AWUS01 KWNH 141802 FFGMPD INZ000-WIZ000-ILZ000-MNZ000-IAZ000-150000- Mesoscale Precipitation Discussion 0103 NWS Weather Prediction Center College Park MD 200 PM EDT Tue Apr 14 2026 Areas affected...Eastern IA...Southern WI...Northern and Eastern IL...Western and Central IN Concerning...Heavy rainfall...Flash flooding possible Valid 141800Z - 150000Z SUMMARY...Developing and expanding clusters of heavy showers and thunderstorms coupled with locally wet/sensitive antecedent conditions will foster an isolated to scattered threat for flash flooding going through early this evening. DISCUSSION...Early afternoon GOES-E visible satellite imagery shows stronger diurnal heating promoting a steady destabilization of the boundary layer across eastern IA, western IL and nosing into southwest WI. This airmass is pooling south and east of a quasi-stationary front as multiple waves of low pressure advance along it. Some modest CINH remains in place across these areas, but MLCAPE values of 2000 to 3000 J/kg are already in place, and this is being supported by steep mid-level lapse rates transiting the Midwest. Meanwhile, satellite imagery shows a modest mid-level shortwave impulse ejecting northeastward across central and eastern IA down through northern MO and into western IL. This energy coupled with additional solar insolation should erode the remaining CAP across the region and set the stage for convective initiation. Much of this should be focused in close proximity to a leftover/diffuse outflow boundary from the early-day convection. As convection grows upscale, there will gradually be concerns for a few cell-mergers and some cell-training. A combination of multicells and supercells will be likely given the strong instability in conjunction with strong shear (effective bulk shear approaching 50 kts). The larger scale environment is also increasingly moist with aid from a southwest low-level jet of 30 to 40+ kts. Deeper layer southwesterly moisture transport is noted aloft too with elevated CIRA-LVT magnitudes. Locally significant model disagreement is noted through this evening with the placement of the convection and its general evolution, but a multi-model consensus suggests eastern IA, northern IL and southern WI seeing one focus for convection, with areas of central/eastern IL and into western IN seeing a second focus. Rainfall rates will be capable of reaching 1 to 2 inches/hour, with some localized totals by early this evening of 2 to 4 inches. The antecedent conditions are locally quite sensitive, and especially from eastern IA through northern IL and southern WI. Isolated to scattered areas of flash flooding will be possible as a result. Orrison ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...ARX...DMX...DVN...ILX...IND...IWX...LOT...MKX... ATTN...RFC...MSR...TIR...NWC... LAT...LON 43969015 43808891 43378810 42458766 41648679 41038574 40368523 39538567 39238682 39538845 40048943 41199043 41619249 41909331 42369330 42689297 43329238 43909121