Locally heavy storms will threaten outdoor plans and slow travel in portions of the northeastern US into Saturday.
"Some of the storms will be nasty with gusty winds and heavy rain," according to AccuWeather Chief Meteorologist Elliot Abrams.
People spending time outdoors or on the road will need to keep an eye out for rapidly changing weather conditions, especially during the afternoon and evening hours.
The downpours will occur as a storm pushes slowly eastward from the Upper Midwest.
One batch of showers and thunderstorms will press eastward from the Ohio Valley and central Great Lakes to the coastal Northeast into Friday night.
There is the potential for some communities to pick up a quick inch or two of rain in as many hours. This sort of rainfall can lead to street and highway flooding.
A small number of the storms can also be strong and gusty. Some tree limbs may break, which may cause a few sporadic power outages.
Flight delays will mount as storms approach then diminish after the storms pass and cloud ceilings rise.
A second batch of showers and thunderstorms will erupt on Saturday. However, these storms will likely form farther to the east, when compared to Friday evening.
As a result, much of the Midwest will be free of rain on Saturday, while many areas from the central Appalachians and eastern Great Lakes to the mid-Atlantic and New England coasts may get a second round of downpours.
There may be several hours of steady rain and rumbles of thunder from near the Chesapeake Bay to the Delaware Bay and southern New Jersey on Saturday afternoon and evening.
"Despite the overall unsettled weather pattern for the Northeast, most of the time in most areas will be free of rain," Abrams said.
"In the Northeast, Sunday looks like the best bet for outdoor plans," Abrams said.
Both days of the weekend will be free of rain for much of the Midwest.
Cooler-than-average weather for the middle of August will settle over much of the region next week.