Destructive tornadoes, hazardous snowstorms and flooding rain have already accompanied the potent system along its cross-country trek.
Severe weather Wednesday sparked at least a dozen reports of tornadoes in Mississippi, while sirens blared overnight east of Birmingham, Ala. Several tornadoes touched down into early Thursday morning. One twister in Shelby County, Ala., lofted debris high enough that it appeared as a “tornado debris signature” on radar.
One person was killed Wednesday night as a likely tornado plowed through Marengo County, Ala., about midway between Meridian, Miss., and Montgomery, Ala. Damage was also reported from a possible tornado that struck near Spartanburg, S.C. Thursday morning and from tornadoes in the vicinity of Charlotte, N.C.
Torrential rain from the storms in the Southeast has led to many areas of flooding, including flash flood emergencies in parts of western South Carolina and southwest Virginia, the most severe type of flood alerts.
Meanwhile, heavy snowfall on the storm’s cold side set records in western Texas. After not receiving snow in more than four years, Midland wound up with 7.9 inches: the city’s ninth-largest snowfall on record, dating back to 1933.
In other parts of the Lone Star State, the storm brought wintry weather rarely seen: A mixture of sleet and other ice pellets was even reported Wednesday night by a National Weather Service employee near Corpus Christi, on the southern Texas Gulf Coast.
More severe weather, heavy rain and snow are on the way for many near and east of the Appalachians.
Overnight, storms refused to weaken. That means Thursday began with a head start, with strong to severe thunderstorms rolling across Dixie Alley from Alabama into Georgia.
More broadly, the National Weather Service Storm Prediction Center has outlined an enhanced risk of severe weather from the Florida Panhandle through much of Georgia and eventually encapsulating the eastern two thirds of the Carolinas.
Strong southerly winds about a mile above ground associated with the low-level jet stream will provide the necessary wind dynamics to encourage storms to rotate. Tornado watches stretched from the Florida panhandle through extreme southern Virginia midday Thursday.
A line of strong to severe thunderstorms was advancing along the cold front midday Thursday, producing widespread gusty to locally damaging winds and triggering several tornado warnings in the Carolinas, including around the Charlotte area.
Storms will make it to the Interstate 95 corridor by Thursday evening before weakening and exiting offshore during the overnight.
The same low-level jet stream fueling severe storms will act as a conveyor belt, scooping up moisture from the deep tropics and helping slingshot some semblance of an “atmospheric river” north ahead of a cold front. The front will serve as a focusing mechanism, tapping into the humidity to produce a slow-moving line of downpours. Imagine blasting a fire hose at a brick wall: All the water from that moisture stream collects in the same area.
The entirety of northwest Georgia was blanketed beneath flash flood warnings early Thursday, and these warnings were expanded into central Georgia as well the western Carolinas and southwest Virginia by the afternoon.
Storm total rainfall of two to four inches is likely, with a few spots ending up with half a foot when all is said and done. The heaviest rain will last up to eight hours in any one location; the highest amounts will be found where storms “train” and move over the same areas repeatedly.
Flood watches stretch a thousand miles from the Gulf Coast to near New York City. On the order of three inches through very early Friday is likely in the Carolinas, while one to two inches are expected around the District of Columbia and Baltimore.
Ponding of water on the roadways is possible in the southeast and Mid-Atlantic on Thursday afternoon and evening, adding an unwanted hiccup to the evening commute.
A wallop of winter
An inch or two of snow is possible in Chicago on Thursday as colder air meets a bit of leftover moisture. A similar feature may lead to a broad, light snowfall over parts of Missouri, Indiana and Ohio.
The system is now working up the East Coast and will soon meet significantly colder air. A gentle covering of snow occurred in Boston before transitioning to rain Thursday morning, while areas away from the coastal plain well inland saw a bit of icing and/or snow.
Winter storm warnings are up well to the north in extreme northeastern New York, northern Vermont and New Hampshire, and western Maine. A few spots could see up to 18 inches of snow by Friday night.
Where does the storm go next?
Once finished lashing the eastern United States, the storm will exit to the north and east toward Canada, all the while dragging its atmospheric river with it. That will produce up to a foot of snow in Newfoundland across the northern Avalon peninsula.
Thereafter, the atmospheric river could ride the jet stream east and bring heavy snow to Britain late this weekend into early next week.