Forecast Discussion – March 30, 2023 – Bimodal Severe Weather Outbreak Expected Tomorrow

For educational purposes only. If you live in the affected areas, please stay tuned to your local National Weather Service office for the most accurate and up-to-date information.

March 30, 2023: A bimodal outbreak of significant severe weather is expected tomorrow (Friday, March 31) from the Midwest to the Mid-South. The SPC has outlined two Moderate risk (level 4 of 5) areas, one across southeast Iowa into western Illinois and one farther south along the Mississippi River delta in northeast Arkansas, western Tennessee, and the Missouri bootheel. A strong closed upper low will migrate into the region, coupled with a deepening surface low. A broad warm sector will be in place from Iowa south to the Gulf Coast states. Semi-discrete supercells will initiate ahead of the surface low/cold front across central Iowa by early afternoon Friday with mostly a large hail threat. The (strong) tornado threat will increase farther east amid very favorable thermodynamics and strong low-level shear/vorticity along any surface boundaries. However, the amount of time that storms will remain semi-discrete may be somewhat short, limiting the strong/long-track tornado threat due to a quick transition to a more linear mode. Farther south, both the cold front and a prefrontal trough should initiate semi-discrete supercells in and around Arkansas. Intense wind profiles will be in place; if robust instability can be realized, strong/long-track tornadoes are possible.

My video on cold-core tornado environments: https://www.youtube.com/watch?v=W00SxO2UcYo

Contents
0:00 Introduction
2:07 Current observations
7:24 Model analysis (NAM, CAMs)
39:28 Analog – March 28, 2020
44:22 Analog – April 9, 2015
47:09 Summary

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