ACUS11 KWNS 181948

SWOMCD

SPC MCD 181947 

IAZ000-MNZ000-SDZ000-182145-



Mesoscale Discussion 2025

NWS Storm Prediction Center Norman OK

0247 PM CDT Tue Aug 18 2026



Areas affected...Far southeast South Dakota into southern Minnesota

and northern Iowa



Concerning...Severe potential...Watch possible 



Valid 181947Z - 182145Z



Probability of Watch Issuance...40 percent



SUMMARY...While uncertainty in storm coverage remains, large hail

and damaging winds would be possible with storms that may develop

along the cold front. Convective trends will be monitored through

the afternoon for a possible watch.



DISCUSSION...Cumulus have been deepening near a weak mesoscale low

in southeast South Dakota. Additional cumulus towers have been

observed along the cold front farther east, though convergence is

much weaker and agitated cumulus have not been long lived. With

around 50 kt of shear and destabilization occurring south of the

front, large hail (potentially near 2 in.) and damaging winds would

be possible. The main question will be how many storms will be able

to form this afternoon. The weak surface convergence across much of

the front and upper-level clouds moving in from the west limit

confidence in this regard. Some CAM guidance has suggested storm

development along the front may be delayed until late

afternoon/early evening when a stronger southerly surge of the front

is expected. Convective trends will need to be monitored for a

possible watch.



..Wendt/Guyer.. 08/18/2026



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



ATTN...WFO...MPX...DMX...FSD...



LAT...LON   44159704 44409669 44019512 43939408 43669375 43429368

            42739352 42499362 42499396 42569417 42629467 43159654

            43899706 44159704 



MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH

MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN