AWUS01 KWNH 261550

FFGMPD

WIZ000-MNZ000-IAZ000-NEZ000-262130-



Mesoscale Precipitation Discussion 0519

NWS Weather Prediction Center College Park MD

1149 AM EDT Thu Jun 26 2025



Areas affected...Northern & Western IA...Southern MN...Far Eastern

NEB...Far Southwest WI...



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



Valid 261550Z - 262130Z



SUMMARY...Widely scattered elevated convection with some repeating

elements will increase in coverage/surface rooting throughout the

afternoon with 1.5-2"/hr rates and streaks of 2-3.5" totals over

sensitive solids suggesting possible incidents of flash flooding

by 21z.



DISCUSSION...15z Surface analysis shows main surface low near

Norfolk, NEB with well defined cold front dragging southwest into

north-central KS east of Hill City; while downstream a pre-frontal

pressure trof, generally along the core of the deeper layer

moisture axis/warm conveyor belt extends from another weak low

near CKP through Omaha/Council Bluffs into northeast KS and is

well noted by alto-stratus deck with some isolated weaker

convective cores where sfc to boundary layer convergence is

maximized across western IA.  East of that, clear skies in the

warm sector extend to the surface front being strongly reinforced

through differential heating with extensive low-stratus deck along

the eastern MN/IA border into the Driftless area of SW WI. 

SBCAPEs are rising into the upper 3000s J/kg across the clearing,

though solid southerly WAA/ moisture flux along the pressure trof

of 35-40kts, isentropic ascent is starting to increase elevated

convective development along and downstream of the DPVA from the

upper-level trough.  Combine this with highly favorable right

entrance ascent/divergence across NW IA into south-central MN,

convection will continue to develop/expand over the next few

hours.  



Orientation of the frontal zone to the mean motion of the

shortwave combined with the steepened isentropes further east,

ascent pattern across north-central IA/southern-MN should see

greatest convective development with stronger/broader updrafts. 

Combined with increasing flux convergence, efficient rainfall

production will support rates of 1.5-2"/hr fairly quickly in the

life-cycle.  Additionally, the convergence axis will be broad and

fairly parallel to the boundary and deeper layer flow to support

some repeating cell motions/tracks.  This will be key toward

increased overall rainfall totals nearing 3-3.5" locally given

individual cell motions may limit heavy rainfall duration to those

1.5-2" hourly totals. 



Hydrologically, the area remains very saturated with much of IA

and southern MN having 0-40cm relative soil moisture ratios within

the 60-70% range, generally well into the 90th+ percentiles

helping to have confidence that hourly FFG values of 1-1.5" and

3hr at 1.5-2" within the area of concern.  Combine this with the

narrow axis of training cells from last night from Colfax/Dodge,

NEB to Ida/Sac to Humbolt/Wright in IA and Fillmore, MN/Howard, IA

 further compromising upper-soil uptake.  Scattered incidents of

flash flooding will become increasingly likely toward 21z across

the MPD area.



Gallina



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



ATTN...WFO...ARX...DMX...FSD...MPX...OAX...



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



LAT...LON   44909147 44539068 43729072 43139170 42659272 

            41149501 40889599 41289672 41919666 42409646 

            43649553 44249460 44879298 

