What do you mean by "super cells"?

Concepts of atmospheric convection are evolving as measurement techniques (satellite and radar and automated precipitation intensity measurements) develop. In the formal terminology contained in the Meteorological Dictionary, PTE/IMGW 2003 the notion of a supercell and, even more, of a mesoscale convective system does not appear. There are no professors of synoptic meteorology in Poland, storm hunters simply transfer concepts from the USA to our local ground.
But remember that NY is at the latitude of Naples and the northern border of the USA is the southern edge of Poland. In addition, there are frequent inflows of air from the Gulf of Mexico, from disappearing tropical cyclones, with a significant water vapour content and thus enormous variability energy. The course of convection phenomena on the Great Plains has nothing in common with the course of convection over the Central European Lowlands; additionally, we lie in the shadow of the Alps, Sudetes and Carpathians.
We began to introduce the concept of the supercell in our commentaries published from 1998 onwards, when it became apparent that the numerical system was forecasting "peacock eyes" of rainfall in excess of 30 mm/3h every summer.
Going back to the definition - we consider a supercell to be an ensemble of multiple CB clouds, covered by a common anvil, with thunderstorms and heavy rainfall of course, but the ensemble does not produce its own circulation other than interacting in close proximity (20-30 km). A supercell is 80-200 km in diameter under central European conditions. A mesoscale convective system (in English MCS) produces its own longer-lived circulation in the form of a wave or a small low-level centre on a meridional front, or forms without a front in an air mass with significant variability energy and water vapour content.
From numerous satellite observations and sometimes from media reports, such MCS in and around Europe can be observed south of the Alps, the southern Carpathians and over the Mediterranean and Black Sea coasts; no typical MCS's are observed over Poland.