Snowfall blanketed the nation’s capital on Monday, causing traffic disruptions and transforming the city’s iconic monuments into picturesque wintry scenes. Residents may be puzzled as to why this winter storm did not extend its wrath up the coast to cities like New York and Boston, unleashing heavy snowfall and powerful winds. The reason lies in the broader atmospheric conditions governing the storm’s trajectory, a phenomenon described by National Weather Service meteorologist Zack Taylor as not entirely uncommon.
The prevailing weather pattern at play is known as “zonal,” denoting the west-to-east movement of weather systems across the country. This particular storm exemplified this zonal flow, depositing snow and ice in a swath spanning approximately 1,100 miles from the central Plains through the Ohio Valley to the Mid-Atlantic region throughout Sunday and Monday. Concurrently, a significant storm in Atlantic Canada exerted its influence on the weather in the United States, redirecting storm activity southward away from the mid-Atlantic region, as highlighted by AccuWeather meteorologist Tom Kines in remarks to USA TODAY.
The expansive 1,100-mile path of the storm showcased a snow accumulation exceeding 6 inches, a remarkable event as observed by meteorologist Jonathan Erdman. This display of zonal flow contrasts with a meridional flow, where upper-level winds intersect latitude lines at sharp angles, typically associated with slower-moving and intensifying storm systems, such as nor’easters. These powerful storms, marked by intense low-pressure systems developing off the East Coast during late fall, winter, and early spring, are notorious for their impact on cities like Boston, New York City, Philadelphia, and Washington, D.C. Nor’easters bring with them robust northeast winds, heavy precipitation, and coastal inundation, often culminating in blizzard conditions in New England.
However, the snowstorm that blanketed Washington, D.C., on Monday does not meet the criteria for a classic nor’easter, as clarified by Taylor. Nor’easters are characterized by their expansive reach and potent effects, particularly along the densely populated East Coast. Instead, the recent storm’s trajectory and intensity were governed by the zonal flow pattern, which facilitated its swift west-to-east movement.
As meteorologist Jeff Haby elucidated, the distinction between zonal and meridional flow lies in the alignment of upper-level winds relative to latitude lines. Zonal flow, with winds running parallel or near parallel to latitude lines, often propels storms swiftly from west to east. In contrast, meridional flow, where winds intersect latitude lines at acute angles, fosters the formation of slower-moving, intensifying storm systems conducive to significant weather events.
While the impact of the recent storm was felt keenly in the nation’s capital, other major cities along the East Coast were spared the brunt of its force due to the interplay of atmospheric conditions. Understanding these nuances of weather patterns and their influence on storm behavior provides valuable insight into the dynamic and occasionally unpredictable nature
