The National Oceanic and Atmospheric Administration report, released Wednesday, said the weather service's biggest problem was communicating storm surge predictions more rapidly to state officials.
Storm surge, which is the abnormal rise of water being pushed toward the shore by the force of the winds, reached historic levels on parts of Long Island during Sandy. The surge combined with the tide to create flooding that plagued residents for days after the storm.
NOAA's assessment team interviewed emergency management officials from Sandy-affected regions, including those in Nassau County and New York City, said Peyton Robertson, director of NOAA's Chesapeake Bay office and team leader for the Sandy assessment.
"The emergency managers there indicated while they got storm surge info, there were things they didn't fully anticipate -- for instance, in Nassau County there were waves on top of the surge," which exacerbated the flooding, Robertson said.
He noted emergency officials preferred a graphic display of predicted surges. "Everyone wants the map; 'Can you show it to us in terms of a geographic info system,' " he said the emergency officials asked him.
Another recommendation was to give predictions as early as possible, Robertson said. "Even though going further out means less certainty, the OEM [Office of Emergency Management] officials said they would rather have more lead time. They want the worst-case scenario."
Suffolk County Executive Steve Bellone said through a spokeswoman that the NWS was slow to provide crucial storm surge information during Sandy.
"The NWS provided Suffolk County a forecast for the storm surge, but much later than they should have -- that information was just not coming to us in a timely matter. But given the fact that we plan for a higher event than what is predicted, it gave us the safety margin for the surge that arrived," Bellone spokeswoman Vanessa Baird-Streeter wrote in an email. "We also had a representative from the NWS in our emergency operations center before and during the storm who provided us the information as soon as he received it, which was a major help to us."
But a spokesman for Nassau Executive Edward Mangano said the NWS forecasts helped with the county's planning. "Having a National Weather Service forecaster at the county executive's side was a valuable asset in assessing and enacting parts of Nassau's plan," spokesman Brian Nevin wrote in an email. "Clearly, the National Weather Service was an important partner in preparing for Hurricane Sandy and provided important information with respect to forecasting and storm surge predictions."