While some brief episodes of cool air are forecast, most days through the end of October will be much warmer than average over much of the eastern half of the nation.
“We foresee no sustained cooling over the eastern half of the nation for the next two weeks [from Monday, Oct. 9, 2017],” according to AccuWeather Lead Long-Range Meteorologist Paul Pastelok.
Temperatures from the South Central states to the Eastern part of the nation will average 10-15 degrees above average.
Shorts and short sleeves may be needed to stay comfortable during the day, but a jacket may be needed at night for some people.
The pattern will allow warm-weather projects, such as paving and painting operations, that were delayed this summer to continue.
Recent rainfall from Nate and non-tropical systems have put moisture back into the ground in many areas. This will reduce the spike in temperature during the afternoon hours, as some of the sun’s energy will be used to evaporate that moisture, rather than heat the ground and air in the lowest part of the atmosphere.
“Another factor against multiple days of extreme warmth will be cloud cover,” Pastelok said.
“Since the days are much shorter now, when compared to August or early September, a few hours of clouds or fog can really hold temperatures back.”
While temperatures may not be as extreme and persist as long as the peak of the heat in September, expect highs in the 70s to be common from Chicago to New York City. Highs are likely to be in the 80s on multiple days from Oklahoma City to Atlanta. There may be a day here and there where temperatures peak in the 80s and near 90 respectively.
At night, most people should be able to sleep without the air conditioner on. The lengthening nights during October will allow temperatures to slip back to 10 to 20 degrees lower than the previous day’s high.
A northward bulge in the jet stream is forecast to persist over the southeastern half of the nation most of the time through much of the balance of the month.
The jet stream is a high-speed river of air at the level where jets cruise at. South of the jet stream, temperatures are often warm. Up until nearly the end of the month, the jet stream will extend from the central Rockies to southeastern Canada.
While the jet stream will occasionally dip southward for a couple of days here and there, it is forecast to spend much more time in that northerly position rather than dip deep into the south.
The warm weather may delay or prolong the viewing opportunity for the fall foliage in some areas, at least where prior drought or gusty winds and rain from Nate have caused the leaves to fall off in the first place.
The same pattern responsible for the persistent warmth will keep the door open for tropical activity in the coming weeks.