That's not what the national polls said. Romney was leading by a point in the RCP average, quite consistently, until the storm hit. After the storm hit, Romney was down by a point in the RCP average of the national polls. He saw a 3 point negative swing in Pew and WaPo polls.
You are correct. There are millions of low information voters that don't tune into the presidential election race until a week before you vote. They get their information from the major TV networks.
Guess what they got to see on TV for the week before the election? Republican governor licking the boots of the little boy president.