Explain the possible purpose of the storm happening in "A Wrinkle in Time"?

First of
all, the storm sets the stage for "a dark and stormy night."Meg's life is stormy, and
as she, Calvin, and Charles Wallace face their adventures, they will battle darkness
itself.

The cause of the storm as a natural force is the meeting of heat and
cold.The temperature differences moves the air molecules in an erratic pattern, seemingly
senseless but with deadly purpose.This symbolizes the war between good and evil that will draw
in Meg and the others.The juxtaposition of the opposing forces (both in the storm and in the
battle) are the result of that clash.

L'Engle possibly could use the storm as
representative of the wholeness of the universe, both the physical and the spiritual.What occurs
in the spiritual world (good vs. evil) effects the physical world and the humans living in
it.The great cosmic battle overflows into the physical realm, setting off the atmospheric
disturbance.In chaos, evil excels.In the sequel "", L'Engle speaks of echthroi, evil
spiritual beings whose existence disturbs the natural world, as well as the spiritual psyche of
people.In the case of the storm, we can say that "the echthroi are
moving....."