An upcoming change in the weather pattern that AccuWeather meteorologists have been forecasting for the past several weeks is about to unfold. As the pattern change takes shape, a storm could provide opportunities for some rain in the coming days and weeks in portions of the parched Midwest and Northeast.
A large southward dip in the jet stream has been funneling cool air and smoke from Canada into the mid-Atlantic and Great Lakes regions this week. The same pattern has kept Gulf of Mexico and Atlantic moisture well away, with the exception of parts of New England where rain from the Atlantic has been a frequent visitor.
Starting this weekend, the jet stream will shift as a storm forms over the central Plains. While this storm may not initially grab a tremendous amount of moisture from the Gulf, it will produce its own moisture due to rising air.
“Spotty thunderstorms that have been riddling the Plains much of this week will consolidate into a zone of rain and thunderstorms from Missouri to Michigan this weekend,” AccuWeather Senior Meteorologist Brett Anderson said. “It will not rain steadily for very long in this zone, but some locations will get a thorough soaking.”
“Even though drought conditions have been long-term and much worse across the High Plains to the west, a lack of drenching rain in recent weeks has caused soil conditions to dry out rapidly over the Midwest and into portions of the Northeast,” Anderson said.
For example, rainfall has only been about 30% of the historical average in the zone from St. Louis to Chicago since May 1. There have only been a few drops of rain in the zone from Columbus, Ohio, to Detroit and Pittsburgh, since May 20. And since 0.25 to 0.50 of an inch of water can evaporate on a daily basis, the topsoil has become very dry. The combination of breezy conditions and dry air at times has also pushed the wildfire danger to levels rarely seen at this point of the season.
“The dry winds have been kicking up a considerable amount of dust on recently plowed fields, so any soaking rain would be of great benefit,” Anderson said.
Most of the downpours from Missouri to Michigan are likely to occur from Sunday afternoon to Sunday night,” Anderson said.
“Farther to the east, in portions of the Ohio Valley, the central Appalachians, the eastern Great Lakes and the mid-Atlantic, which have been dealing with the brunt of the smoke from wildfires in Canada, the rain will likely wait until Monday and Monday night.”
AccuWeather meteorologists believe that an average of 0.50 of an inch of rain is likely from the storm in the Midwest, with some places potentially picking up 1-2 inches of rain where downpours persist and last for a half a day or more. Still, a few spots may miss out on the heaviest rain and only receive 0.25 of an inch or less.
“As the storm tracks eastward, it will have a better chance to tap into that Atlantic and Gulf moisture, which should enhance rainfall from the Middle Atlantic region through the Appalachians and eastern Great Lakes,” Anderson said. These areas stand a better chance of picking up closer to an inch of rain or more from the storm early next week.
Parts of the Northeast are coming off an extremely dry May – one of the driest on record in many spots – and little to no rain has fallen since June began. Many locations have been experiencing a rapid escalation from dry to drought conditions.
Rain is often accompanied by the chance of thunderstorms in the summertime, and that will be the case with this storm system as well.
“Locally heavy to severe thunderstorms may accompany the rain potential from Sunday afternoon to Sunday evening in the zone from Missouri to Michigan,” Anderson said.
On Monday afternoon and evening, the severe thunderstorm potential is likely to extend from parts of Ohio, southeastward to Virginia and northward to upstate New York and across the Canadian border into southern Ontario, Anderson added.
The greatest risk from the thunderstorms is likely to be from powerful wind gusts and hail, although downpours may be heavy enough to cause brief episodes of flooding on streets and highways.
This storm will pave the way for more rain opportunities, or at least better chances of showers and thunderstorms in the Midwest and the East, AccuWeather’s Lead Long-Range Meteorologist Paul Pastelok said.
“Another storm is likely to follow later next week, but the path that storm takes will determine the northward distribution of rain,” Pastelok said. A more northern track would allow a greater amount of showers and thunderstorms through much of the Midwest and Northeast, while a more southern track may limit most of the showers primarily to areas from the Ohio Valley to the Southeast.
“Should the storm take a more northerly track, it could send some rain into areas in southeastern Canada toward the middle of the month where forest fires are raging and outputting huge amounts of smoke into the U.S.,” Pastelok said.
The same second storm system next week may bring a marked uptick in severe thunderstorms over portions of the middle and lower Mississippi Valley and central and southern Plains.
The storm bringing rain from Sunday to early next week won’t just bring drought relief – it will also improve the air quality across parts of the East.
“As this storm takes shape Sunday into Monday, the steering winds, which have been directing the smoke plumes southward from Quebec, will shift and will begin to force the smoke back into eastern Canada,” Anderson said. However, the same steering winds may direct more smoke toward the northern Great Lakes, a region that has largely avoided similar air quality issues thus far.
Produced in association with AccuWeather