Mesoscale Precipitation Discussion 0548
NWS Weather Prediction Center College Park MD
200 AM EDT Sat Jul 28 2018

Areas affected...Southeast SD...eastern NE...Southwest
IA...Northwest MO

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

Valid 280559Z - 281059Z

SUMMARY...Convection increasing in coverage may result in some
instances of flash flooding with multiple rounds of thunderstorms
producing very heavy rain likely through 11Z. 

DISCUSSION...Regional radars are indicating multiple clusters of
elevated thunderstorms developing along an 850mb front extending
from south-central South Dakota to southeast Nebraska early this
morning.  Although instability over this region is modest with
MUCAPE on the order of 500 to 1000 j/kg, there is enough low level
forcing to support and sustain convection along this elevated
boundary with a steady low level moisture flux advecting 1.25+
inch PWs into this region.  Back-building is likely to occur with
this convection with unidirectional flow noted in the Omaha 00Z
RAOB from 850mb to 200mb. 

There is a strong signal in the latest high-res model guidance
suite for a corridor of 1 to 3 inch rainfall amounts along with
good support from recent global model guidance regarding placement
of the QPF axis.  The lowest 3-hr flash flood guidance is over
portions of south-central SD.  Flash flooding is considered
possible in this situation.

D. Hamrick

ATTN...WFO...ABR...DMX...EAX...FSD...GID...LBF...OAX...TOP...
UNR...

ATTN...RFC...MBRFC...

LAT...LON   44019958 43699845 42999702 42209611 41299511
            40359443 39849452 39579497 39649589 40079677
            40929745 42029837 42789969 43450075 43950059