Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jun 26 2025 01:46:52 AWUS01 KWNH 260145 FFGMPD IAZ000-KSZ000-NEZ000-SDZ000-260745- Mesoscale Precipitation Discussion 0517 NWS Weather Prediction Center College Park MD 944 PM EDT Wed Jun 25 2025 Areas affected...Much of central and eastern Nebraska, far northern Kansas, and western Iowa Concerning...Heavy rainfall...Flash flooding likely Valid 260145Z - 260745Z SUMMARY...Ongoing thunderstorm activity combined with renewed convection tonight associated with an approaching upper shortwave trough is expected to continue the threat for scattered flash flooding. Additional rainfall totals in excess of 3" appear likely in spots, which should spawn new and renewed scattered instances of flash flooding across already saturated parts of central Nebraska into western Iowa. DISCUSSION...Overall setup remains similar to this afternoon and early evening with a well-defined outflow boundary depicted by GOES-EAST IR satellite imagery stretching from central Iowa into southern Nebraska, focusing convection overruning to the north while progressing northeastward. Meanwhile, an approaching upper shortwave over the central/northern High Plains is responsible for scattered convection currently over western Nebraska and eastern Colorado. This activity is expected to enter central Nebraska by about 04Z or so along with scattered thunderstorms maintaining along the instability gradient associated with the aforementioned outflow boundary. PWs remain elevated and in the 1.6-2.1" range (well above climatology), along with MLCAPE values of 1000-2000 J/kg. Meanwhile, mid-level southerly flow also remains modest around 25-30 kts and should increase with time in response to the approaching shortwave and nocturnal low level jet. This should aid in isentropic ascent and greater coverage of intense rainfall rates. Latest HRRR, HREF, and experimental RRFS/REFS are all in line the potential for an additional 3" of rain over areas that have received 2-4" of rainfall over the last 24 hours per MRMS. FFG in this region depicts many areas with 3-hrly values under 2" and the 18z HREF has a stripe of 30-60 percent exceedence probabilities (although probably displaced a bit too far to the north given the latest southerly trends and sinking outflow boundary). For this reason, additional scattered flash flooding tonight is deemed likely. Snell ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5q5aAHo5jtn0N35EVSziHMQXrr0MRrchagREUGdhs1Fkohxze_y7_Bk9lay9jrgn3Waq= oO5Lw8Yln8NkX_2reUX8z0U$ for graphic product... ATTN...WFO...DMX...FSD...GID...GLD...LBF...OAX... ATTN...RFC...KRF...NWC... LAT...LON 42549705 42549530 41529504 40359693 39799887=20 39800057 40320153 41250136 42019923=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) .