The Mid-South remains under the threat of the most significant severe weather event since the Super Tuesday tornado outbreak.
As of 1pm, little has changed with respect to the potential for severe weather over the next 24 hours or so, other than a slight increase in the confidence factor as models start to latch onto a more unified solution. The Storm Prediction Center has placed the metro region under a Moderate Risk of severe weather for both this afternoon/tonight and tomorrow and has just issued Tornado Watch #80 until 8pm, which includes metropolitan Memphis.
The first round of severe thunderstorms is expected to begin by late afternoon and last into the evening hours, concluding most likely by midnight. Today's weather is driven by a strong upper-level shortwave that will be moving from northeast Louisiana very nearly up the Mississippi River. The primary concerns today are large hail, damaging wind, and the threat of tornadoes. The graphics above show the risk area for today and tonight, as well as the probability of a tornado within 25 miles of any point. For the metro area, that threat sits at about 15%.
The second round of storms will start shortly after daybreak Saturday and continue in the metro area through sometime in the early afternoon hours. The period of most concern is between 9am-1pm. This round is the more potent system and will be capable of all modes of severe weather, including strong tornadoes (EF2+), very large hail (golf ball-sized or larger), and damaging wind of 60-80 mph. These storms will be driven by a developing surface low pressure that will take a similar track to Friday's upper-level system, dragging a cold front through the area. The exact track of Saturday's low pressure will determine those areas most likely to get severe weather, including the risk of significant tornadoes. Areas just to the east of the low will be under the gun, while areas just to the west could see significant rainfall and flooding concerns. A Flash Flood Watch is in effect for Saturday.
Mid-Southerners should complete preparations for the possibility of severe weather, including checking their NOAA Weather Radio and talking with family about what to do should severe weather strike. Know where to go and what to do. Severe weather safety tips from MWN can be found here. The threat is not to be taken lightly. Be prepared, not scared.