Over the last decade, infusion of new science and technology (S&T) into operations has significantly improved National Weather Service (NWS) forecast and warning lead times, accuracies, and overall product quality. Deployment of the Next Generation Weather Radar (NexRad), Advanced Weather Interactive Processing System (AWIPS), Automated Surface Observing System (ASOS), Geostationary Operational Environmental Satellites (GOES), advanced high performance computing, and computer models, coupled with restructuring of field operations and forecaster training have allowed major improvements in the warning and forecast accuracies and lead times of weather affecting virtually every facet of people’s lives and the economy. For example, tornado warnings, which generally had no lead time in the 1970’s, are now issued with an average lead time of 10 minutes – and as much as 30 minutes lead time in some cases – allowing precious time for people to seek cover; and flash flood warnings have increased from 8 minutes to 53 minutes – giving people nearly 10 times the alert they once had. Over the next decade, further improvements forecast accuracy and other NWS products and services are required. Emergency managers need hours, not minutes lead time to prepare the public for hazardous weather; and businesses need days, not hours advanced notice to prepare for weather changes that will affect their bottom line. To meet these improvement challenges and sustain service excellence to the Nation, the NWS must stay near the cutting-edge of S&T supporting its mission. This Science and Technology Infusion Plan (STIP) defines strategies, objectives, and programs the NWS will pursue to meet operational requirements and exploit scientific opportunities. The STIP is linked to other NWS plans for products and services, operations, infrastructure, the workforce, and information technology--all working together toward NWS and NOAA strategic goals.