News•February 11, 2013

Rich Moisture Feed Helped Blizzard Bury Northeast

The weekend blizzard in the Northeast, dubbed “Nemo” by The Weather Channel, socked the region with stunning snowfall totals of more than 3 feet in some places. A persistent band of extremely heavy snow, with snowfall rates in excess of 4 inches per hour, sat over parts of Connecticut and Massachusetts for several hours during the height of the storm, resulting in the snow jackpot of 40 inches in Hamden, Conn.

The amazing snowfall totals were, in part, the result of the rich tropical moisture feed that the storm tapped into, as Climate Central reported on Feb. 8. Data from the University of Wisconsin's Cooperative Institute for Meteorological Satellite Studies, showed the amount of total precipitable water over New England was more than 200 percent of normal for the region at this time of year.

The storm produced the heaviest snowfall on record in Portland, Maine (31.9 inches), the fifth-largest single-storm total in Boston (24.9 inches), second-heaviest snowfall on record in Hartford (22.3 inches), and the second-heaviest snowstorm of all-time in Concord, N.H., with 24 inches.

University of Wisconsin animation shows total precipitable water values as high as 1.9 inches being drawn northward into the intensifying low.

A second animation from the University of Wisconsin shows the total precipitable water values were in excess of 200 percent of normal for this region and this time of year.

Climate studies have shown that as the world has warmed, the atmosphere is carrying, on average, more moisture that can be wrung out by storms as rain or snow. In the Northeast, during the cold season in recent years, big 24-hour precipitation events such as a blizzard have accounted for an increasing proportion of the seasonal precipitation total. This indicates that extreme-precipitation events are playing a larger role in the cold season, and these events, including this blizzard, can have major societal impacts.

Studies have linked this trend in extreme-precipitation events to manmade global warming. However, much of the increase in one-day, extreme-precipitation events during the cold season in the Northeast has taken place in the fall and early spring, rather than February.