Mesoscale Discussion 1741
NWS Storm Prediction Center Norman OK
0847 AM CDT Tue Jul 30 2024
Areas affected...portions of southern Iowa...northern Missouri...and
extreme west-central Illinois
Concerning...Severe potential...Watch possible
Valid 301347Z - 301515Z
Probability of Watch Issuance...60 percent
SUMMARY...Damaging gusts are possible this morning and afternoon as
a cluster of storms tracks southeast across southern Iowa into
northern Missouri and extreme west-central Illinois. A watch may be
needed this morning, though timing is uncertain.
DISCUSSION...A well organized cluster of storms currently moving
into central Iowa has produced gusts near 50 kt within the past 30
minutes or so. This activity may be somewhat elevated in the wake of
overnight convection. Nevertheless, 35-45 kt effective shear
magnitudes and MLCAPE around 1000-1500 J/kg will likely maintain
organization. While outflow from overnight convection has surged
southward to near I-70 in Missouri, the airmass has shown signs of
quick recovery, with surface dewpoints in the mid/upper 60s F noted
in 13z surface obs. Clear skies ahead of the cluster will also allow
for quick heating through the morning hours. As a result, downstream destabilization and erosion of capping is expected.
The ongoing cluster of storms may continue to gradually intensify
and pose a risk for damaging gusts into late morning/early afternoon
as the downstream airmass continue to recover/destabilize. Given the
effect of overnight convection on the airmass, there is some
uncertainty in convective evolution and timing of possible watch
issuance. Nevertheless, it appears possible a severe thunderstorm
watch could be needed this morning across parts of the discussion
area.