A dangerous outbreak of severe thunderstorms is expected to begin Friday and last through the weekend in the Midwest, South and East.
NOAA’s Storm Prediction Center has issued a level 4 out of 5 risk of severe weather for both Friday and Saturday in portions of the Midwest and South, which means widespread severe storms are expected.
This threat level is uncommon, and is generally used only when supercells are capable of strong tornadoes, or long-lived squall lines are expected to produce widespread damaging winds. Take this threat seriously and know ahead of time where your safe shelter is and have multiple ways to receive warnings, especially since the severe storms could threaten at night in some locations.
Here’s a look at what to expect each day.
Friday-Friday Night Forecast
-Locations: Much of the Mississippi Valley as well as parts of the lower Ohio and Tennessee valleys are in the threat area highlighted by NOAA’s Storm Prediction Center above. Areas shaded red above have the highest risk of severe storms, including St. Louis, Paducah, Kentucky; Memphis, Tennessee; and Tupelo, Mississippi.
Zooming in even closer, the mid-Mississippi Valley is within the level 4 out of 5 threat of severe weather, which means widespread severe storms are expected in this region.
-Timing: This outbreak of severe storms likely won’t begin until later in the afternoon on the western edge of the forecast shown above. From there, the potential for severe storms will spread eastward through the evening and overnight hours toward the eastern side of the threat areas.
-Threats: Swaths of intense damaging wind gusts, tornadoes (possibly EF2 or stronger) and large hail could accompany any storms that turn severe. Tornadoes might spin up within a line of severe storms and with any supercells that develop.
Saturday-Saturday Night Forecast
-Locations: The Deep South has the highest risk for severe storms, including parts of Alabama, Georgia, Louisiana, Mississippi, Tennessee and the western Florida Panhandle. That includes Atlanta; Birmingham, Huntsville and Montgomery, Alabama; Chattanooga, Tennessee; Jackson, Mississippi; and New Orleans.
Zooming in closer, the level 4 out of 5 risk for widespread severe storms is from southeastern Louisiana to central and southern parts of Mississippi and Alabama.
Forecast guidance shows a potentially volatile setup that could produce dangerous supercell thunderstorms as well as one or more lines of severe storms in the South.
At least some severe weather could extend as far north as Ohio and western Pennsylvania.
-Timing: Thunderstorms, a few of which could be severe, might be ongoing in the morning from parts of the South northward to the Ohio Valley. The most intense severe weather will unfold in the afternoon and into the overnight hours, spreading from west to east across the threat areas shown above.
-Threats: Significant tornadoes (possibly EF2 or stronger), numerous damaging winds gusts and large hail are all concerns. In addition, flash flooding from heavy rain could impact northern parts of Alabama, Mississippi, Georgia, Tennessee and Kentucky.
(MORE: Nighttime Tornadoes Twice As Likely To Be Deadly)
Sunday’s Forecast
-Locations: The cold front might produce additional bouts of severe storms from the mid-Atlantic states to the Southeast as the weekend ends. That includes Charleston, South Carolina; Raleigh, North Carolina; Philadelphia; and Washington, D.C.
-Timing: Leftover storms from overnight, some possibly severe, will likely be ongoing in the morning in parts of the East. A combination of those storms possibly intensifying and new storms developing will keep the threat of severe weather going through the afternoon.
-Threats: Damaging wind gusts are the primary concern, but an isolated tornado is possible. Localized flash flooding could also occur in spots.
Classic Setup
The setup is familiar for March and the rest of spring, with a sharp southward plunge of the jet stream swinging out of the West toward the central and eastern states.
At the same time, the jet stream energy helps to form a strong low-pressure system along a cold front that draws increasing moisture north from the Gulf.
(MORE: Typical Ingredients For An Outbreak)
That combination of ingredients triggers the formation of numerous thunderstorms, some of which could rotate and produce tornadoes in addition to widespread damaging winds and hail.