April 5th-6th, 2022 Severe Weather

On April 5th, the most significant severe weather event in 2 years struck the NWS Columbia CWA, and was a widespread tornado outbreak across the southeast. In all, it brought 8 tornadoes to our CWA and 66 tornadoes overall across the southeast. This included 13 strong tornadoes (EF2+ in strength). The first storms to impact our area came out of Allendale County, which repeatedly produced supercells through the evening. This group of supercells produced 5 of our 8 tornadoes. As the evening progressed, a QLCS (a line of storms) pushed through the region and produced three different tornadoes before finally giving the region a break. That was followed up by a lesser, but still impactful, event on April 6th.

Severe weather began to be a distinct possibility up to a week in advance. Forecast models began showing a shortwave trough passing through the region on April 5th during the afternoon and evening hours up to 5-6 days in advance of the event. The fact that the models continued to hone in on an afternoon timing was important, as that is our most favorable time for instability and shear to combine.

SPC forecasts began to highlight our area in a Slight Risk (or equivalent) on April 2nd, highlighting wind damage and a few tornadoes as the primary threat. SPC gradually ramped up the threat as we approached the event (this matched up well with model guidance), eventually placing the southern half of the Midlands & CSRA in an Enhanced Risk. This matched up with long-range Machine Learning Probabilities from Colorado State, a new tool we're using in our office this year.

By Saturday, some of the models began to trend a bit southward with the forecast low and features. But leading up to the event on Sunday and Monday, the high-resolution guidance quickly shifted in the other direction. It is never a good thing when models quickly ramp up as you approach the event, and this really happened. They began to show a good combination of high-end shear, more than adequate moisture, and sufficient instability, especially along and south of I-20. Moreso, some hi-res guidance was really beginning to show some discrete storms developing ahead of the main line, which would pose a more significant tornado threat.

Put all of this together and you have a concerning setup leading into the event. We had nearly all hands on deck at the office ready for whatever the next day would bring.

The event itself took its origins over Louisiana and Mississippi early on April 5th. A shortwave trough emerged out of the ArkLaTex region, and forced a surface low to push through northern MS and Alabama and eventually into western NC. This shortwave helped to force an area of rain that initially pushed through the region during the late morning and early afternoon hours, and helped to keep things fairly stable at least initially.

The real environment took shape quickly after this first area of rain began pushing northward.

The aforementioned shortwave pushed quickly from the ArkLaTex region through the TN River Valley, forcing a surface low to pass to our north. This was critical in setting up our environment, as plentiful moisture and wind shear developed, especially along and south of I-20.

The environment quickly became primed after the initial bout of rain push through. Instability quickly advected into the region, and this was one of the primary uncertainties leading up to the event. With shortwave forcing and high-end wind shear, only 500 j/kg or more of MLCAPE was necessary. It certainly helped that much of that was contained in the lower levels of the atmosphere, favoring tornadoes if supercells could get going.

Overall, we issued 15 tornado warnings that day, in addition to 11 severe thunderstorm warnings with the main QLCS itself.

A summary of this tornado is in the above map, but this was quite the powerful tornado. It produced intense tree damage near the beginning of its path, and thankfully weakened before it moved into populated areas.

A brief but strong tornado with winds up to 115 mph developed over the city of Manning towards the end of the event. This tornado formed within the QLCS portion of the event, and was the last tornado of the day.

Another tornado produced by the QLCS, this tornado was on the ground over a mostly rural area and did a lot of tree damage. Winds are estimated to have been as high as 135 mph with this tornado.

The severe weather didn't stop on April 5th. On April 6th, cold air in the mid-levels of the atmosphere pushed eastward across the Carolinas and Georgia, creating substantial instability.

Wind shear was significantly weaker on April 6th when compared to April 5th, and storms really behaved like organized pulse storms. They would pulse up and down occasionally, primarily producing heavy rain. The strongest storms produced wind damage across our western counties.

The severe weather probably wasn't the most impactful portion of this event, though. Multiple rounds of heavy rainfall impacted Lincoln County, GA, McCormick County, SC, and Edgefield County, SC. Over the course of a few hours on April 6th, 4-6" of rain fell in parts of those counties. This led to significant flash flooding, including multiple roads being washed out in Lincoln County.

It was an active couple of days to start the month. Thankfully, no fatalities or serious injuries were reported in our Forecast Area from either the tornadoes or the flash flooding. We'd like to thank our partners in Aiken, Bamberg, Clarendon, Lexington, and Orangeburg Counties for their aid in surveying the tornado damage from April 5th!