More than 35 million people in the Central states and 25 million along the Atlantic coast will be at risk for severe weather later this week.
The air will become warm enough ahead of a late-week storm over the Missouri and Mississippi valleys, as well as parts of the East to bring not only thunderstorms, but also the potential for severe weather, damage and flight delays.
The main threats of the storms will be locally powerful wind gusts and flash flooding. A number of locations may also experience hail with the storms. A small number of the storms could also produce a tornado.
According to Severe Weather Expert Henry Margusity, "The greatest risk for a handful of tornadoes will be where the air is the warmest and most humid, which is most likely from western Tennessee to northwestern Mississippi on Thursday."
The potential for damaging thunderstorms by Thursday will stretch from Louisiana, Mississippi and Alabama to Illinois, Indiana and Ohio, as well as the southern part of the Lower Peninsula of Michigan.
Cities on Thursday that could be impacted by gusty strong to severe thunderstorms include St. Louis and Kansas City, Mo.; Indianapolis; Cincinnati; Nashville and Memphis, Tenn.; Little Rock, Ark.; Louisville, Ky.; Jackson, Miss.; and Monroe, La.
While snow on the ground will limit the intensity of some of the storms, it will not eliminate the risk of severe weather everywhere.
Even in the absence of thunderstorms, locally strong wind gusts can affect areas from the Midwest to upstate New York on Thursday into Thursday night.
On Friday, the potential for strong to severe storms will reach from northern Florida to Pennsylvania, New Jersey and southern New York state.
However, during Friday, the storms along the Atlantic coast are likely to be much less widespread than from the day before farther west.
According to Senior Meteorologist Ken Clark, "We will probably have a narrow line of gusty thunderstorms pushing east of the Appalachians and toward the Atlantic beaches."
During Thursday and Friday, some storms will hit where there is still snow on the ground. In part of this area, there may not be much thunder and lightning. There can be still a brief gust of strong wind that can down tree limbs and power lines, as well as cause minor property damage.
The combination of a surge of warm air and rainfall will raise the risk of ice jam flooding on some streams and rivers from the lower Midwest to the mid-Atlantic.
The weight of recent snowfall and the added rain coming with the storm could be enough to stress some roofs to the point of failure.
Melting snow ahead of and during the passage of a cold front associated with the storm can lead to street and poor drainage area flooding, where storm drains have become blocked with snow.
The risk of flooding downpours and gusty thunderstorms will increase across southern Florida as a tropical disturbance shifts northwestward from Cuba this weekend.
Slow-moving and repetitive downpours will raise the risk for flash flooding along the western Gulf Coast into early next week.
Typhoon Lionrock is poised to make landfall in Japan early in the new week with heavy rainfall, damaging winds and an inundating storm surge.
Hawaii is facing two tropical threats next week as Madeline and Lester churn westward.
Hot and dry weather will greet fans and competitors at the 2016 U.S. Open Tennis Championships in Flushing, New York, as play begins Monday, Aug. 29.
President Obama visited flood victims in Louisiana this week, while several tropical systems were on the prowl in the Atlantic.
Cedoux, Saskatchewan (1973)
Largest hailstone ever recorded in Canada. This stone was 4.5 inches in diameter and weighed a pound.
The Bronx, NY (1990)
Strong thunderstorms dumped 4.24 inches of rain.
Nassau, NY (1990)
Thunderstorm winds overturned boat, injuring 12.