ACUS11 KWNS 172343
SWOMCD
SPC MCD 172343=20
IAZ000-MNZ000-180145-

Mesoscale Discussion 1980
NWS Storm Prediction Center Norman OK
0643 PM CDT Sun Aug 17 2025

Areas affected...northern iowa and southwestern Minnesota

Concerning...Severe potential...Watch possible=20

Valid 172343Z - 180145Z

Probability of Watch Issuance...40 percent

SUMMARY...Occasionally intensifying supercell structures posing a
risk for short-lived tornadoes and locally damaging wind gusts may
continue into the 8-10 PM CDT time frame, before diminishing. It is
not clear that a severe weather watch is needed, but trends will
continue to be monitored for this possibility.

DISCUSSION...A stalled surface frontal zone has become the focus for
increasing thunderstorm development over the past hour or so, as
lift associated with focused low-level convergence and weak warm
advection have been sufficient to overcome any lingering late
afternoon mid-level inhibition. Although lower/mid-tropospheric
lapse rates are mostly modest, at best, seasonably high
boundary-layer moisture content is contributing to sizable CAPE.=20
Low-level buoyancy associated with surface dew points in the
mid/upper 70s is potentially supportive of large near surface
updraft accelerations, as weak to modest, clockwise curved low-level
hodographs contribute to updraft rotation. Deep-layer shear appears
marginal for sustained supercell structures, but isolated to widely
scattered stronger storms may continue to pose a risk for generally
short-lived tornadoes and localized damaging wind gusts into the
01-03Z time frame, before inhibition for boundary-layer parcels
increases with the onset of boundary-layer cool.

..Kerr/Smith.. 08/17/2025

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!4MjVZ8_q9SRSf9EgspjaxY_x1QA4J6SM_8_CMW9_MQPQl0LDOf-mnjE5cYh3DHaOHPNMzL2QU= w-8KK9i8SYseWthV4I$ for graphic product...

ATTN...WFO...DVN...ARX...MPX...DMX...FSD...

LAT...LON 44279511 43719313 43139205 42809113 42189073 42209252
42719404 43679601 44279511=20

MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN


=3D =3D =3D
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