Tornadoes are forecast to swarm Friday through a very large and populated area of the nation, stretching from Illinois, Indiana and Ohio to Arkansas, Mississippi, Alabama and other states.

After a brief reprieve from severe weather today, a storm system emerging from the Rockies late this afternoon will act as the trigger for another round of dangerous storms in portions of recently hard-hit states and others late tonight through Friday.

Although residents in the Ohio and Tennessee valleys will have dry but breezy weather for clean-up efforts today, the tranquil weather will not last long.

Late tonight, storms are expected to erupt across eastern Arkansas, western Tennessee and northern Mississippi. Hail will be the greatest threat from this initial round of thunderstorms.

In light of less than perfect atmospheric conditions in the tornado and severe weather outbreak Tuesday night and Wednesday, it seems this potential event may have many key ingredients coming together.

Warm, moist air will combine with strong winds aloft in such a way to generate powerful thunderstorms that may spawn tornadoes.

The first storms are forecast to ignite near the Mississippi River late Friday morning into Friday afternoon and push eastward into the evening hours across the Ohio and Tennessee valley states.

Cities under the gun include Nashville, Tenn., Louisville, Ky., Cincinnati, Ohio, and Indianapolis, Ind.

In addition to the usual heavy rainfall and frequent lightning that accompanies thunderstorms, these storms could produce damaging winds, large hail and tornadoes.

AccuWeather.com meteorologists are concerned that Friday's severe weather outbreak has the potential to be more substantial than the one that blasted through similar areas Tuesday night and Wednesday.

The midweek outbreak was responsible for 12 deaths and 30 tornado reports.

The storms at the end of this week may be stronger and may cover a larger and more heavily populated area from the Midwest to the South, like some outbreaks from the past.

By Friday night, thunderstorms are expected to continue to whip eastward, rumbling through the Appalachians. If the storms remain intact, they could bring severe weather from Georgia through the Carolinas Saturday.

Stay tuned to AccuWeather.com through the end of the week as we continuously monitor and update this potentially significant severe weather outbreak.

From AccuWeather.com (find the original story here); reprinted with permission.