Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Jun 25 2025 19:57:35 AWUS01 KWNH 251956 FFGMPD IAZ000-NEZ000-SDZ000-260155- Mesoscale Precipitation Discussion 0514 NWS Weather Prediction Center College Park MD 355 PM EDT Wed Jun 25 2025 Areas affected...Central and northeast NE, far southeast SD, and far northwest IA Concerning...Heavy rainfall...Flash flooding possible Valid 251955Z - 260155Z SUMMARY...Developing thunderstorms are expected to increase in coverage this afternoon and early evening, while also training over similar areas across central and northeast Nebraska. Hourly rainfall rates up to around 2.5" are possible as well as the potential for rainfall totals up to 4-5", which would promote possible scattered instances of flash flooding. DISCUSSION...Cooling cloudtops are evident in GOES-East infrared satelitte this afternoon as thunderstorms form along a convergent surface trough/boundary south of a frontal boundary stretching across the Upper Midwest and northern Plains. Precipitable Water values are high in the region and are estimated between 1.7-2.0", which equates to above the 90th climatological percentile according to the 00z GEFS and ECENS. Additionally, moist southerly 850mb flow of 20-25kts continues to funnel these elevated moisture values into the surface trough where thunderstorms can focus. The most important aspect of this setup is the upwind propagation vectors are parallel to this surface boundary and out of the southwest, which should promote training of thunderstorms. An instability gradient also rides along this boundary with SBCAPE values of 3000-4500 J/kg per SPC's mesoanalysis just to the south and in the inflow of these thunderstorms from south-central Nebraska to western Iowa. 18z HRRR and 12z HREF seem to be handling the convection well so far and depict the potential for hourly rates locally up to 2.5" and scattered coverage of rainfall totals over 3". Maximum amounts could approach 5" by 02Z tonight if should better training of storms materialize. This area has seen rainfall lately with MRMS analyzing an area of around 3" in central Nebraska over the last 24 hrs. 3-hr FFG is also relatively low and below 3", even as low as 1-1.5". Given the environmental setup and antecedent conditions, scattered instances of flash flooding are possible and most likely over urban regions, low-lying areas, and locations that saw heavy rain over the last 24 hrs. Snell ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6B_Y9p_f84qhpYdrtpRqh7T6PafJvwcWvHeX_CWBewcXXtiMs0LgpEqjk5fRI-qlV1cX= PHx6UX7z2-wZwDv3qqIMqr4$ for graphic product... ATTN...WFO...DMX...FSD...GID...GLD...LBF...OAX... ATTN...RFC...KRF...MSR...NWC... LAT...LON 42959656 42899532 42419492 41829571 41059727=20 40169945 40360046 41240006 42359836=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .