Nothing but the plot, words, and punctuation are mine.

I want it to rain September first. It'll be a Wednesday, and Elliot's children's third day of school. They can stop by on their way home, waddling into the precinct with umbrellas, raincoats, and yellow plastic boots, like drenched ducks. They can sit in Cragen's office. He'll let them sit on his desk and swing their feet off it. It will make him smile—something he hasn't done in a while. They can hang their rain coats on the coat post by the stairs, and I'll make them hot cocoa. Their yellow boots can be walking up the stairs, one on each tread. It would confuse Huang. They could leave their umbrellas hanging off our desks.
I want it to rain September first. Alex will come home that day—back home, back to the roost, where I can play mother hen to her again. She will come out of hiding that day, I know it. And it will rain. We can stand in the rain together on the roof of the precinct, all seven of us, just standing in the rain, faces to the clouds. No rain gear necessary. Our hair will get sopping wet, although Cragen won't have to worry. Fin will let out his ponytail, and it'll be longer than Alex's, but slightly curly. We'll get soaked.
I want it to rain September first. It won't need to be symbolical. I don't need symbolism. Not even Munch will need any theories that day. We can just sit around our desks, the seven of us and Elliot's children, and look out the huge glass windows of the squad room, watching the rain. Then I'll stop aching for it. We can sit around and sip hot cocoa. We can be safe inside.
I want it to rain September first.
Is that too much to ask?