Forecasters are predicting heavy rainfall this evening that could produce a flash flood threat, as well as a wet start to the weekend.

National Weather Service posted a hazardous weather outlook Thursday morning. According to the alert, "Periods of showers and thunderstorms with heavy rainfall are expected late today into Friday morning. This may bring a localized flash flood threat to the region."

AccuWeather reports as July draws to a close, a storm system swinging up from the Deep South will bring downpours to the northeastern U.S. and break the back of an extended heat wave.

Downpours will extend northeastward from the lower Mississippi Valley on Thursday into Thursday night. Locally gusty thunderstorms will erupt along with the drenching downpours from parts of Virginia to southern New Jersey during this time.

From Thursday night into Sunday, there is the potential for enough rain to ease abnormally dry and drought conditions.

Cloud cover and downpours associated with the storm system will cause high temperatures to trend from the 90s F to the 80s in most locations.

The storm will take a general path from the northwestern Gulf of Mexico coast to the Tennessee Valley, across the central Appalachians then off the New England coast.

"The exact track of the storm system will be a challenge to predict," according to AccuWeather Senior Meteorologist Brett Anderson.

At this time, the most likely locations for heavy rainfall will extend from parts of Kentucky to southern portions of Indiana and Ohio, much of West Virginia, northern and western Virginia, northern Maryland, central and southern Pennsylvania, Delaware, New Jersey, southeastern New York state and southern New England.

Within this swath, there is the potential for a general 1-2 inches of rain with localized amounts of 3-4 inches over the span of a few days. Despite the dry conditions in part of this swath, some locations could experience flash and urban flooding.

The core of the heaviest rain could shift farther north or south, depending on the track of the storm.

"This time of the year, the heaviest rain tends to fall near and south of the storm track, where the warmest and most humid air lies and where thunderstorms are likely to form and repeat," Anderson said.

The storm system has the potential to bring more rainfall than that which occurred on Monday in parts of the Northeast.

Because of the random nature of thunderstorms, some locations could still get missed by the big rain.

Later this weekend into early next week, in the wake of the storm system, humidity will lower significantly over the interior Northeast. In the mid-Atlantic, however, humidity levels will lower only slightly.

At least for a couple of days following the rainfall, the moist ground will tend to prevent extremely high temperatures during the daytime. The air at night may tend to remain muggy.

"Despite a little edge taken off the high temperatures by early next week, it will still feel steamy in much of the Northeast," according to AccuWeather Lead Long-Range Meteorologist Paul Pastelok.

Factoring in highs and lows, temperatures may continue to average slightly above normal in most locations during the first week of August.

"We expect another surge of heat and potentially a long-lasting heat wave in the Northeast around the second week of August," Pastelok said.