Weak echo region

From Glossary of Meteorology

weak echo region

(Abbreviated WER.) A region of weak radar echo that is bounded on one side and above by strong echo.

It is located on the low-altitude inflow side of the storm. The WER is produced by strong updraft that carries precipitation particles to midlevels in a convective storm before they grow to radar-detectable sizes. In identifying a WER with radar, care must be taken to ensure that the strong midlevel echo is related to an updraft and not to horizontal motion of precipitation particles (e.g., the spreading anvil).
See also bounded weak echo region (BWER).