A deepening low pressure system associated with a strong, closed-off 500mb low moved from the central Gulf Coast to central PA Sunday and Sunday night, taking an unusual track across the spine of the Appalachians. This placed Northwest Pennsylvania in the area of snowfall on the northwest side of the storm Sunday evening into Monday with snow only slowly departing the Snowbelt on Monday as lake enhancement contributed to continued heavy snowfall there well into the day.
The combination of the storm's size, track, intensity, and amount of moisture led to a heavy snow event for all of Northwest Pennsylvania. This area was sandwiched between warmer and more humid mid-level air drawn up east of the storm and colder, drier air being pulled in from the west. This tightening temperature gradient aloft (known as frontogenesis), along with the region being on the nose of a very strong easterly flow aloft, drawing in unusual amounts of moisture drawn from the Atlantic, and an atmosphere that was less stable than usual contributed to banded, very heavy snowfall across much of Northwest Pennsylvania for several hours late Sunday evening through early Monday morning. Snowfall rates of 1 to 2 inches per hour were common in this banded snow, and continued in the deformation snow that was enhanced by Lake Erie in the Snowbelt into Monday afternoon. These prolonged heavy rates made roads nearly impassable in many areas come Monday morning. The snow was initially wet Sunday evening, with some brief mixed precipitation occurring in parts of interior Northwest Pennsylvania. The snow became higher ratio, lighter snow into Monday morning, with winds turning gusty into Monday and causing blowing and drifting. Where lake enhanced snow continued well into Monday in the Snowbelt, totals of over 2 feet occurred.
Impacts from this event were significant for the Martin Luther King Jr. holiday. While schools and several businesses were closed for the holiday, many businesses scheduled to be open during the holiday either remained closed or were delayed opening. Roads across the region were impassable for hours due to heavy snow. Many accidents occurred with stranded vehicles remaining across area highways for days. The highest snowfall total from this event in Northwest Pennsylvania was 25 inches in Erie. Other selected totals across the area include: 23.9 inches in Millcreek Township, 23 inches in Summit Township, 22.7 inches in Greene Township, 22 inches in Greenfield Township, 21.9 inches in Cherry Hill, 20 inches in Girard and Spring Township, 19.8 inches in Harborcreek, 18.9 inches in Meadville, 18.8 inches in Lake City, 18 inches in Corry, 17.8 inches in Springboro, 17.5 inches in Edinboro, 16.7 inches in Cochranton, 16.2 inches at Erie International Airport, 16.1 inches in North East Township, 15.9 inches in Conneaut Lake, 14.5 inches in Atlantic, 13.5 inches in Union City, 10.7 inches in Titusville, and 10.5 inches northwest of Jamestown.