An active pattern featuring multiple rounds of disruptive thunderstorms from the Ohio Valley to the Eastern Seaboard is on tap for the early part of this week, forecasters say.
The potentially severe weather is likely from Monday to Tuesday evening as energy surges eastward ahead of a broad zone of low pressure.
"As yet another potent piece of energy pushes eastward from the Midwest toward the Northeast to start the workweek, severe thunderstorms are expected to follow an advancing cold front," said AccuWeather Meteorologist La Troy Thornton.
"On Monday, dangerous storms are expected from far northern Tennessee across Ohio and much of Pennsylvania, extending southward through to the North Carolina coast," he said.
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Numerous cities from the Ohio Valley to the mid-Atlantic coast will be at risk for severe weather from Monday to Monday evening, including Indianapolis, Louisville, Ky., Nashville, Columbus, Ohio, Pittsburgh, Charleston, W.V., Baltimore and Philadelphia.
On Monday, roughly 65 million residents will be within the zone for strong to severe thunderstorms.
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The strongest storms on Monday will bring the threat of isolated tornadoes and damaging wind gusts ranging from 60-70 mph. The AccuWeather Local StormMax is set at 80 mph for the thunderstorms that develop on Monday.
"Monday should present a higher tornado threat as opposed to Tuesday because of stronger turning of the winds with height or shear," explained Thornton. "This phenomenon allows for the columns of rising air that build thunderstorms, called updrafts, to rotate, and this rotation can lead to tornadoes if it can be maximized and sustained."
Another primary concern with any storms that develop from Monday to Monday evening will be torrential downpours that elevate the risk of flooding. Portions of the Ohio Valley have already faced impactful rainfall in recent days, raising the water table and hiking up the danger of additional flooding.
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Locations such as Nashville have already received roughly 75% of their typical August rainfall, with additional rain expected to spread across the region through Monday night as storms develop.
As this feature becomes much more organized as it tracks into the Eastern states, forecasters say that a few elements will play a role in the storm's potential impacts across the region.
"The setup supporting these storms will include a wide variety of factors," stated Thornton. "First, a robust influx of moisture into the region from the Gulf of Mexico will occur due to southwesterly winds ahead of the cold front."
Thornton added that thunderstorms should be able to tap into the energy provided on both days by strong winds just above the surface, with any storm that does so being very likely to produce severe-caliber wind gusts.
Moisture will surge from southern Ohio toward the Pennsylvania-Maryland border by the evening hours on Monday. Some locations are likely to observe dew points exceeding the 70-degree mark by the end of the day, which can feel rather sticky for this section of the country.
The storm and associated frontal boundaries will advance to the East Coast on Tuesday, spreading intense bursts of rain and thunderstorms from southern Mississippi to far southeastern Pennsylvania and southern New Jersey.
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Travelers along portions of interstates 10, 75 and 95 are advised to closely monitor the progression of the storms on Tuesday, given that the intense downpours could induce slowdowns and periods of decreased visibility.
Additionally, any beachgoers from New Jersey to the Georgia coast could deal with disruptions to their outdoor activities as thunderstorms develop and track to the coast. Storms are likely to unfold across a heavily-populated corridor, to begin with, and given the time of year, vacationers that have flocked to the coast could increase the number of people that can face storms on Tuesday.
A corridor across far northeastern South Carolina to far southeastern Virginia could face a moderate risk for severe storms, and even a risk for isolated tornadoes.
Forecasters say that Wednesday may turn out to be a much nicer day than the start of the week across a large portion of the Eastern U.S.
"As the cold front clears the Northeast coast later Tuesday night, calmer conditions can be expected on Wednesday," Thornton said. "However, thunderstorms may linger around the coast of the Carolinas and into the Southeast as the front hangs up a bit longer over those areas."
Temperatures are likely to moderate by midweek across the eastern half of the nation, dropping between 5 and 10 degrees at the start of the week in some spots.
As a storm system tracks eastward across southeastern Canada, there will be additional chances for rainfall by the latter half of the week, particularly from the Great Lakes to the Northeast.
