AWUS01 KWNH 141113
FFGMPD
MNZ000-IAZ000-NEZ000-SDZ000-141600-

Mesoscale Precipitation Discussion 1280
NWS Weather Prediction Center College Park MD
711 AM EDT Mon Sep 14 2026

Areas affected...Eastern South Dakota...Far Southwest
Minnesota...Northwest Iowa...Far Northeast Nebraska...

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

Valid 141110Z - 141600Z

SUMMARY...Northward expansion of warm-advection with approaching
mid-level energy to maintain localized 1.5"/hr rates and localized
2-3" totals as it nears lower FFG areas further east.

DISCUSSION...GOES-E 10.3um EIR loop shows the northward expansion
of the warm advective over-running induced convection shows some
overall warming as more individualized cores start to further
cool. This occurred with a secondary surge of warm-advection,
speed increase over the last hour or so noted by increased
upstream (SW) low Cu/Tcu field starting to intersect with the
first convective wave. VWP also shows a steady increase of
southerly 850mb winds while maintaining the favorable veered low
level shear environment for weak rotating updrafts. This further
helps to isolate, but concentrate moisture flux to increase
rainfall efficiency as well. Total PWats to 1.75" and a solid
remaining core of 2000 J/kg MUCAPE upstream will support localized
1.5"/hr rates occasionally ticking up toward 2" in a very
transient sense both spatially and temporally.

While areas further west over SW SD have higher FFG, the slow
eastward progression of the line will start intersecting an axis
of lower FFG values (<1.5"/hr) from Kingsbury/Brookings county south-southeastward into Western IA, where values lower further.
Forward progression will continue to be slow to allow for for
increased residency for localized streaks of 2-3" totals which
even press 3hr FFG values that range below 2.5".

To further support localized flash flooding potential, the deep
layer WAA moisture flux convergence will continue to maintain as
the core of the mid-level shortwave continues to advance
northeastward across the Dakotas ahead of the main closed low
later today. This should maintain the strong LLJ and veered
profile for a few more hours before becoming more progressive
toward 15z. Additional glancing dPVA influence may even further
more isolated thunderstorm activity upstream cross central to
east-central SD, that may intersect areas of this earlier WAA
activity, further expanding the area of isolated low-end flash
flooding risk this morning.

Gallina

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

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

LAT...LON 45209749 45109614 44359545 42989489 42289481
41849549 41939651 42479717 43429789 44209859
44919846

$$
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