Holiday storm to spread drenching downpours from Plains to South

Santa will have to trade his snow gear for rain boots as a moisture-packed storm moves across the nation's midsection and South over the long Christmas weekend, bringing a threat of flooding downpours.

The storm, fresh on the heels of soaking Southern California and the Southwest deserts, will spread rain across most of the Plains and lower Mississippi Valley through Christmas Eve, while also delivering some snow to the Intermountain West and Rockies. By Christmas Day, the rain will expand across the Midwest and Southeast.

"After a relatively dry stretch of weather across much of the Plains and Southeast during the lead-up to the Christmas holiday, a change in the weather pattern will result in a soggy holiday for many," AccuWeather Senior Meteorologist Dan Pydynowski said.

Not only will the rain lead to a green Christmas, rather than a white Christmas, for this vast stretch of the country, but downpours can cause slow holiday travel, localized flooding as well as a few strong thunderstorms.

As the storm combines forces with moisture coming from the Gulf of Mexico, rain will break out from Texas northward along the Plains late in the day on Saturday and into Saturday night, say AccuWeather meteorologists. By Sunday, the rain will advance across much of the Upper Midwest, Mississippi Valley and even into the South.

The heaviest downpours, which can tally a couple of inches of rain as they move repeatedly over the same areas, will likely target the zone from the Texas Hill Country through the Arklatex Saturday afternoon and into Saturday night then closer to the Ozarks, Mississippi Valley and Gulf Coast come Sunday.

The repeated downpours can unload 1-3 inches in rain gauges, often in just a few hours, which can lead to flooding in cities such as Dallas, Houston, Little Rock and Memphis, as well as portions of interstates 10, 20, 30, 35, 40, 49 and 55. Some locally higher amounts near 4 inches are not out of the question.

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Embedded in the heavy rain can be a few thunderstorms, but a widespread outbreak of severe weather is not likely. Despite that, a few thunderstorms with strong wind gusts can't be ruled out along the Gulf coast, as well as back toward the main low-pressure system from the Texas and Oklahoma panhandles to the Ozarks, where hail could fall.

While the Plains and lower Mississippi Valley will begin to dry out by Christmas, millions more to the north and east from the lower Midwest through the Southeast will see the rain arrive for the holiday, including around Atlanta, Chicago, Jacksonville, Nashville and St. Louis. The threat of widespread flooding is low as the storm picks up speed, but it won't be a pretty picture for those who were hoping to spend time outside on Christmas.

"On Christmas Day, the storm will tap into copious amounts of moisture from the Gulf of Mexico," said Pydynowski, "This will bring a general inch or two of rain to cities such as Asheville and Greenville [South Carolina] into Monday night."

The wet weather will not end there, as the storm advances up the East Coast after Christmas.

"The storm can also produce difficult post-holiday road travel on Tuesday, Dec. 26, as rain spreads northward along the I-85 corridor, slowing travel from Charlotte to Raleigh and even into Virginia near Richmond," added Pydynowski.

Although many have dreams of a beautiful backdrop of snow outside on Christmas morning, the prospect of rain is not all bad. According to the latest U.S. Drought Monitor released last Thursday, a large swath of the area expected to receive heavy rain, from Texas to the Tennessee Valley, was in drought conditions, up to and including the most dire category, "exceptional" drought.

Since the beginning of the year, New Orleans has been nearly 25 inches below the historical average for rainfall, while Jackson, Mississippi, is about 15 inches below average. Since the beginning of June, many areas have received only 40 to 65 percent of the rain that is typically recorded over that stretch.

While the expected rain will not close those deficits entirely, any amount will provide some relief amid one of the worst droughts on record for the area, which is severely impacting regional economies.