AWUS01 KWNH 260747
FFGMPD
IAZ000-NEZ000-SDZ000-261346-

Mesoscale Precipitation Discussion 0518
NWS Weather Prediction Center College Park MD
347 AM EDT Thu Jun 26 2025

Areas affected...much of Nebraska, western Iowa

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

Valid 260746Z - 261346Z

Summary...Flash flood potential continues - especially near Grand
Island, NE where 5-10 inches of rainfall has occurred over the
past 12 hours.

Discussion...Extensive flash flood impacts have occurred near
Grand Island, NE earlier, where a couple of convective bands began
to train over the region and produce 3-6 inches of rainfall over
the past 6 hours.  Since that time, upscale growth and slight
weakening of convection across south-central Nebraska has enabled
the heaviest rain to propagate just east of the Grand Island
region.

Unfortunately, an upstream mid-level impulse and convergence on
the nose of 40-kt 850mb flow over Kansas to produce renewed
convection across west-central Nebraska.  These storms will allow
for continued rainfall and perhaps another 1 inch of rain on top
of prior significant rainfall, potentially exacerbating impacts
near the Grand Island area.  This additional rainfall risk will
persist for at least another 3 hours or so (through 1030Z/5:30am
CDT) until the upstream mid-level impulse passes the region.

Additional rainfall will persist east of Grand Island through
Columbus, Omaha Metro, and portions of western Iowa through 13Z/8a
CDT.  Rain rates should remain relatively low with this activity
due to modest instability and appreciable (30-kt) movement,
although prior rainfall (as much as 3-5 inches along this axis)
have lowered FFG thresholds and made ground conditions
sensitive/conducive for excessive runoff.  Another 1-2 inches of
rainfall along this axis could contribute to isolated/continued
flash flooding this morning.

Cook

ATTN...WFO...DMX...FSD...GID...GLD...LBF...OAX...

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

LAT...LON   43109403 42439339 41599368 40889554 40269810 
            40150037 40600098 41470061 42119875 42659595 
            
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