AWUS01 KWNH 131123
FFGMPD
MOZ000-ARZ000-OKZ000-KSZ000-131700-

Mesoscale Precipitation Discussion 0874
NWS Weather Prediction Center College Park MD
722 AM EDT Tue Aug 13 2024

Areas affected...Southeast KS...Southwest MO...Northeast
OK...Northwest AR...

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

Valid 131130Z - 131700Z

SUMMARY...Decaying MCS with a few more hours of WAA training along
the northern side of strengthening bow echo allowing for 2-4"
totals and possible flash flooding.  Very intense short-term rates
with 1-2" in 15-30 minutes with the bow may be a flooding concern
in prone or urban settings.

DISCUSSION...Regional RADAR mosaic depicts a well defined
MCV/parent shortwave that has become well displaced in the
decaying shield precipitation WNW of the strengthening effective
triple point/new MCV near Marion/Chase county, KS.  A impressive
bowing segment is surging ESE into SE KS, with a broadening
upstream edge across south-central KS within the MCS anti-cyclonic
rotor.   While strong moisture flux convergence will quickly turn
with very short-duration resulting in 1-2" of rainfall in 15-30
minutes likely only resulting in flooding in traditionally prone
or urban settings. 

Of greater potential for flash flooding are within the bookends of
the MCS; the upwind southern anti-cyclonic rotor is starting to
have broadening convective elements being more exposed to the
southwesterly LLJ and expanding moisture convergence orthogonal to
the mean motions as the MCS enters a bit more NW to SE motions in
the 500-1000 thickness pattern (directing toward SW MO/NE OK). VWP
shows increasingly unidirectional inflow still at 25-35kts from
925-700mb advecting an axis of enhanced conditionally unstable air
with MUCAPE of 1500-2000 J/kg across north-central OK.  This may
result in an area of enhanced 2-3" totals into the southern Flint
Hills and perhaps northern Osage county.

The other location remains with the stronger WAA along/ahead of
the MCV on the cyclonic rotor; here, strengthened flow and
directional convergence results in the greatest moisture flux to
the system and should support 2-2.5"/hr rates particularly near
the transferred MCV.  However, recent trends show a shortening of
the downstream convergence and convective development.  There may
be two factors involved, the first: utilizing EAX VWP, downstream
winds are weaker at less than 10kts with even some lesser than
desirable southerly component.  The second is related to a reduced
instability pool downstream into MO.  RAP analysis suggests values
of 500-1000 J/kg exist, but strengthening CINH fields in
combination with weakening isentropic ascent on the effective warm
front may reduce the length of the WAA wing and therefore
training/repeating potential as the wave passes.  Still, the risk
of 2-4" totals in 2-3hrs will continue to pose a flash flooding
risk  as the MCS slowly decays through the remainder of the
morning.   

Gallina

ATTN...WFO...EAX...ICT...LZK...OUN...SGF...TOP...TSA...

ATTN...RFC...ABRFC...LMRFC...MBRFC...NWC...

LAT...LON   38809660 38669435 37999226 36829149 36139183 
            35689270 35689382 35919492 36459618 37199736 
            38289764 
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