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The National Weather Service (NWS) Real-Time Mesoscale Analysis (RTMA) has been developed to provide a national standard Analysis of Record (AoR) for large scale verification and bias-correction efforts. The RTMA and related Un-Restricted mesoscale Analysis, or URMA has been operational since 2006 with frequent upgrades. The NWS AoRnow includes many surface variables, for domains across the U.S., and will be expanded in coming years to a 3-D cube of atmospheric variables at the surface and aloft. The AoRhas been a very challenging project, with issues such as steep slopes and extreme variability of weather in complex terrain, ocean/land interface complexity, choosing a quality first guess field, eliminating obviously erroneous observations, and other issues. Of particular note for the fire community, has been the challenge of generating an accurate relative humidity analysis in complex terrain. Changes are planned with coming updates to better analyse atmospheric moisture.


The role of Air Resource Advisors (ARAs) for wildland fire operations has been steadily increasing. As ARA dispatch activity has increased, interaction with local NWS offices has also increased, and familiarity is growing about ARAs, and air quality issues. In the SE CONUS a long history of impactful smoke issues has led to the development of specialized products, such as the Atmospheric Dispersion Index (ADI), or Low Visibility Occurrence Risk Index (LVORI), which the NWS can calculate and provide to the fire community. These efforts have largely focused on roadway safety issues due to reduced visibility, while in the western CONUS, Alaska, etc., the focus has been on health impacts of smoke to populations and communities. The NWS Missoula has led in the development of a more uniform approach to support for ARAs from NWS field offices.

This seminar was part of the Missoula Fire Sciences Laboratory 2019-2020 Seminar series.

Media Record Details

Nov 14, 2019
Chris Gibson, Ryan Leach

Cataloging Information

Fire Behavior
Fire Prediction

NRFSN number: 20501
Record updated: