In "The Storm" as a whole, how do setting and plot reinforce each other?
Kate Chopin's short story "The Storm" depicts both a literal storm and a storm of passion between two lovers. As such, the plot and the setting, or the actual storm itself, definitely reflect one another.
When the story begins, Bobinot and Bibi are at a store expecting a rain storm to start any minute; meanwhile, Calixta, who is Bobinot's wife and Bibi's mother, is at the house. Calixta goes outside to bring in the clothes that were drying on the line and sees Alcee riding his horse; it is implied that the two had feelings for each other in the past, but Calixta "had not seen him very often since her marriage." Alcee asks if he can come sit on the porch until the storm passes, and she agrees. As the storm progresses, the tension between the two characters rises, as well. Alcee brings up a past rendezvous in Assumption. The narrator tells us,
for in Assumption he had kissed her and kissed and kissed her; until his senses would well nigh fail, and to save her he would resort to a desperate flight. If she was not an immaculate dove in those days, she was still inviolate; a passionate creature whose very defenselessness had made her defense, against which his honor forbade him to prevail. Now—well, now—her lips seemed in a manner free to be tasted, as well as her round, white throat and her whiter breasts.
Contrasting that moment in the past, it seems to Alcee now that Calixta will be more willing to answer his kisses; he turns out to be correct. After this, the narrator's description is very sensual. The characters don't even pay attention to the storm outside. Their passionate encounter is a storm in its own right. When the storm ends, order is restored. Alcee leaves. Bobinot and Bibi return, and normal family life resumes.
A bolt of lightning strikes a tree in Calixta's yard, and its "blinding glare and the crash seemed to invade the very boards [Calixta and Alcée] stood upon." It is this flash of white light that causes Calixta to stumble backwards, crying out, and it is this flash that seems to light them up as well. It is almost as though Calixta embodies the storm. Her eyes are described as a "liquid blue," like rainwater, and the glimpse of her "white neck" arouses Alcée "powerfully." She is like the lightning, her body gleaming and flaring, and
The generous abundance of her passion [...] was like a white flame which penetrated and found response in depths of his own sensuous nature that had never been reached. (emphasis mine)
Using a metaphor, a powerful figurative device, the narrator compares Calixta's passion to a "white flame," which sounds very much like the lightning that initiated their physical contact. Even her mouth is a "fountain of light," another comparison of Calixta to water. As they finish, "The growl of the thunder was distant and passing away." As their passion ebbs, so does the storm.
Alcée ends up writing to his wife that she can extend her visit to friends and family, and she is glad to receive his letter. "Devoted as she was to her husband, their intimate conjugal life was something which she was more than willing to forego for a while." Evidently, his love-making has something in common with a storm as well, and she is happy to escape it for a while. Thus, while other characters, including Calixta's husband and son, try to escape or hide from the storm, it seems that Calixta and Alcée figuratively embrace it when they embrace each other. They welcome the intensity that others try to avoid.
The setting is a tumultuous storm that comes in suddenly and takes over the small house, then disappears as quickly as it came, leaving a sunshine-filled day in its stead. This reinforces the plot because M'sieur Alcee also comes into the story like a storm, awakening stormy emotions and passions within Calixta, and their affair is a tumultuous and brief episode in her life, before things return back to normal. Afterwards, she is happy and carefree, laughing and kind, just like the cleared storm leaves sunshine in its path.
The bedroom is another element of setting that reinforces the plot; "The door stood open, and the room with its white, monumental bed, its closed shutters, looked dim and mysterious". Chopin's mentioning of the bedroom is not accidental, it is a foreshadowing of the coming affair, and, the mention of mystery alludes to the wondering of what being together would be like. That mystery is soon answered, and she becomes "a revelation in that dim, mysterious chamber". So, what was a mystery is now a revelation.
Those are a couple elements of setting that reinforce the plot.