900
ACUS11 KWNS 090034
SWOMCD
SPC MCD 090033
ILZ000-IAZ000-090230-

Mesoscale Discussion 2272
NWS Storm Prediction Center Norman OK
0733 PM CDT Tue Sep 08 2026

Areas affected...parts of south central and southeastern Iowa

Concerning...Severe potential...Watch unlikely

Valid 090033Z - 090230Z

Probability of Watch Issuance...20 percent

SUMMARY...A loosely organized cluster of storms may continue to pose
a risk for severe wind and hail another hour or two, but seems
likely to weaken as it approaches the southeastern Iowa Mississippi
River vicinity toward 10-11 PM CDT.  At this point a severe weather
watch is not anticipated, but trends will continue to be monitored.

DISCUSSION...A strong downburst, and perhaps an associated
developing meso-beta scale cyclonic circulation, associated with
intensifying convection initially above/to the cool side of a fairly
sharp low-level baroclinic zone, overtook the boundary across and
east of the Des Moines area 1-2 hours ago.  This remains the case as
activity propagates east-southeastward near and to the northeast of
the Knoxville IA vicinity.

Probably initially supported by an influx of seasonably moist
boundary-layer air characterized by CAPE on the order of 2000-3000
J/kg, it remains unclear how long this will be maintained into this
evening.  There has been some recent increase in surface dew points
along/just ahead of the convection and wave along the boundary,
accompanied by an increase in initially more modest CAPE toward the
Mississippi River.  However, with little in the way of cooling
aloft, and at least gradually surface cooling underway, it remains
unclear how long large-scale and mesoscale ascent will overcome
increasing inhibition.

..Kerr/Gleason.. 09/09/2026

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...DVN...DMX...

LAT...LON   41519351 41749253 41909240 41889172 41809094 41449030
            40899087 40809202 40869243 41139333 41519351

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN