Traditionally Storm subconsciously psionically altered atmosphere variables (temperature, pressure, humidity), which is what I always assumed was meant by meteorological patterns, in order to consciously elicit meteorological phenomena. The explanation of her lightning is that she can excite electrons in atmospheric molecules.
Storm still shouldn't have sufficient control over electromagnetic force to create an electromagnetic pulse instantaneously whereas someone like Magneto would. She still shouldn't have sufficient control over even electrical fields to consciously shut down a person's cardiovascular and nervous systems from afar. Has she constantly and consistently done either of these things? Or are these more singular events.