AccuWeather meteorologists are reporting that this fall is expected to be colder than normal, with blasts of winterlike air arriving early in the season.

As wild weather unfolds across the nation though, the tropics will also ramp up, putting the eastern coast of the United States at the highest risk for a direct impact.Polar vortex to returnWhile the fall will kick off with days of sunshine and temperatures above normal in some of the region's largest cities, including New York City and Philadelphia, the polar vortex may make its return for short, sporadic periods in September."The vortex could slip at times, maybe even briefly in September for the Northeast," AccuWeather Lead Long-Range Forecaster Paul Pastelok said. "There could be a significant shot of chilly air that comes across the Great Lakes region and into the interior Northeast sometime in mid- to late-September."As conditions in northern Canada begin to set up similar to last fall, getting colder and unsettled quickly, it is likely that this pattern could become a source for colder air to make its way down at times into the United States, inducing a drop in temperatures for the interior Northeast during mid-fall."Temperatures will not be as extreme in November when compared to last year, but October could be an extreme month," Pastelok said.After short-lived days of the polar vortex in September, the weather should turn a bit warmer in November as rain ramps up across areas from New York City to Boston and Portland, Maine, as well as the rest of the region."We will see some dry weather in the Northeast, barring any tropical systems, in September and October but in November it will get wet," Pastelok said.Following a soaking November for Northeastern residents, El Niño will make its debut early this winter, fueling early winter snow across the area."December could get kind of wild due to the very active southern jet stream that is going to provide the moisture for bigger snowstorms," Pastelok said. "The Northeast could have a couple of big storms in December and early January."Severe storms to unfoldWith the heart of hurricane season in the early fall, September is predicted to be an active month in the Atlantic."We are looking at a low number count for the tropics in the Atlantic, but we may have a couple more storms on the way," Pastelok said. "We've seen September in past years as an active month during past El Niño years, so don't count the season out yet."As the Southeast coast, from Florida up through North Carolina, is most susceptible for a direct impact from a tropical system this fall, areas farther north, including Boston and New York City, could experience rain from a tropical system as well."September is an active month and there could be some impacts, especially from Cape Hatteras, North Carolina, down through Daytona Beach, Florida," Pastelok said.Based on the weather patterns so far this summer, the lower Mississippi Valley and the Gulf Coast, specifically the central and western Gulf Coast, will be most vulnerable for a late severe weather season, according to Pastelok.Among the highest risks for autumn severe weather in late October and November are some of the Southeast's major metropolitan cities, including New Orleans, Jackson, Mississippi, and Little Rock, Arkansas."Some smaller risk in November may also be in the mid-Atlantic and parts of the lower Northeast, including Washington, D.C., Philadelphia and even New York City," Pastelok said.