MD 1729 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR EASTERN ILLINOIS INTO CENTRAL INDIANA
Mesoscale Discussion 1729
NWS Storm Prediction Center Norman OK
0358 PM CDT Mon Jul 29 2024
Areas affected…eastern Illinois into central Indiana
Concerning…Severe potential…Watch possible
Valid 292058Z – 292330Z
Probability of Watch Issuance…40 percent
SUMMARY…Thunderstorm development appears probable in the next 1-2
hours across eastern Illinois and far western Indiana. Watch
issuance may be needed later this evening if robust supercells
and/or an organized line can be established.
DISCUSSION…GOES visible imagery shows slowly building cumulus
along a diffuse trough axis to the south of a weak surface
low/remnant MCV. Air mass recovery continues to the east of the
trough axis with temperatures climbing into the low to mid 80s with
dewpoints climbing well into the 70s. This is promoting a gradual
expansion of MLCAPE values to the northeast with values ranging from
500-2000 J/kg from southern lower MI southward into southern IL/IN.
The expectation is for thunderstorm development in the next couple
of hours along the trough axis as the air mass continues to
destabilize. 30-45 knot northwesterly mid-level winds on the
southern periphery of the MCV combined with northerly surface winds
are supporting effective bulk shear values near 40-50 knots nearly
orthogonal to the trough axis. This may support a few initially
discrete cells with an attendant large hail threat. With time
upscale growth into an organized MCS appears likely given weaker
wind shear near the low, which will favor thunderstorm clustering
before storms propagate southward along the buoyancy gradient into
the better deep-layer wind shear. As such, the potential for severe
winds may increase later this evening across eastern IL into central
and southern IN, and possibly into the lower OH River Valley.
Convective trends will be monitored, and watch issuance may be
needed to address this concern.
..Moore/Hart.. 07/29/2024
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…ILN…LMK…IWX…IND…PAH…LOT…ILX…
LAT…LON 39858876 39988833 40258776 40498747 40698718 41008693
41048659 40968627 40848585 40618540 40358502 40088481
39818472 39578472 38888497 38648513 38468535 38398573
38348623 38358646 38468713 38578763 38758801 39048834
39348864 39858876
