A multi-pronged cold season storm system will march east across the country, bringing severe weather chances from the Plains into the South and a whopper of a snowstorm to the Northern U.S. The severe weather threat will include a risk for tornadoes, especially on Tuesday in the South.

Today’s tornado risk as outlined by the Storm Prediction Center.

Tornadoes Possible After Dark Tonight: Expect storms to form well after sunset tonight, perhaps as late as 10-midnight in the eastern portions of the High Plains. These storms will quickly crowd up and go at least somewhat linear, but a threat for tornadoes will exist given the strong low-level wind shear.

  • In addition to the tornado threat, damaging winds will be possible with the line as it moves east.
  • Hail should not be a huge threat except perhaps early on as storms are initially cellular. Hail sizes shouldn’t be too big regardless.
  • The environment features some really low cape but strong wind shear, which is very typical this time of year.

Expect storms to form in a band/linear complex with time tonight. A short window of more cellular modes is possible, but the wind shear vectors and degree of forcing both suggest crowded/linear modes will dominate with time.

Wind shear and instability tonight will certainly be sufficient for severe weather. It is actually possible some places in the risk area see rising temperatures through the night.

Tomorrow’s tornado threat from the SPC centers the tornado risk along/south of I-20 from Texas to Mississippi tomorrow.

Threat of Strong Tornadoes Tomorrow: Strong tornadoes will become increasingly likely across the South tomorrow, from extreme East Texas into Louisiana and into Mississippi. A line of storms will exist along the advancing cold front through the day, but more storms could form just ahead of this band, especially later in the day.

  • The wind shear is fairly strong tomorrow, so any isolated storms will pose the threat of strong tornadoes.
  • It is possible no storms form ahead of the advancing cold front if thick clouds exist through the day. Even if so, a threat of tornadoes along the line will still exist.
  • Watch for the degree of cloud breaks through the day tomorrow as one sign of whether isolated storms in the open warm sector are likely to organize into dangerous supercells.
  • While the tornado threat will exist through the day, the environmental peak will likely occur near and just after dark.
  • Damaging winds will be possible with any storms along the cold front, and large hail will certainly be possible with cellular storms ahead of the line.

As of right now, instability will likely be on the lower-end of what you look for this time of year, but small cloud breaks will make a big difference either way. Wind shear is also sufficient, especially further east away from the cold front.

The environment will feature very low cloud bases (Temperature/Dewpoint spreads below 10 generally), so any isolated storms will likely pose the threat of tornadoes given the 0-1km SRH of 240-350 through the region.

As of right now, models are hinting at a mixture of storm modes through the day and into the night tomorrow. How this evolves will likely be the determining factor as to the extent of the tornado threat tomorrow.

And if severe thunderstorms are not your thing, a big snowstorm will occur in the northern Plains.

Travel Nightmare: As the low pressure moves north and east and deepens, a big winter storm will take shape on the north and west side of the advancing system. Expect major travel problems across the Central and Northern Plains into likely midweek.

  • 8-12 inches of snow is likely, especially across western Nebraska into the Dakotas.
  • Some local areas will certainly see more than a foot in that region.

As always, we’ll have much more on this system on our social media channels through the next two days.