Long-tracking and intense thunderstorms have bombarded areas from the southern Plains to the Southeast this week with damaging winds, hail, tornadoes and torrential downpours. AccuWeather meteorologists warn that these same areas will remain at risk of strong thunderstorm complexes into next week before a change in the weather pattern occurs.
Through much of this week, complexes of thunderstorms have been developing and moving along the northern edge of a dome of heat centered on Texas then plunging southward toward parts of the Gulf and southern Atlantic coasts. As the pattern continued to ramp up, some long-tracking thunderstorms approached the official threshold meteorologists use to label such storm systems as derechos.
The official scientific criteria of a derecho, as described by the National Weather Service’s Storm Prediction Center, pertains to the swath of wind damage that must extend either continuously or intermittently for more than 400 miles with a width of at least 60 miles. But even where the storm complexes fail to officially become a derecho, they can still bring dangerous conditions and significant damage over a broad area.
At least two such complexes this week are candidates to be labeled a derecho. One began on Thursday afternoon in southwestern Kansas and the Oklahoma Panhandle and rolled toward northeastern Texas. A new complex of storms erupted in northeastern Louisiana Friday morning and continued to track southeastward across the lower Mississippi Valley during the daylight hours Friday. The combination of the two complexes has produced hundreds of severe weather reports ranging from high winds to large hail.
As the thunderstorm complex pushes toward the Florida Panhandle later Friday, more thunderstorms will erupt over portions of the southern and central Plains and Southeast states. However, the next major severe thunderstorm complex is likely to wait until Saturday afternoon to form over western and central portions of Kansas, Oklahoma and northern Texas, forecasters say.
Once these storms ignite on the rim of the heat later Saturday, a large complex will form and begin to roll swiftly toward the east and southeast across parts of the Ozark Mountains and on through the lower portion of the Mississippi Valley and Delta region during Saturday night.
On Sunday, the same complex or spinoff thunderstorm complexes will continue to roll over the south-central and southeast regions.
A few tornadoes are likely to be spawned along with the likelihood of multiple incidents of damaging winds and large hail.
Where the storms target the same areas within hours or a couple of days, the risk of flash flooding will increase substantially. Several inches of rain are likely to fall in some portions of the southern Plains, lower Mississippi Valley and the upper Gulf Coast.
Areas in the Southeast will likely pick up 6-12 inches of rain into early next week even as the derecho risk subsides. This is because there will be an ongoing potential for more thunderstorm activity – just not as organized or as fast-moving as the storms that will develop through this weekend.
“The threat for derechos or at least long-lasting severe thunderstorm complexes will decrease after Monday over the southern Plains,” AccuWeather Long-Range Meteorologist Brandon Buckingham said.
“The jet stream pattern will change its shape as to block much of the thunderstorms from slicing southeastward over a great distance from the southern Plains to the Southeast,” Buckingham said. “Instead, there will be more locally grown heavy to severe thunderstorms in the Southeast states, but conditions are likely to turn volatile farther north.”
AccuWeather’s long-range team of meteorologists anticipates an uptick in discrete severe thunderstorms – known as supercells – over the central and northern Plains from Tuesday to Friday of next week.
“These are the sort of powerful thunderstorms that can produce large tornadoes,” Buckingham said.
The same pattern will cause warmth to build substantially over the North Central states and into part of the Northeast. Since large wildfires continue in both western and eastern Canada, there is the potential for smoky conditions to expand and air quality to decline in the Midwest and the Northeast.
Produced in association with AccuWeather
Edited by Maham Javaid and Virginia Van Zandt