Essentially, the jet stream assumed a position much further north than normal for the early winter months. This allowed warm air (from the south) to flood into our area, while the coldest air was capped well to the north. As areas of Low pressure passed through the Great Lakes, we ended up being on the mild side of those storms, resulting in rain instead of snow. Another factor that impacted our unseasonably warm weather was the weak to mild El Niño occurring off the coast of South America (which often has a significant impact on weather globally).
Allentown, PA 18102