ProbSevere Single Site Radar vs. MRMS

The ProbSevere model utilizes Multi-Radar Multi-Sensor (MRMS) data for tracking storms using composite reflectivity as well as maximum expected size of hail (MESH) as a predictor within the model.  When displaying ProbSevere data on single site radar reflectivity, the contours can at times be slightly displaced from the single site radar due to updates to the single site radar data that are not yet ingested within the MRMS data.  The displacement is small and it is still clear which storm a given contour is associated with, but it is something users need to be aware of.  Below are two images with ProbSevere contours overlaid on MRMS (Figure 1) composite reflectivity and KCYS 0.5 degree tilt reflectivity (Figure 2).  The displacement typically only lasts for one to two ProbSevere valid time(s).

Figure 1.  NOAA/CIMSS ProbSevere and MRMS Composite Reflectivity valid at 2204 UTC 5 May 2014.  Notice how the ProbSevere contour very closely matches the MRMS reflectivity.

Figure 2.  NOAA/CIMSS ProbSevere and KCYS 0.5 degree tilt reflectivity, valid at 2204 and 2206 5 May 2014, respectively.  Notice how the ProbSevere contours are slightly displaced from the KCYS storm radar reflectivtiy, because the local radar updated at 2206 UTC.  By 2208 UTC, the ProbSevere contours matched the KCYS reflectivity as the MRMS had ingested the updated KCYS data (not shown).

-Sieglaff