disaster response and benefit the nation’s economy.