As any computer systems professional knows, the “leading edge” is a moving target. When the system belongs to LLNL’s National Atmospheric Release Advisory Center (NARAC) — the DOE’s premier atmospheric transport and dispersion simulation facility — ensuring the reliability of core operational systems requires thoughtful consideration of new technology alongside evolving needs. NARAC’s software development team continually evaluates current capabilities and weighs appropriate solutions to meet NARAC’s critical national and international missions. The team is moving to a web-based technology stack, leveraging the stability of many open-source tools.