Mesoscale Precipitation Discussion 0311
NWS Weather Prediction Center College Park MD
834 PM EDT Wed Jun 03 2026

Areas affected...Eastern South Dakota...Southwest Minnesota...Ext.
Northwest Iowa...

Concerning...Heavy rainfall...Flash flooding possible

Valid 040035Z - 040600Z

SUMMARY...Increasing convective coverage and orientation to the
flow suggest increasing potential for repeating cell tracks and
increasing rainfall efficiency to support 1.75"/hr and localized
streaks of 2-3" totals.  Widely scattered incident or two of
localized flash flooding is possible through early overnight
period.

DISCUSSION...00z surface analysis continues to depict a surface
low along the Missouri River between KPIR and K9V9 with a region
of backed surface flow and enhanced moisture from northeast NE
into SE SD, including a stark 2-4 degree increase near/north of
HON/K6E5; additionally the cold front is starting to advance in
the last few hours.  This localized maximum of low level moisture
was also between a convective cluster from the south and
approaching supercell canopy providing the last few hours of
insolation to maintain a pocket of enhanced conditionally unstable
air. VWP and low level observational trends denote an increase in
surface to boundary layer southerly flow through much of the area
of concern up to 15-25kts from sfc to 850mb, providing enhanced
flux and some WAA.  MLCAPEs of 2000-2250 J/kg and Total PWats of
1.5-1.7" with the strength of flux suggests 1.5-1.75"/hr rates are
likely to become more common with broadening up/downdrafts cores.

Aloft, GOES-WV shows strong cirrus streaks indicative of the jet
streak across northeast SD into SW ND/NW MN. This is expected to
further strengthen to 100kts after sunset placing much of the MPD
area of concern into favorable right entrance ascent region
allowing for upscale growth into a broader complex.  Regional
RADAR denotes this increase in activity east/downstream of the
supercell in Tripp county; as well as the increasing dewpoint line
from Spink to Deuel counties.   Overall, deep layer steering is
also increasing with the aforementioned jet strengthening, likely
to limit any particular cell's residency except  right-mover
supercells.  The concern is that the expansion of development is
generally parallel to the deep mean flow, suggestive of increasing
potential for repeating/training.  As such, streaks of 2-3" totals
across these two west to east axes will have the greatest
potential of exceeding the 1-3hr FFG values in the region and
present a localized flash flooding incident or two possibly
through the early overnight period.

Gallina

ATTN...WFO...ABR...FSD...MPX...UNR...

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

LAT...LON   45739710 45729615 45509504 45009436 44059454
            43369536 43059684 43019877 43319989 44409979
            45409795