One week after a wild stretch of winter weather slammed a large portion of the southern United States with snow, ice and bitterly cold air, some of the same areas are now facing the risk of flooding.
The same storm that brought some of the biggest snowfall accumulations of the winter to parts of Colorado on Wednesday and Thursday is expected to reorganize over the South Central states through the end of the week.
This system will be followed by a series of storms that are forecast to move along a developing temperature boundary.
As rainfall develops and lingers along an approximate 1,000-mile-long zone, flooding problems may escalate beyond urban areas to include rapid rises along small streams and high water along some rivers in the region.
Even though the snow and ice that occurred in the south-central region of the U.S. melted and ran off into streams and rivers prior to the arrival of the rain, the soil is still potentially wet enough for accelerating runoff as this rain event unfolds and evolves into a long-duration event.
An average of 1-4 inches of rain is forecast over a several-day period from central Texas to Maryland and Delaware, which would not be enough to trigger widespread small stream and river flooding.
"However, there is the potential for 4-8 inches of rain to occur in localized areas where downpours from multiple storms overlap into next week," AccuWeather Senior Meteorologist Brett Anderson said.
"An AccuWeather Local StormMax of 12 inches is foreseen within that 4- to 8-inch zone, and that big amount is probably most likely to occur over part of the Smoky Mountains in the southern Appalachians," said AccuWeather Senior Meteorologist John Feerick.
Prior to the start of this rain event, soil conditions ranged from average to abnormally dry to moderate drought west of the Appalachians, according to the U.S. Drought monitor. This means that the soil can handle a reasonable amount of rain over several days, which will be the case in most locations from northeastern Texas to eastern Tennessee and much of Alabama.
However, in areas such as Georgia, the Carolinas, Kentucky, West Virginia and Virginia, the soil is average to wet and cannot handle quite as much rainfall and more runoff is likely. Some of the rivers in the Carolinas were recently well above flood stage, a testament to the wet conditions from recent weeks.
Even though soil conditions are not as wet west of the Appalachians compared to locations farther east, localized small stream and river flooding will be a risk for the entire zone from the southern Plains to the western Appalachians during this stormy pattern.
"Exactly which locations in the zone end up with the worst problems is a tough call as the heaviest rainfall may fluctuate north and south, dissolve and redevelop as each storm moves along," AccuWeather Senior Meteorologist Bill Deger explained.
People who commute on secondary roads along small streams prone to flooding should expect some problems during the event. Likewise, people who live in flood-prone areas without the protection of levees should also closely monitor this evolving situation into next week.
In addition to the risk of flooding will be the potential for locally severe thunderstorms.
"The threat from severe thunderstorms may be primarily in the form of large hail rather than tornadoes," AccuWeather Senior Storm Warning Meteorologist Eddie Walker said.
During Thursday night to early Friday, this risk of thunderstorms with large hail about 1 to 2 inches in diameter is most likely from part of northeastern Texas to northern Louisiana, southern Arkansas and central Mississippi.
"Anytime there are storms with hail, the updrafts within the storm that allow the hail to grow in size can also produce strong gusts to reach the ground and potentially cause damage," Walker said.
As the storm systems move along the west-to-east temperature boundary, conditions may allow for additional thunderstorms with hail to develop and a tornado threat could evolve at some point into next week.
The air will turn warm and humid in the corridors of interstates 10 and 20 with temperatures forecast to climb well into the 70s F and even the 80s in some cases.
Sunshine can boost temperatures and make the atmosphere more unstable, which may then increase the intensity and coverage of thunderstorms. However, the presence of a deck of low clouds that limits daytime warming may deter severe weather. Both conditions are possible in different areas on different days south of the zone of persistent rain.
Factoring in the severe thunderstorm and rainfall potential at this time, the greatest risk to lives and property over a broad area in this situation is likely to be from flooding.
Another concern for motorists driving on stretches of interstates 20 and 40, and especially in the I-77, I-81 and I-85 corridors of the southern Appalachians and Piedmont, will be areas of fog once the rounds of rain commence. Fog can be especially dense over the ridges. Spotty ice and snow are also possible from portions of western Virginia, West Virginia and the mountains in western North Carolina with the leading edge of the rain early this weekend.