Evaluation of the Real-Time Mesoscale Analysis (RTMA) over complex terrain

The Real-Time Mesoscale Analysis (RTMA) is a high resolution gridded surface analysis currently under development at the Environmental Modeling Center of the National Centers for Environmental Prediction. To support the development of the RTMA, NWS Western Region Scientific Services Division (WR/SSD) has been evaluating the behavior of temperature and dew point temperature analyses along three terrain cross sections. Evaluation sites were chosen based on their proximity to a measurable gradient in terrain elevation and the availability of an atmospheric sounding. By arranging the cross sections based on elevation, we are able to visualize the vertical structure of temperature and dew point temperature of the RTMA within the lowest 2000 m above the surface. Along each terrain cross section, RTMA values are compared to selected objective analysis solutions, nearby mesonet observations, and when available, an atmospheric sounding. Point verification is also conducted by comparing mesonet observations to the nearest RTMA grid point values. Examples from the WR/SSD evaluation will be shown to highlight the performance of the RTMA during several unique weather regimes near Salt Lake City, UT during the 2006/07 winter season.