Forecast Shows How Continuous Rain May Cause Flood Threats

AccuWeather meteorologists predict that a pair of weak storm systems will move from the Plains to sections of the Midwest and the eastern United States, bringing torrential downpours and violent thunderstorms. The second storm system will have the highest chance of hitting the mid-Atlantic coast.

(Photo : Photo by Joe Raedle/Getty Images)

Rising Concern

AccuWeather's forecast team was concerned about a rising possibility of flash flooding as the weather pattern developed. "Much of the region has been subjected to several rounds of strong thunderstorms resulting in torrential downpours," AccuWeather Chief Meteorologist Jonathan Porter said. "Localized flooding has already been an issue in several areas this week."

As severe thunderstorms and flash flooding continue to plague Montana and parts of the northern Plains this weekend, a major weather conflict zone will form hundreds of miles to the south and east from Friday through Saturday.

Also Read: Historic Yellowstone Flooding May Have Left Irreversible Damage to Montana

Storm Development

A small storm formed in the Colorado Rockies on Wednesday and dumped 2-4 inches of rain on parts of northern Kansas and Missouri and southern Nebraska and Iowa early Thursday morning. Cameron, Missouri, approximately northeast of Kansas City, Missouri, received 3.18 inches of rain in three hours.

This same storm system continued eastward over the Ohio Valley states into Thursday night, bringing heavy rain to the north and severe thunderstorms to the south.

Forecasters predict the risk of flash flooding will be greatest when this rain falls on top of earlier this week's storm. Even in areas where little or no rain has previously fallen, the downpours' strength can cause quick urban and minor stream flooding.

"There is a chance that this first storm system may weaken and fragment as it crosses the Appalachians before reaching the mid-Atlantic region on Friday," AccuWeather Senior Meteorologist Bill Deger said. On the other hand, a second storm system is expected to be more successful in bringing rain to the east.

The second storm will follow a similar course from the middle Plains to the Ohio Valley, with rain to the north and thunderstorms to the south predicted on Friday. On top of the rain that fell earlier this week, this will likely result in another 1-2 inches of rain, with locally greater amounts for certain regions.

Heavy Rainfall

The heaviest rain is expected to fall in a west-to-east belt stretching from central Illinois early Friday to northern and central Indiana and Ohio later Friday. This zone received 3-6 inches of rain earlier this week and is more prone to flooding than locations that did not get rain. From Peoria, Illinois, through Indianapolis and Columbus, Ohio, there is a potential for flash urban and small stream flooding.

On Friday, severe thunderstorms are possible from northern Illinois to central Kentucky and southern Ohio.

On Wednesday, heavy weather pounded a portion of this zone severely. According to PowerOutage.us, more than 10,000 people in Ohio were still without power as of Friday morning. According to the National Weather Service, one of the storms created an EF2 tornado in Goshen, Ohio.

More Rainfall

Significant rainfall is possible as the storm moves toward the central Appalachians and the mid-Atlantic from Friday night through the first half of Saturday. Washington, D.C., Baltimore, and Philadelphia are among the cities that might get a thorough soaking and disruptive downpours. Forecasters predict New York City will remain north of the heaviest rain, with only a handful of showers in store. Boston may not only be north of the showers but also struggle to receive any rain from the system.

"Drivers are urged to avoid regions where water covers the road since it is hard to determine how deep the water is or how rapidly the water is going," Porter warned of the impending danger. He went on to say that even six inches of fast-moving water can have disastrous consequences.

Storm's Trajectory

The storm should continue to move southward and out to sea in the mid-Atlantic area Saturday afternoon and evening.

Rain will be appreciated in portions of the Mid-Atlantic. There are pockets of extremely dry weather in southern Pennsylvania, Maryland, northern Virginia, Delaware, and southern New Jersey, but the drought is worst in southern Virginia and North Carolina.

In recent weeks, multiple storm systems and rounds of showers and thunderstorms have missed areas ranging from northern Pennsylvania and New Jersey to New England. With this time of year's bright sunshine capable of draining one-quarter to one-half of an inch of moisture from the ground daily, soil conditions have become exceedingly dry.

While this is excellent news for anyone with outdoor plans and building projects, AccuWeather Senior Meteorologist Dave Dombek believes that neither of the two storm systems will succeed in providing relief from the dry weather over upstate New York and northern New England.

"Instead, a reinforcing dose of chilly, dry air will surge southward this weekend over most of the Northeast," Dombek said.

Crop Planting

According to experts, July is a key time of year for maize, grapes, and various annual crops to fill out and develop for a healthy harvest to occur throughout the late summer and fall.

Dry air will sink southward after the second storm on Saturday night and Sunday. The deluge danger will be lifted in areas ranging from southern Pennsylvania to southern New Jersey to much of Virginia. Showers and thunderstorms are expected to continue in locations south of Virginia through the weekend and into next week.