MD 0524 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR PORTIONS OF NORTHERN/CENTRAL ARKANSAS…SOUTHERN/CENTRAL MISSOURI AND WEST-CENTRAL ILLINOIS
Mesoscale Discussion 0524
NWS Storm Prediction Center Norman OK
1139 AM CDT Sat Apr 15 2023
Areas affected...portions of northern/central
Arkansas...southern/central Missouri and west-central Illinois
Concerning...Severe potential...Watch likely
Valid 151639Z - 151915Z
Probability of Watch Issuance...95 percent
SUMMARY...Large hail (some greater than 2 inch diameter), damaging
gusts and a few tornadoes are possible this afternoon across
central/northern Arkansas, southern/central Missouri and
west-central Illinois. A watch will likely be needed in the next
couple hours.
DISCUSSION...Visible satellite imagery shows deepening cumulus ahead
of the eastward-advancing cold front over the NE OK/SW MO/NW AR
vicinity at midday. Temperatures have warmed into the mid/upper 70s
amid upper 50s/low 60s F dewpoints. This has aided in weakening
inhibition and MLCAPE increasing to around 1500-2000 J/kg amid a
plume of steep midlevel lapse rates (8-8.5 C/km). Increasing
large-scale ascent and frontal convergence will likely support
initial thunderstorm development within the area by 19z.
Downstream from this destabilizing airmass toward central MO and
west-central IL, stronger inhibition remains. This is partly due to
elevated morning convection. However, clearing behind morning
convection will allow for continued heating and airmass recovery
ahead of developing convection over western portions of the
discussion area.
Supercell vertical wind profiles will favor initial semi-discrete
activity. Very steep lapse rates, large instability and elongated
hodographs suggest very large hail will be possible with this
initial activity. Steep low-level lapse rates and modest low-level
shear also will support damaging gusts. With time and eastward
extent, convection may become more of a mixed mode of semi-discrete
supercells and clusters/lines as upscale development into a QLCS
appears likely. Low-level shear is expected to remain modest, but
small and favorably curved low-level hodographs could support some
risk for a few tornadoes, especially south of the I-44 corridor in
MO into north-central AR. A watch will likely be needed in the next
couple of hours.
..Leitman/Grams.. 04/15/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PAH...ILX...MEG...LSX...LZK...SGF...EAX...TSA...
LAT...LON 35109137 34839187 34719239 34659310 34879398 35179435
35969467 36619466 36869463 37439451 38179381 39239229
39609131 39679081 39619017 39288981 38878972 38378972
37938981 35929071 35109137
