992
AWUS01 KWNH 310049
FFGMPD
MNZ000-SDZ000-310647-

Mesoscale Precipitation Discussion 0900
NWS Weather Prediction Center College Park MD
848 PM EDT Thu Jul 30 2026

Areas affected...eastern South Dakota into western Minnesota

Concerning...Heavy rainfall...Flash flooding likely

Valid 310047Z - 310647Z

Summary...Flash flood potential will continue to spread eastward
into southwestern Minnesota while persisting in much of South
Dakota, though the duration and extent of this risk is uncertain.

Discussion...A complicated surface pattern exists across the
discussion area.  A couple of maturing convective complexes exist:
1) from just northwest of Benson, MN southwestward to near Huron
and on to near Mobridge, SD and 2) a second, more quickly moving
MCS from near Faith to near Phillip, SD.  At their current pace,
each of these complexes were expected to merge across central into
east-central South Dakota, prolonging rain rates in areas that
were already experiencing 1-3 inch/hr totals due to slow storm
movement.  These trends suggest a continued flash flood threat
particularly with the lead MCS from near Huron to Mobridge given
slow cell movement and potential for more than one round of heavy
rainfall.

Further complicating this pattern is the presence of subtle
low-level drying downstream across Iowa and far southern
Minnesota, which has resulted in negligible instability in those
areas.  Furthermore, a more mature, intense MCS over
central/eastern Nebraska will stabilize the low-levels into
south-central South Dakota via convective overturning.  These
factors will likely impact MCS maintenance/propagation over
eastern South Dakota into western Minnesota, although the
well-organized nature of the MCS in eastern South Dakota suggests
at least another 3-5 hours of persistence along with slow eastward
movement.  Should 2-3 inch/hr rain rates continue to materialize
(plausible given slow cell motions in some areas and 2.1+ inch PW
values), areas of flash flooding will remain possible.  Eastward
maintenance of the convective complexes into southwestern
Minnesota is expected, although persistence beyond State Highway
15 in Minnesota remains uncertain.  Flash flooding is expected on
at least an isolated basis in this regime.

Cook

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...ABR...FGF...FSD...MPX...

ATTN...RFC...KRF...MSR...NWC...

LAT...LON   45819638 45729529 45169465 44619438 43979436
            43629600 43789943 44000030 44650035 45169982
            45199854 45499719