As rain and thunderstorms streak from the Midwest to the Northeast into Thursday, the stage will be set for some of the thunderstorms to turn severe each afternoon and evening.
"It appears that the states of Ohio, Pennsylvania, West Virginia and Maryland will have the highest risk for damaging thunderstorms and even a tornado," according to AccuWeather Senior Meteorologist Brett Anderson.
Akron and Youngstown, Ohio; Pittsburgh, Harrisburg, Philadelphia and Allentown, Pennsylvania; and Hagerstown, Maryland, are among the cities facing severe weather daily into Thursday.
A tornado watch has been issued by the National Weather Service for much of Pennsylvania that will be in effect until 10 p.m. EDT. More than 14 million people live in the area where the tornado watch has been issued.
The first severe storms erupted over western Pennsylvania around 2:30 p.m. EDT Tuesday with one storm hammering the town of Stoneboro with hail nearly as large as tennis balls, according to trained spotters in the area. Large hail was also reported in Kittanning and Selinsgrove, Pennsylvania.
At 5:02 p.m. EDT Tuesday, there was a radar-confirmed tornado near Rome, Pennsylvania. It is unclear if this storm has caused any damage or injuries.
The threat zone into Tuesday evening will also encompass Fort Wayne, Indiana; Cleveland, Ohio; New York City; Trenton, New Jersey; and Baltimore.
A heavy, gusty thunderstorm may graze Dayton, the site of Monday night's devastating tornado, before the severe weather risk increases on Wednesday.
The threat on Wednesday afternoon and evening will also shift southward to Columbus, and Morgantown, West Virginia and remain across Baltimore.
Many of the same areas being threatened on Wednesday will face another round of violent thunderstorms on Thursday afternoon and evening.
"The thunderstorms will move quickly, which reduces the risk of flooding," Anderson said, "however, thunderstorms may move over the same areas during an extended period of time (training storms), which increases the risk for urban and flash flooding."
The ground is already saturated following what has become a wet May in many areas.
"These thunderstorm complexes may also produce thousands of cloud-to-ground lightning strikes as they race eastward through the region," Anderson said. "Residents should be prepared for power outages due to the lightning and powerful straight-line wind gusts."
There can also be incidents of hail pounding more communities.
The stormy weather pattern will continue to plague farmers, construction crews and sporting events. Baseball games in Philadelphia, Baltimore, Pittsburgh and New York City can be subject to delays and/or postponements into Thursday.
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The severe weather into Thursday will ignite as a significant temperature contrast sets up across the eastern United States.
"Parts of the Ohio Valley and mid-Atlantic will be stuck in the battle zone between extreme heat in the Southeast and cool, maritime air in the Northeast," according to Anderson.
Temperatures will once again soar into the 90s across the southern mid-Atlantic, including Richmond, Virginia, and Washington, D.C., on Wednesday and Thursday. Humidity will create even higher AccuWeather RealFeel® Temperatures.
On the other hand, temperatures will be stuck in the upper 50s and lower 60s these days in Portland, Maine, and Boston.
Much better weather is anticipated for anyone with outdoor plans on Friday.
"Drier air will sweep into the region later Thursday night and Friday, ending the risk for severe thunderstorms," Anderson said.
While more showers and thunderstorms may return this weekend, there are signs that next week may be drier with less frequent bouts of showers and thunderstorms.
EDITOR’S NOTE: Kristina Pydynowski is an AccuWeather senior meteorologist.