The Miller Classification

December 4, 2020 // Article by: Mike Priante

No, we aren't talking about our very own meteorologist Brad Miller. The Miller classification is something meteorologists use to classify types of Nor'easters, named after the researcher J.E. Miller who came up with this system in 1946. Nor'easters can happen at almost any time of the year, but are most frequent and strongest between September and April. These are rapidly developing low pressure systems that form along the eastern seaboard and bring strong northeast winds (hence the name), heavy precipitation and coastal flooding. During the winter these storms can even produce significant accumulations of snow, sleet, and freezing rain, leading to millions of dollars in cleanup and millions of headaches. 

The first type of Nor'easter that we'll discuss is called the Miller A, or Type A. These systems typically originate off the eastern coast of Georgia or South Carolina, but can form as far south as the Gulf of Mexico. Miller A's then intensify as they move up the East Coast as a single storm before making a turn out to sea. They typically are quick movers, hitting the mid-Atlantic the hardest. However, New England can get significant snow depending on the intensity of the system. One example of a potent Miller A was the Boxing Day Blizzard of 2010, which brought over 2 feet of snow to places from Philly all the way to Boston. 

The second type of Nor'easter is called Miller B, or Type B. Their origin stories are a bit different, but their final destination is the same as the Miller A. A low pressure system first tracks over the Midwest, bringing a swath of rain, sleet and snow to parts of the Plains. This storm generally moves into the Kentucky/Ohio River Valley before it starts to transfer energy to a newly forming low pressure system along the coast of North Carolina and Virginia. From here, the newly redeveloped storm takes a northerly path before making a turn out to sea. Like its Miller A counterpart, Miller B storms bring a wide swath of snow and wintry weather with more inland areas of the mid-Atlantic and New England seeing the highest accumulations. A great notable Miller B would be the February 5th-6th "Snowmageddon" Blizzard of 2010, which brought over 2 feet to almost all of Maryland, including the D.C Metro. 

Although Miller A and B type systems aren't the only weather patterns that can bring snow to parts of the Northeast, they do typically produce the most snow and can impact a much wider area with different precipitation types, depending on the exact track. These systems are one of the most difficult to forecast far in advance, as they can be fairly complex and require the right ingredients to come into place at the right time. When those ingredients do come together though, you can almost guarantee that some area in the Northeast will see a full fledged winter storm.