A line of severe storms is expected to slam the Northeast after a week of pleasant temperatures and sunshine across portions of the region.

Starting Thursday, a severe storm threat will plague the Northeast, bringing heavy rain and thunderstorms.

A Level 2 out of 5 severe weather risk is in place from New York City to Pittsburgh, but the exact timing of the storms remains uncertain.

This threat extends over 1,000 miles from northern Tennessee through western Maine. 

“Showers and thunderstorms lingering into Wednesday night could leave behind cloud cover and rain-cooled air, limiting instability across parts of the Ohio Valley and Mid-Atlantic,” the FOX Forecast Center said.

Despite this, forecasters predict there to be enough moisture and instability to surge to the north by midday Thursday.

A thunderstorm passes over the skyline of lower Manhattan and One World Trade Center in New York City on May 20, 2026, as seen from Hoboken, New Jersey. Getty Images

The moisture, which is driven by an unusually powerful jet stream and a fast-moving cold front, will advance from the western US, triggering widespread thunderstorms.

According to the FOX Forecast Center, cooling air will allow for discrete storms capable of producing large and damaging hail.

Locations facing the greatest risk of these storms on Thursday include Washington, D.C., New York City and Philadelphia.

Scattered severe thunderstorms are possible from parts of New England to the mid-Atlantic and Appalachians. The main threat is damaging wind gusts, but some hail and locally flooding rain is also possible. The Weather Channel Severe thunderstorm risk in Massachusetts from Thursday, June 18, at 8 a.m., to Friday, June 19, at 8 a.m., per the National Weather Service. USA TODAY Network via Reuters Connect

As the persistent heavy rainfall continues, it will fuel a Level 2 out of 4 flash flood risk across portions of the Ohio Valley, West Virginia and Western Pennsylvania.

Forecasters note that along with this powerful area of low pressure, a tight wind gradient will set up over Lake Erie and Ontario, producing wind gusts of up to 55 mph along the shores.

As a result, wind alerts have been issued across the interior Northeast as a powerful area of low pressure approaches.

Flooding is possible through the evening hours, along with the coastal threat.