2020-04-08 EVENT: IA/IL/MO/IN/KY/AR/TN

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Jesse Risley

Staff member
Apr 12, 2006
Macomb, IL
I expect today to be similar to yesterday in terms of regionally discrete supercells that break out by early to mid-afternoon in association with W/NW flow tied to the upper-level system that is making its way across the northern CONUS, albeit with the greatest activity concentrated further west and southwest of yesterday's show. A more anemic area of surface low pressure system should migrate to near KEOK by early this afternoon as a cold front sags southward into EC Iowa, but it is forecast to strengthen a bit as it moves into central IL by later afternoon to early evening. As surface temperatures continue to warm rather impressive lapse rates will exist across the area owed to the very steep vertical temperature gradients aloft, with some models progging values in the range of 9-10 C/km. While low-level shear is weak, it appears there will be enough shear aloft for ample mid-level rotation, coupled with notable hydrolapses on some skew-t profiles between H85 and H7, to facilitate some rather regionally magnanimous severe hailers today, particularly across parts of IL into IN and N KY. Convection should conglomerate into clusters and QLCS activity as the convection spreads E/SE. Damaging winds remain an ancillary threat, with a rather marginal, though probably not non-zero tornadic potential, particularly of the mesovortex variety on the leading edge of bowing segments INVO localized low-level shear maxima.