Fall Freeze

October was a tale of two half-months. Summer-like weather prevailed through the 11th, quickly transitioning to fall-like conditions on the 12th. Passage of the first strong cold front of the season was responsible for the change. Moderate to heavy rain accompanied the front in northwest NJ during the daytime hours of the 11th. That evening, and into the morning of the 12th, moisture from the remnants of once major Hurricane Michael ran up against the front and brought heavy rain to south Jersey. This one-two punch was followed on the 17th by the first freezing temperatures of the season at a few locations and a more widespread freeze on the 19th. Generally cool conditions prevailed the remainder of the month. The remnants of yet another major hurricane, Willa, provided energy and moisture to a quick-hitting nor’easter on the morning of the 27th that brought some of the worst coastal flooding since Sandy in 2012. Michael was an Atlantic storm that made landfall in the Florida panhandle, while Willa was an eastern Pacific storm that came ashore on the west coast of Mexico.

There were many sides to New Jersey’s October 2015 weather, however, when temperature and rainfall observations were averaged, conditions were quite close to long-term (1981–2010) means. The statewide average temperature of 54.4° was 0.4° below normal. This ranked as the 53rd coolest since 1895 (121 years). Precipitation averaged 4.17", which is 0.24" above normal and ranks as 44th wettest. October was bookended by events that dumped the vast majority of the month’s precipitation, with an extended period of very dry weather in between. This led to a continuation of moderate drought in the northeast, with nearby areas remaining abnormally dry. The late-month rain, which for the first time in many months was heaviest over the driest areas, staved off the need for any further drought deterioration, at least for the time being. The major weather event of the month extended over the first five days, when incessant onshore winds generated the worst beach erosion and back bay flooding since Sandy three years ago, though not nearly in the same ballpark of what Sandy wrought.