Rose is surrounded by sunshine, but drawn to lightning storms, almost the opposite of misery loves company, like she's making a gamble on fighting those storms first hand. It probably makes sense. The Doctor is the Oncoming Storm, so Rose is the daylight after the storm. Maybe.

"'Ello!" she waggles her fingers in a wave with a bright cheery smile. "Lovely weather, innit?" Don't mind the London chav accent. "Do you want an umbrella or something?"