Severe weather will threaten a large area into Monday night, stretching from the Northeast, through the Midwest and into the Plains.
Thunderstorms that develop in this area will be the product of two separate systems; a cold front swinging into the Northeast and a wave of low pressure following quickly in its footsteps.
Pittsburgh, Cleveland, Cincinnati, Pittsburgh, St. Louis, Omaha, Nebraska, and Des Moines, Iowa, are a few cities that could be impacted by Monday's storms.
According to AccuWeather Chief Meteorologist Elliot Abrams, "The storms targeting areas from the Ohio Valley to upstate New York and part of northern New England will bring an elevated risk of damaging wind gusts."
Hail and localized flash flooding will also occur in some of the storms.
The storms into Monday night will generally stop short of the I-95 corridor.
In the Midwest, Detroit and Chicago will also avoid the worst of the storms.
The St. Louis area could be hit by two rounds of storms: One during Monday afternoon and another late Monday night.
Areas from southeastern South Dakota to the central portions of Missouri and Illinois will also be in the path of severe thunderstorms.
Folks in this large area over the Central states should prepare for the worst as thunderstorms can bring flooding downpours, large hail, damaging wind gusts and even a few tornadoes.
It is important to know the difference between a tornado watch and a tornado warning if you plan on being in the area impacted by Monday's severe storms.
Remember that a tornado watch means that the conditions for tornado development are present, while a tornado warning means that a tornado has been detected.
If you are under a tornado warning, you should seek shelter until the warning has been lifted.
On Tuesday, severe thunderstorms will once again threaten an area from western New York, through the Ohio Valley and into southern Missouri.
Similar to Monday's storms, thunderstorms on Tuesday could lead to urban flooding, hail as large as golf balls, wind strong enough to blow over trees and power lines, and even a few tornadoes.
This will put cities such as Pittsburgh and Cincinnati in the path of severe thunderstorms for a second day in a row.
Some of the severe storms will reach the northern and western suburbs of the I-95 major cities Tuesday evening, before weakening.
Fortunately, the severe threat is expected to diminish heading into the middle of the week as the system weakens.
Showers and thunderstorms will still be present across the Northeast on Wednesday, however, threatening outdoor activities from Boston, through New York City and into Washington, D.C.
AccuWeather Senior Meteorologist Alex Sosnowski contributed content to this story.
Tropical Storm Matthew has formed in the Caribbean could take a turn toward the United States as a hurricane next week.
It will feel like an extended winter for those living from the northern Plains to the eastern U.S., as cold and snowy conditions last longer than normal.
The final day of September will bring a rare lunar event that hasn’t occurred since March of 2014, a Black Moon.
Rain will spread over much of the northeastern U.S. into the weekend, but persistent downpours will raise the flood risk in part of the mid-Atlantic.
A new typhoon is brewing in the western Pacific Ocean and could pose a risk to Japan, Taiwan and eastern China next week.
Thundery showers set to start this weekend will depart before the season's first National Football League game in London kicks off on Sunday.
Snow in New England and Pennsylvania mountains.
Terre Bone Parish, LA (1915)
Hurricane hit with 140-mph winds. The storm wrecked 90 percent of the buildings in town. Central pressure of 951.9 mb; 275 killed, $13 million damage.
St. Louis, MO (1927)
Tornado 300 feet across with a 4-mile path crossed river. Twister killed 72, caused $22 million damage. Total of 81 dead from outbreak and $25 million damage.