Mesoscale Precipitation Discussion 0488
NWS Weather Prediction Center College Park MD
1001 PM EDT Fri Jun 20 2025

Areas affected...eastern North Dakota, northern Minnesota,
northwestern Wisconsin

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

Valid 210200Z - 210800Z

Summary...Convection is expected to rapidly deepen and expand in
coverage across the discussion area in the 03-08Z (10p-3a CDT)
timeframe.  These storms will exhibit mergers and localized
training, with a risk of 2 inch/hr rain rates and a few areas of
flash flooding.

Discussion...Intense, deep convection has begun to quickly forward
propagate eastward across southwestern South Dakota.  Meanwhile,
isolated cells have formed on the nose of strengthening low-level
flow across eastern South Dakota, with supercellular structures
noted near Jamestown, ND.  These storms are exhibiting a limited
flash flood risk at the moment, with fast storm motions across
western North Dakota and isolated storm coverage in eastern North
Dakota both limiting the spatial extent of any heavy rainfall.  A
few spots of 2 inch/hr rain rates near Jamestown could prompt
isolated flash flood issues in the short term.

Over time (more likely after 03Z/10p CDT), increasing low-level
flow across the eastern Dakotas and strong speed convergence along
the nose of that low-level flow across northern Minnesota will
combine with strong instability (1500-4000 J/kg MLCAPE) to produce
widespread thunderstorm activity.  These storms should eventually
concentrate along an axis from near/north of Fargo to ner Duluth. 
They'll also form in close enough proximity to promote occasional
mergers and localized training, with spots of 2 inch/hr rain rates
expected at times.  Additionally, storms should eventually merge
with upstream convection across North Dakota, providing further
opportunity for prolonging of heavy rain rates at any one spot. 
Widespread 1-3 inch rainfall totals are expected beneath the
convection, with local amounts of 5 inches possible where
training/mergers are most pronounced.  These rates will fall on
areas of 1-2 inch/hr FFG thresholds (lowest along the ND/MN border
and across northeastern Minnesota), with exceedence expected at
times.  Flash flooding is possible in this scenario.

Cook

ATTN...WFO...BIS...DLH...FGF...GRB...MPX...MQT...

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

LAT...LON   48909458 48399232 47819106 47079065 45809004
            45429061 45729145 46589408 46639663 46399986
            46820093 47540036 47839969 48409860 48889700