By Charlotte Huffman

PHILADELPHIA (CBS) – “I think for big storms, the National Weather Service has been 90 plus percent right,” said Mayor Michael Nutter during a press conference Tuesday morning.

But this go around, the National Weather Service got it wrong, and the meteorologist in charge, Gary Szatkowski, isn’t afraid to admit it.

“Weather forecasting is not perfect but this was a miss by a pretty wide margin,” he said.

He says computer models provided conflicting guidance and the area in which the storm developed made a small change that had big implications.

“It developed further off shore than what we thought. Again, we are only talking 75 to 100 miles and that made all the difference in the world…It wasn’t until around midnight last night that it became not quite crystal clear, but pretty clear that we weren’t going to see the snow like what we’d forecasted in Philadelphia and parts of Jersey.”

By then, decisions to declare a state of emergency in New Jersey and a snow emergency in Philadelphia had already been made by government officials.

Just before one o’clock Tuesday morning, Szatkowski tweeted the following apology:

“You made a lot of tough decisions expecting us to get it right, and we didn’t. Once again, I’m sorry,” his tweet said.

“I think when someone steps up that way we should acknowledge their honesty,” Mayor Nutter said during a Tuesday morning press conference.

“We realize people depend on the forecast. We’re going to do everything we can to make the forecast as accurate as possible. Obviously we’re not yet there where we can be accurate 100 percent of the time, but we’ll keep striving to be the best and to improve,” said Szatkowski.