After a warm and dry weekend across the mid-Atlantic states, a potent early week storm will generate drenching showers and thunderstorms, bringing a threat for flash flooding to many locations.
Potent low pressure will strengthen over the Ohio Valley on Monday, tapping into abundant moisture from the south, which will provide fuel for the drenching storms.
Heavy thunderstorms will first develop across much of the state of Ohio during the day on Monday, bringing torrential downpours to Columbus, Cleveland, Zanesville, and Youngstown.
By the time the evening commute rolls around on Monday, the heavy rain threat will transition into western Pennsylvania.
Many locations will pick up between 1 and 2 inches of rainfall with locally higher amounts possible. Rainfall to this magnitude will lead to flooding of streams and creeks.
In urban areas such as Pittsburgh, Columbus, Cleveland, and Erie, there is a risk of street and highway flooding, which can cause major delays for commuters traveling along Interstates 80, 76 and 79.
As the aforementioned storm shifts northeastward on Monday night into Tuesday, the threat for drenching thunderstorms will transition into central and eastern Pennsylvania as well as New Jersey and parts of New York.
One to two inches of rain will fall from State College, Pennsylvania to Philadelphia, Pennsylvania to New York City, New York, leading to an urban and small stream flood threat.
The evening commute on Tuesday will be very slow from New York City to Philadelphia. Some commuters may even face detours around any localized flooding problems that develop.
These drenching storms will slowly shift into central New England by Tuesday night as cooler and drier air filters into the mid-Atlantic states.
With many areas at or above their normal rainfall for the summer, flash flooding can occur rather quickly. Heavy rainfall will easily runoff into small streams, causing them to rise rapidly.
Small creeks can quickly turn into dangerous, fast-flowing bodies of water. Caution should be used when approaching these creeks as well as roadways that are covered with water.