Strengths

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.

The use of mesoscale model analysis data to derive temperature information allows the temperature fields to vary across the domain of interest. This is in stark contrast to applying a single temperature altitude proxy across the entire domain, as is often done for single radar calculations. Thus, MRMS data better captures gradients in the temperature fields over space and time.

Limitations

Like many of the other hail size estimation techniques, which use reflectivity and vertical temperature profile input, MESH has a tendency to underestimate hail size in:

• Highly-tilted storms embedded in strong, deep-layer shear.
• Left-moving supercells.
• Supercells which possess a giant Bounded Weak Echo Region (BWER). This is sometimes denoted by a low MESH value hole co-located with the BWER.
• Storms with low-density, dry hailstones.

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 remains.

Applications

MESH has been shown to be very useful for assessing both the 2D distribution of hail and largest hailstone size associated with a storm.

Example Images

Fig. 1: Maximum Estimated Size of Hail (MESH) for a short-lived severe thunderstorm (within white
circle) over North Dakota on 21 July 2014 at 2108Z. MESH is approximately 2 inches, near a SPC storm
report of 1.75 inch hail.