MD 0165 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR PARTS OF CENTRAL AND SOUTHERN ILLINOIS INTO WESTERN INDIANA
Mesoscale Discussion 0165
NWS Storm Prediction Center Norman OK
0547 PM CST Tue Feb 27 2024
Areas affected…parts of central and southern Illinois into Western
Indiana
Concerning…Severe potential…Watch possible
Valid 272347Z – 280115Z
Probability of Watch Issuance…40 percent
SUMMARY…Isolated storm development along the dryline is possible
early this evening. Experimental WOFS guidance and environmental
analysis suggest conditional severe potential if supercells are able
to develop.
DISCUSSION…As of 2230 UTC, regional satellite data showed towering
altocumulus deepening across parts of central IL. Located along the
dryline ahead of a subtle shortwave trough, multiple attempts at CI
appear to be underway. The environment downstream of the dryline is
conditionally favorable for deep convection, with dewpoints in the
upper 50s to low 60s F and steep mid-level lapse rates supporting
1500-2000 J/kg of MLCAPE. Considerable MLCINH (-100 J/kg from
mesoanalysis) remains in place, but if deep convection can initiate,
50+ kt of effective shear would favor storm organization with a
supercellular mode.
Hi-res and experimental forecast guidance has shown isolated storm
development early this evening over several prior runs. Should this
occur, the environment over eastern IL and western IN is favorable
for supercells capable of all severe hazards. ESRH of 300-400 m2/s2,
observed from area VWPs, may also support a risk for a strong
tornado. While the risk remains very uncertain, given dry air
entertainment and the loss of diurnal heating along the dryline,
observational trends are being monitored for a possible weather
watch. Storm development is much more likely later this evening as
the cold front and stronger forcing for ascent approach from the
west after 03z.
..Lyons/Edwards.. 02/27/2024
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…IND…PAH…ILX…LSX…
LAT…LON 37958969 37818925 38028870 38298808 38718704 39138667
39608666 39778676 39958695 40108734 40118805 40038834
39808890 39598926 39298952 38418970 37958969
