This session will focus on promising, new sensor and observing technologies, as well as improvements to current operational systems, that hold great potential to advance mesoscale observing systems and are mission-effective, integrated, adaptable, and affordable. In-situ observations of the planetary boundary layer (PBL) and troposphere, on the mesoscale specifically, serve as critical inputs for operational and research weather models for both the weather and water enterprise. Observing system experiments have shown that enhanced observational density in space and time improves mesoscale forecasts. There is a relative scarcity of high-resolution surface and PBL mesoscale observations, which impedes advancements in prediction skill of high-impact and disruptive weather events. Presentations should focus on emerging, innovative technologies and current technology improvements that hold the potential to improve the accuracy, reliability, spatial coverage, cost effectiveness, deployability, safety, and sustainability of mesoscale observations for eventual use by the operational weather and water enterprise including NOAA, the National Mesonet Program, the private sector, and other government sectors. The scope of this session includes weather- and water-related observations from the surface through the troposphere, with emphasis on the PBL, including in-situ surface, profiling, balloon-borne, radar, and airborne and uncrewed systems technologies. Satellite-based sensors are not included in this scope except to calibrate, validate, or integrate with in-situ observations as a secondary objective.  New technologies from the commercial sector and unique observations of opportunity are welcome.