077 

AWUS01 KWNH 182302

FFGMPD

MOZ000-IAZ000-KSZ000-NEZ000-190500-



Mesoscale Precipitation Discussion 0187

NWS Weather Prediction Center College Park MD

701 PM EDT Mon May 18 2026



Areas affected...Southwest IA...Southeast NEB...Northwest

MO...Central & Northeast KS...



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



Valid 182300Z - 190500Z



SUMMARY...Strong moisture flux convergence will help to spur

upscale growth from individual supercells to larger clusters with

increasing rainfall potential and coverage.  Rates of 2"/hr+ and

localized totals of 2-4" (isolated 5"), especially across areas

recently saturated are likely to result in increasing incidents of

flash flooding.



DISCUSSION...22z surface analysis and RADAR mosaic have changed

very little over the last few hours though the dryline has surged

out of the OK/TX panhandles and helped concentrate southerly moist

flux to expand convective initiation well into south-central KS. 

Main clusters of supercells have are at bit more progressive out

of southeast NEB with some eastward turning and increasing

coverage and has started to move out of MPD 185 area of concern

into SW IA and far NW MO.   Additionally, the remainder of the

cold front from the northern inflection E of Lincoln, NEB and

secondary low near Salina, KS has filled in with broadening

up/downdrafts; as such total PWats have increased along the cold

front as the total column moistens with this increasing coverage. 

Tds in the 70s and sub-boundary layer LPW values near 1" along

with 20-30kts of southerly flow continue to provide strong

moisture flux to encourage increasing rainfall efficiency over the

next few hours.



GOES-E WV shows the upper level jet streak is currently rounding

the base of the negative tilt up-level trof over the Northern

Plains and as a result, upper level divergence pattern will

further increase over the next few hours within strengthening DPVA

and right entrance ascent patterns across the frontal zone.  This

should support further upscale growth of the cells toward clusters

as we near sunset.   Cold pool generation, right-turning

supercells, should support further storm-scale interaction for

more eastward propagation allowing some increased short-term

training/repeating (as noted with clusters in NW MO already).  As

such localized streaks of 2-4" totals will become more likely.



Across the MPD area a broadening/divergent of the 500-1000

thickness fields suggests east to southeast forward propagation

with time as well; increasing orthogonal flanking line

intersection to expand back-building potential.  This

slowing/turning could be the greatest further south along the

upstream edge near the nose of the dryline/cold front where

steering flow is just a tad weaker overall aloft and support

longer residency times.   Of course, south-central KS will require

this longer residency given the area has missed out on the

complexes/heavy rainfall over the weekend. 



While severe/tornadic hazards remain the primary concern

currently, this will transition toward flash flooding and given

the majority of the area (north of 38.5N latitude) has FFG values

at or below the hourly expected rates (1-1.75"/hr) and generally

less than 2.5"/3hrs.  As such, incidents of flash flooding will

become more likely and with greater overall coverage.  Hi-Res CAMs

including the WoFS/HRRR continue to suggest very intense

sub-hourly totals (1.5"/15 minutes per HRRR) and isolated totals

of 5". 



Gallina



...Please see www.wpc.ncep.noaa.gov for graphic product...



ATTN...WFO...DMX...EAX...ICT...OAX...TOP...



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



LAT...LON   41899371 41709307 41259253 40579249 40039284 

            39029379 38049551 37489790 37969841 38759779 

            40729682 41509594 41829502