What does the storm have to did with it? was it left outside?
you may have water in the spark plug tubes, there are 4, if so blow them out with compressed air.
otherwise it sounds as though it may be running to lean, and the colder weather it be more noticable. more popping out the exhuast on decel, and intake of popping on accel. in that case you would need to clean and or rejet the carbs.
did you gas up after the storm? water in the fuel?
but make sure you have mo water around the plugs before you go looking at fuel related issues