Severe Threat to Increase This Weekend, Next Week

The severe threat appears to be increasing this weekend, and at least one, if not two chances of severe weather look to be on the books for next week. Sunday's severe threat will bring all hazards to southern Illinois, including tornadoes.

SPC Day 3 Convective Outlook

The Storm Prediction Center has placed an Enhanced Risk (Level 3/5) across the entire area for Sunday. It is unclear exactly what drives this risk, though the discussion does mention all severe modes will be possible.

There has been a notable shift northward in the track of the center of low pressure, which will allow for more extensive moisture return, with medium range models indicating dew points soaring into the mid 60s, quite high for this time of year.

6Z NAM 2m Dew Points valid 7p Sunday

The northerly shift in the low has also allowed for an increase in instability. Most unstable Convective Available Potential Energy (MU-CAPE) values of 1-2,000 j/kg yield moderate instability.

6Z NAM MU-CAPE valid 7p Sunday

Additionally, modest 30-50 knots of sfc-500mb bulk shear will support at least a limited tornado potential, though shear has been trending upward over the past model runs, so the tornado threat may also be on the rise. Steep lapse rates will support a large hail threat, some hailstones may exceed 2 inches in diameter. Additionally, damaging wind gusts will be a concern, some of which could exceed 70 mph. Analog based forecasts continue to show a severe threat across the region.

CIPS Analog-Based Severe Weather Probabilities (GEFS 2025032800Z)

Beyond day 3, the SPC has introduced a day 6 slight risk for the area, indicating yet another chance for severe weather on Wednesday 4/2.

SPC Day 6 Severe Outlook

The SPC mentions that this system will have the potential to again produce widespread all hazards severe weather, though they aren't certain exactly where. Analog based forecasts again center the severe area over our area.

CIPS Analog-Based Severe Weather Guidance (GEFS 2025032800Z)

Beyond day 6, the large-scale features of the atmosphere become less certain, thus no areas have been introduced, though analog based guidance continues to suggest yet another severe threat across the area on day 8.