WASHINGTON – Before the first snow fell, U.S. meteorologists realized there was a good chance the late-winter storm wasn't going to produce giant snow totals in big Northeast cities as predicted.
But they didn't change their forecasts because they said they didn't want to confuse the public.
National Weather Service meteorologists in Boston, New York, Philadelphia and Washington held a conference call Monday afternoon about computer models that dramatically cut predicted snow amounts. They decided to keep the super snowy warnings.
"Out of extreme caution we decided to stick with higher amounts," Greg Carbin, chief of forecast operations at the Weather Prediction Center in suburban Maryland, told The Associated Press. "I actually think in the overall scheme that the actions (by states and cities) taken in advance of the event were exceptional."
On Monday, the weather service predicted 18 to 24 inches of snow in New York City. By late Tuesday afternoon, Central Park was covered with a little more than 7 inches of snow with rain and sleet still falling. Other areas, including upstate New York and Connecticut, received more than a foot and a half of snow. Swaths of Pennsylvania were walloped by 20 to 30 inches of snow.
Carbin said a last-minute change downgrading snowfall totals might have given people the wrong message that the storm was no longer a threat. It still was, but real danger was from ice and sleet in places like New York City and Washington, he said.
Dramatically changing forecasts in what meteorologists call "the windshield wiper effect" only hurts the public, said Bob Henson, a meteorologist for the private Weather Underground.
Carbin stood by the decision.
"The nature of the beast is that there's always uncertainty in every forecast and we have to get better at describing that," Carbin said.
The right amount of precipitation fell, but it came down as rain and sleet because the rain-snow line moved inland, according to Carbin and private forecasters.
The rain-snow line is a 50 mile wide north-south swath where cold Arctic air from the north and west clashes with warm, moist air from the Atlantic. West of the snow line saw heavy snow while east had rain and sleet.
The snow line happens to center on New York City so it was a bigger deal than if the line had been over a rural area, said private meteorologist Ryan Maue of WeatherBell Analytics.
Private forecast outfits said the National Weather Service did a good job forecasting a tough storm despite the beating the federal agency took on social media.
"Overall the range of the forecast was very solid. It ended up being on the low end," Henson said. "I understand why people can be frustrated when the expectation is the big storm."
University of Georgia meteorology professor Marshall Shepherd, host of the television show "Weather Geeks," said the public focused too much on worst-case scenarios.
"The perception of `bust' is that it didn't materialize for New York in the manner expected. Much of the expected snow fell as sleet," Shepherd said in an email. "To me, ice is a far greater hazard. If a pitcher throws a strike down the center of the plate or just off the outside corner, it's still a strike."