MD 0574 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR CENTRAL/EASTERN MO…WEST-CENTRAL IL
Mesoscale Discussion 0574 NWS Storm Prediction Center Norman OK 1225 PM CDT Thu Apr 20 2023 Areas affected...Central/Eastern MO...West-Central IL Concerning...Severe potential...Watch likely Valid 201725Z - 201930Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorm coverage is expected to increase along and ahead of a cold front moving through the region over the next hour or two. Large hail and damaging gust are the main threats, although low-probability potential for tornado exists as well. DISCUSSION...Recent surface analysis places a low over north-central IA, with a cold front extending southward through south-central IA and then back more southwestward from north-central MO through southwest MO/northeast OK. Convection has begun to deepen along and ahead of this cold front as the air mass gradually destabilizes. Current surface observations reveal temperatures in the mid to upper 70s across central MO where skies briefly cleared, with slightly lower temperatures to the south over south-central MO and to the north into west-central IL. Dewpoints are in the upper 50s to low 60s areawide. Current mesoanalysis suggests these conditions have largely eroded the convective inhibition. As a result, storm coverage is expected to gradually increase over the next hour or two. Steep mid-level lapse rates remain in place over region, which should help support robust updrafts once thunderstorms initiate. Additionally, deep-layer shear is strong enough to support some updraft organization/rotation. Primary severe risk is expected to be large hail and strong downdrafts. Some tornado potential also exists, but the veered low-level flow should keep this potential low. The only exception is across far northeast MO and far west-central IL, where surface winds remain backed behind an outflow boundary. ..Mosier/Grams.. 04/20/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PAH...ILX...LSX...DVN...SGF...EAX... LAT...LON 37059370 40489170 40258973 36899091 37059370
