Colorado terrain field with TITAN storm tracks (magenta) from 1 July 2015 overlaid. 

Based on years of experience in monitoring and studying storms over the Colorado Front Range, we have been cognizant that a large percentage of storms that form over the Rockies quickly dissipate as they move off the mountains onto the plains.  However no quantitative study has been done to document the actual percentage.   Using the radar data and TITAN storm tracks produced in real-time during 2015 demonstration, it was possible to determine this frequency of occurrence.  The figure shows all the TITAN storm tracks on 1 July overlaid onto the Colorado terrain (color-coded, in 400 m increments). On this day, it can be seen that the majority of storms that formed over the mountains dissipated as they moved to the lower terrain of the plains.   Examination of all of the tracks from 1 June – 15 August showed that 91% of the storms that initiated above an elevations of 2600 m dissipated before reaching 1400 m.  Using this information, a predictor field and membership function was added to the Autonowcaster/Trident fuzzy nowcasts and run during the 2016 demonstration.

VDRAS analyses of perturbation temperature (color fill), wind vectors, and rain water mixing ratio at the height 150m above ground valid at 2015071505 UTC (left) and 1h nowcast. 

Along with the Autonowcaster, VDRAS was run over the same domain and the same configuration as in 2015 with an improved surface data assimilation scheme. Our research effort on VDRAS focused on PECAN data analysis and development of model-based nowcast techniques. The figure shows an example of VDRAS analysis (left) and 1h nowcast (right).