NOAA develops decision support systems to aid homeland security decision makers in the event that harmful toxic materials are released to the atmosphere. Specifically, NWS Forecast Offices and the NWS-NCEP Hydro-meteorological Prediction Center provide dispersion model forecasts driven by NCEP Numerical Weather Prediction (NWP) models to emergency response managers. In addition, NCEP NWP predictions are made available to the Department of Homeland Security Inter-Agency Modeling and Atmospheric Assessment Center and the DOD Defense Threats Reduction Agency to drive their dispersion models. The atmospheric planetary boundary layer (PBL) height is a critical parameter for dispersion decision support tools. Accurate assessment of boundary layer information at finer scales should improve the Nation's ability to assess the effects of a toxic release. This proposal seeks to use recent NASA satellite technologies and surface based measurements to demonstrate a Real-Time Mesoscale Analysis (RTMA) of PBL information for use by plume dispersion modelers. Specifically, PBL height products derived from NASA GPS instruments aboard several satellites (COSMIC, GRACE, CHAMP) will be assimilated along in the NCEP 5 km RTMA. Ground based lidar measurements from the NASA MPLNET as well as CALIPSO will be used to evaluate the RTMA. We will also leverage the NOAA funded NCAS and other ground lidars for evaluation. An additional dispersion related product, the atmospheric stability, will be computed using the existing RTMA analyses along with the proposed PBL products. The stability analysis can help emergency managers identify areas conducive for weak dispersion which would be vulnerable to high toxic pollutant concentrations if a release did occur. These results and user feedbacks will be compiled into a report that assesses the improved high resolution analysis on dispersion forecasts. An end-to-end work plan will be employed to outline the transition from NASA Earth Science research into NOAA applications.