Days after Typhoon Neoguri takes a curved path over Japan and into the northern Pacific, much cooler air will drive southeastward across the Midwest and into the Northeast.
The cause and effect of a typhoon curving away from Asia is well known among the weather community.
“A southward dip in the jet stream over Asia is what is turning the typhoon out to the east,” according to AccuWeather Senior Meteorologist Joe Lundberg.
The jet stream is a fast river of air, high in the atmosphere, that guides storms along and allows fair weather systems to build over a particular region.
“If you think of the jet stream as a really long jump rope and start to shake one end up and down, eventually those waves will show up at the other end of the rope,” Lundberg said.
However, the shape of the jet stream is constantly changing.
The dip in the jet stream over eastern Asia now will show up over part of the central and eastern United States approximately six to 10 days later.
“The dip in the jet stream could lead to temperatures averaging 5 to 10 degrees F below normal,” Lundberg said.
The greatest temperature departures from average will be over the Upper Midwest to the central and northern Appalachians. The cool air will lose some of its punch along the I-95 corridor.
During a two- to three-day stretch, we are potentially looking at highs in the 70s around the Great Lakes and the low to mid-80s in the I-95 corridor. The effect of strong sunshine may negate the coolness by day. However, where it stays cloudy during the day, temperatures may be significantly lower than currently forecast.
“The most noticeable impact may be at night, when temperatures could dip into the 50s in Midwest cities, near 60 F in the I-95 mid-Atlantic and the 40s in the central and northern Appalachians,” Lundberg said.
There have been multiple waves of cool air this spring and summer over the Midwest and Northeast, but it is likely that this will occur during what is typically the hottest part of the year. This may make this particular episode more impressionable.
The cooler air is likely to reach its peak in the Midwest Monday to Wednesday and then in the East Wednesday into Friday.
“Some cooler and less humid air can even reach into part of the South for a time next week,” Lundberg said.
After a shallow push of cooler and less humid air, not associated with the typhoon, runs its course later this week, a warmup will occur ahead of the big push of cool air next week.
The warmup will occur this weekend into early next week but could be strewn with clouds, showers and thunderstorms.
“As the big push of cool air begins, one or more waves of severe weather may be possible during the first part of next week,” Lundberg said.
More at AccuWeather: Typhoon Neoguri to Usher Cooler Air Into East for Mid-July