####018003188#### ACUS01 KWNS 071630 SWODY1 SPC AC 071629 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Sun Apr 07 2024 Valid 071630Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS A PORTION OF THE MID-MISSISSIPPI VALLEY CENTERED FROM THE MISSOURI BOOTHEEL TO WESTERN PARTS OF KENTUCKY AND TENNESSEE... ...SUMMARY... Widely scattered strong/isolated severe thunderstorms are possible during the late afternoon to mid-evening in the lower/mid Mississippi Valley. ...Mid/lower Mississippi Valley area... While dewpoints remain in the 30s and 40s across the SLGT risk area late this morning, low-level moisture advection is ongoing ahead of the advancing cold front, with low to mid 60s dewpoints now observed across central and southern portions of Arkansas. As the front advances eastward, and the more favorable low-level theta-e airmass continues advecting northward, filtered heating will support modest destabilization, with afternoon mixed-layer CAPE values rising into the 500 to 1000 J/kg range. Stronger ascent will remain just north of the SLGT risk area, as a lobe of vorticity rotating through cyclonic southwesterly flow aloft on the southeastern side of closed upper low over Nebraska crosses Illinois/Indiana this afternoon. Still, scattered convective development is expected to begin by mid to late afternoon across the Mid Mississippi Valley, and southward into the Delta region, in focused low-level ascent near the cold front. While modest CAPE will likely limit severe potential, the deep-layer wind field (veering and increasing favorably with height across the pre-frontal warm sector) will likely augment a few of the stronger updrafts, suggesting that a few storms will become capable of producing hail and/or damaging winds. A tornado or two will also be possible, with hodographs indicating favorable helicity with any right-moving supercell. Severe potential should peak through late afternoon, and then gradually diminish this evening as the boundary layer cools, and the cold front weakens with time. ...Parts of central/southeastern Iowa and vicinity... As the weakening/vertically stacked low shifts northeastward out of Nebraska and across northwestern Iowa this afternoon, continued daytime heating of a marginally moist (40s dewpoints) boundary layer, residing beneath rather steep mid-level lapse rates will continue to facilitate weak destabilization. Thunderstorms have developed late this morning across portions of northern and central Illinois, and across north-central Iowa and into adjacent southern Minnesota. By mid afternoon, new convective development is expected along the occluded front currently moving northeastward across the Nebraska/Iowa border/Mid-Missouri Valley at this time, as it shifts into central and southeastern Iowa. While the evolving, low-topped storms should remain largely sub-severe, a strong to severe wind gust or two, and even a brief tornado, will be possible, through late afternoon/early evening. ..Goss/Gleason.. 04/07/2024 $$