October 2018 Northeast Summary

For what is supposed to be the heart of fall, October presented quite a few twists and turns. For starters, summer continued to grapple with the region and even when the pattern finally flipped, rain seemed to persist every few days. Wintry weather was still on the back burner though, as only the interior parts of the Northeast received some of the white stuff. Let’s take a look at how the month panned out.

Early on, an upper level ridge provided unseasonable warmth and high humidity as temperatures still rose solidly into the 60s and 70s. A nearby boundary descended across New England on the 2nd, triggering a batch of severe thunderstorms on October 2nd which also resulted in several EF-0 and EF-1 tornadoes across Pennsylvania, New York and Connecticut! As the front meandered south, the next two weeks would feature high pressure that sent temperatures 10 to 20 degrees above normal.

Hurricane Michael would end up stealing the attention of the nation in the interim, becoming a powerful category 4, which made landfall on the 10th along the panhandle of Florida. The remnants of it were then pushed up the coast, dragging a deep and robust cold front into the eastern US between the 11th and 12th. In general, heavy rain impacted areas east of the I-95 corridor, generating 1 to 3 inches of rainfall between southeastern Maryland and northeast through southeastern Massachusetts. In another unusual round of tornadoes, several more EF-0s and EF-1s developed across southern Virginia, damaging several restaurants and mobile homes.

The front that pushed Michael into the Atlantic ushered in a regime change that finally brought seasonable weather into the Northeast and even much of the eastern seaboard. Temperatures fell about 5 to 10 degrees below normal at times by the third week, causing even some interior areas of the Northeast to experience abnormally cool nights with frost by morning. Otherwise, it was generally quiet with the occasional high pressure system straggling through. A series of cold fronts then brought some more rain, but nothing excessive like previous systems. They also helped reinforce colder air from the Midwest when even the Mid-Atlantic was not warming above 60 degrees.

A disturbance moved up from the south on the 26th into the 27th and combined with high pressure to our north to pool cooler air into New York and New England. It cooled just enough in the highest hills of the upper Hudson Valley, the Berkshires, and hills of Litchfield County in Connecticut for the first accumulating snowfall of the season. The rest of region experienced high wind gusts over 40 mph at times and a decent amount of rainfall, with 1 – 2” of rain in general. The northwest flow that followed triggered lake effect snow across New York, though most of the snow was still reserved for the higher elevations.

To round out the month, a quick low pressure system skirted across New England, which interestingly enough triggered an EF-1 tornado across Fisher’s Island in NY which caused quite a bit of damage to a few homes, and another waterspout that landed in Woods Hole, MA. Fortunately, this gave way to a pleasant Halloween with plenty of sun and mild temperatures well into the 50s and 60s.

Overall, the month was largely split in half between the continuation of summer and the eventual pattern shift that delivered us real fall. This essentially caused the month to be near normal in terms of temperatures, though the Mid-Atlantic states ended up 2 to 3 degrees warmer than usual. While it indeed felt quite wet and the grounds rather saturated at this point, most areas north and west of I-95 actually were below their precipitation normals (an inch or so at worst). The surplus of 2 to even 4 inches of rain along the coastal plain was mostly thanks to the remnants of Michael.