The blizzard that walloped New York City in January is officially the biggest snowstorm in the history of the five boroughs, according to a new report prompted by questions about the accuracy of snowfall measurements.

Snowfall totals in Central Park were upped from 26.8 inches to 27.5 inches, making the Jan. 22-23 storm the biggest blizzard to hit the city since recordkeeping began in 1869, according to the National Oceanic and Atmospheric Administration.

"Snow measurements are extremely difficult to take because precipitation is inherently variable, a problem compounded by strong winds and compaction during a long duration event," National Weather Service Director Louis Uccellini, said in a statement. "Still, it's important that we scrutinize questionable measurements and reject those that scientists deem invalid to ensure the public's continued confidence in the U.S. climate record."

NOAA said the discrepancy in New York City stemmed from a miscommunication between the weather service's New York forecast office and the Central Park Conservancy, which correctly measured the snowfall.

The new record smashes the previous all-time mark of 26.9 inches set in February of 2006.

The change comes after a review of snow totals from the storm that clobbered the East Coast, dropping 40 inches of snow in some places.

The review also found that Newark Liberty International Airport's weather observers may have been improperly measuring snowfall totals since 1996 and likely inflated readings during January's storm to get an all-time record reading of 28.1 inches.

And widely reported suspicions about a 17.8-inch measurement at Reagan National Airport near Washington were unfounded. Although substantially lower than readings within the District of Columbia, the number was close to totals from nearby sites in northern Virginia, the agency said.

Weather observers are supposed to use 2-foot-square white boards checked every six hours. The team of contract observers at Newark Liberty took readings every hour.

"A separate team will investigate the best course of action to determine the accurate snowfall total and, as appropriate, amounts may be changed," the report said.

Observers in Newark have been retrained, NOAA said.