ACUS11 KWNS 020212
SWOMCD
SPC MCD 020211
IAZ000-MNZ000-NEZ000-SDZ000-020415-

Mesoscale Discussion 2192
NWS Storm Prediction Center Norman OK
0911 PM CDT Tue Sep 01 2026

Areas affected...southeast SD...northeast NE...far southwest
MN...northern IA

Concerning...Severe Thunderstorm Watch 639...

Valid 020211Z - 020415Z

The severe weather threat for Severe Thunderstorm Watch 639
continues.

SUMMARY...A severe wind and hail risk may persist into portions of
northern Iowa and perhaps far southern Minnesota into tonight
downstream from Severe Thunderstorm Watch 639. Convective trends are
being monitored for possible downstream watch issuance.

DISCUSSION...A supercell moving from northeast NE into southeast SD
over the past 30-60 minutes has produced significant wind gusts as
an RFD surge occurred. Since then, radar presentation has become a
bit more messy and 7-9 km CAPPI has decreased. Nevertheless,
additional convection is ongoing to the south, with new updrafts
noted just to the north of this cell. The downstream airmass remains
strongly unstable, with a corridor of 2500+ J/kg MLCAPE indicated in
latest mesoanalysis. Furthermore, favorable shear will persist over
the region. While inhibition may modestly increase with onset of
nocturnal cooling, the overall environment will remain favorable for
organized convection with some continued severe risk.

Most CAMs guidance has been further north in the depiction of
convection and eventual development of an MCS. However, a surface boundary/low-level convergence zone is noted over far northern IA,
with northeasterly low-level flow into southern MN. If upscale
growth occurs, it may tend to be a bit south of where CAMs guidance
has been consistently showing. Convective trends will continue to be
monitored and a downstream watch may be needed in the next hour or
so.

..Leitman.. 09/02/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!_tIHy57-GgJpwcOD8Maiq8UQq1KPmoGuYUwK5fYF1TwrmsWUISMcqens3AnTlTHM2pNU_N3bCSY5TkqENp2x1eFzBco$ for graphic product...

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

LAT...LON 43209763 43689563 43759413 43509346 42999353 42609388
42399512 42269671 42139763 42199816 42379826 43209763

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN


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