Strong Tornadoes Likely Across South

Strong tornadoes are likely today into tonight for parts of the South extending northward into Tennessee and southern parts of Kentucky. This will be the first severe thunderstorm and tornado outbreak of the year, which is why the Storm Prediction Center has issued its first moderate risk of the year (see Fig. 1). The moderate risk extends from south-central Tennessee into northern & central Mississippi and northwestern Alabama. Surrounding the moderate risk is an enhanced risk which extends from southern Kentucky southward into northeastern Louisiana.

Fig. 1: Thunderstorm outlook for Saturday (from the SPC)

A strong, negatively tilted shortwave trough is advancing eastward this morning from the Southern Plains. With this trough is a strong jet aloft. Ahead of the trough and jet, across the South, 60 & 70 degree dewpoints have already surged northward due to a strong surface low that is deepening in the Plains (this low is responsible for the blizzard conditions from the Texas Panhandle into Iowa). This will set the stage for very intense, rotating updrafts this afternoon. At this hour (this morning), intense thunderstorms have already developed across western Arkansas extending southward into northwestern Louisiana and eastern Texas. These storms will race eastward into the Mississippi Delta by this afternoon. At that point, all the atmospheric conditions will be primed for strong tornadoes. Along with strong tornadoes (see Fig. 2), large hail (see Fig. 3) and damaging winds (see Fig. 4) are possible. Other hazards are lightning and flash flooding.

Fig. 2: Tornado probabilities for Saturday (from SPC)
Fig. 3: Hail probabilities for Saturday (from SPC)
Fig. 4: Damaging wind probabilities for Saturday (from SPC)

Here is a snapshot of what the radar may look like early this afternoon (see Fig. 5) and by early evening (see Fig. 6). Notice the primary broken line of thunderstorms along with the isolated storms ahead of this line. It is possible tornadoes may exist in the line of thunderstorms with discreet supercells (producing tornadoes) out ahead of the main line.

Fig. 5: Simulated radar early Saturday afternoon
Fig. 6: Simulated radar early Saturday evening

Make sure you are weather-alert today & tonight. Have a plan in place in case a warning is issued for your area!