Strengths

Unlike the Storm Cell Identification and Tracking (SCIT) and Hail Detection Algorithm (HDA) from the WSR-88D Radar Product Generator (RPG), hail tracks are not centroid based and allow the forecaster to view a single image showing both the location history and the intensity trend of hail size.

Like all MRMS products, the use of multiple radars is more robust than single-site radar alone. It provides faster updates and helps the forecaster integrate data from multiple radars. It also compensates for cone-of-silence, beam broadening at far ranges, and terrain blockage.

Limitations

Training storms may mask overlapping tracks. In these cases, shorter duration accumulation times are recommended.

Subject to the biases and deficiencies of the mesoscale model used to derive the vertical temperature profile.

Quality Control

This product is derived from the 3D Reflectivity Cube, which means non-hydrometeorological data has been removed including: Ground clutter, anomalous propagation (AP), chaff, interference spikes, and bioscatterers (e.g., angels and ghosts). However, bright band contamination (i.e., anomalously-high reflectivity caused by melting snowflakes) remains.

Applications

Can be used to assess storm intensity trends and deviations in storm motion.

Useful to determine locations of the largest hail fall for NWS warning verification and emergency response.

Can be image combined with instantaneous MESH to create a MESH “Meteor Trails” bundle (Fig. 3) which is very useful for orientation of NWS WFO Severe Thunderstorm Warning polygons, CWSU Center Weather Advisories (CWAs), and other storm forecast track products.

Example Images

Fig. 1: Maximum Estimated Size of HA (MESH) products associated with a MCS over North Dakota and
Minnesota at 2300Z on 21 July 2014. Shown here are (a) instantaneous MESH, (b) 30-minute MESH
Tracks, (c) 120-minute MESH Tracks, and (d) 60-minute MESH Tracks.

Fig. 2: 120-minute Maximum Estimated Size of Hail (MESH) Track associated with a MCS over North
Dakota and Minnesota at 2200Z on 21 July 2014. The white lines are shown to illustrate how MESH
Tracks can be used to analyze the motion of the hail core.

Fig. 3: Image combination of instantaneous MESH and 60-minute MESH tracks (i.e., MESH “Meteor
Trails”) associated with a MCS over North Dakota and Minnesota at 2210Z on 21 July 2014.