President's Day Snow Storm
It was the "Presidents Day Blizzard" for New York City and Boston and a record breaking, crippling snow storm for Washington D.C., Baltimore, MD, and Philadelphia, PA. When compared to the amount of snow and overall impact the storm had in the big east coast cities to what happened in the Capital Region, you could accurately say that a glancing blow was delivered to this region. However, that "Glancing" blow still brought upwards of a foot of new snow in the immediate Capital Region with anywhere from 14"-20" in the eastern Catskills, mid Hudson valley and Berkshire and Litchfield counties. Interestingly enough, the actual surface storm that aided in the production of the snow was weak and rather poorly defined. So in this case the Northeast corridor was pummeled by a major, and in many places a record breaking snowfall, with the absence of a major coastal storm.
Wind gusts in excess of 40 mph in New York and Boston created the necessary blowing snow and reduced visibility criteria for at least three hours to classify the system a blizzard in those cities, although true blizzard conditions were relatively short in duration. 27.5" of snow fell on Boston, the most from any storm, 20" on New York City for the the city's 4th all time heaviest snow, and in the neighborhood of 20"-24" fell on Washington, Baltimore and Philadelphia setting snowfall records and crippling those cities for days. Up to 50" of snow fell in the mountains of eastern West Virginia and western Maryland with a mixture of snow sleet and freezing rain further south in Virginia and North Carolina.
The true driving force behind the exceptionally heavy snowfall was an enormously strong area of arctic high pressure that moved across southern Canada and northern New England during the weekend preceding the heavy snow in the Capital Region, rather than low pressure which is typically the culprit in big east coast snow events. The high pressure system brought some of the winter's coldest air to eastern New York and western New England on the 15th and 16th, with a record setting low daytime high temperature at Albany on the 16th of only four degrees.
The combined effects of the clockwise circulation around the high pressure system, and the broad counterclockwise circulation around the rather weak and disorganized low pressure system forming in the southern branch of the jet stream over the southeast U.S. created a favorable warm air inflow pattern over, initially the Midwest, during the weekend. As warm moist air from the south circulated around the developing southern low it climbed up and over the shallow layer of arctic air, forced south from Canada around the high pressure system. The circulation and lift pattern that resulted allowed snow to develop in a narrow zone from Iowa and Illinois Friday afternoon. That snow then spread east through the Ohio valley and mid Atlantic through the weekend. The slow motion of the main weather players allowed a non stop conveyor belt of warmth and moisture to overrun the surface layer of cold air to produce a very long duration steady moderate to heavy snow that inundated the Midwest, Ohio Valley, and mid Atlantic through Sunday, the 16th. Aiding in the copious snow production was a subtropical moisture tap that the evolving disturbance in the southern branch of the jet was able to establish sending moisture rich air over the very cold air in place from the Northeast through the mid Atlantic. The result of course were the crippling snows for the region.
The high pressure system was able to hold precipitation out of the Northeast through the weekend, but by President's day, the 17th, the high moved east. The resultant change in position allowed weak low pressure to form along the coast allowing the conveyor belt of overrunning air to move north into New York City, the Capital Region, and New England through the morning of the 17th. Snow began in the immediate Capital Region around 10:00am and continued through midnight and even a few hours into the early morning on the 18th. The coldness of the air over the region created a very steep surface for the warm moist air to ride over, creating rapid vertical motions in the atmosphere that allowed snowfall rates to increase to close to two inches per hour at times in areas just south and east of Albany, through New York, and eventually to Boston. Several jet stream features also moved north in concert with the overrunning pattern to enhance the snowfall in eastern New York and western New England.
Since much of the driving force behind the production of the snow was the circulation around the arctic high pressure system to the Northeast of the region and the weak coastal low pressure system, terrain played a significant role in the snowfall distribution across parts of Rensselaer, Washington, and Bennington counties. Strong east winds just above a layer of shallow NNE winds near the ground interacted with the mountains in Washington and Rensselaer counties as well as those surrounding Bennington, VT. The net result was for the mountain effect to cause the air flow to sink into places like Bennington, VT, Salem and Hoosick Falls, New York. As the air came down off the mountains, (downsloped) it compressed and dried, greatly reducing the amount of snow that fell in those communities. In fact, only about 3" of snow was reported in Bennington, VT, Hoosick Falls, NY, and only about 5" in Salem in southern Washington county. Just outside of the snow shadow zone, snowfall amounts jumped to between nine and fourteen inches. Snow amounts then dropped off sharply from Fulton county on north into the Adirondacks, farther from the best lift in the atmosphere, with amounts ranging from as little as three inches in Hamilton county to up to nine inches in Fulton county. 11.9" of snow fell on Albany on the 17th, which broke a 24 hour snowfall record for the date of 10.4" set in a storm in 1952. Another inch fell on the 18th for a grand total of 12.9" at Albany adding to the tremendous snow pack already on the ground from the Christmas day, 2002 storm, and the January 3-4 storm.
Observed Snowfall Distribution Map For the February 17th, President's Day, 2003 Storm
(This graphic was created using snowfall data collected by WRGB's exclusive WeatherNet 6 weather spotter network)
WeatherNet 6 Town By Town Snowfall Totals For the February 17, 2003 Snow Storm