Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Apr 20 2025 20:28:16 AWUS01 KWNH 202027 FFGMPD WIZ000-ILZ000-MOZ000-IAZ000-210220- Mesoscale Precipitation Discussion 0150 NWS Weather Prediction Center College Park MD 427 PM EDT Sun Apr 20 2025 Areas affected...MO into eastern IA and far western IL Concerning...Heavy rainfall...Flash flooding likely Valid 202026Z - 210220Z Summary...Heavy rain will translate north-northeast from MO into IA through 02Z with embedded rainfall rates of 1-2 in/hr due to training. Flash flooding is expected (especially across wet antecedent conditions) from an additional 2-3 inches, although 3+ cannot be completely ruled out. Discussion...20Z surface observations placed a triple point surface low along the southern KS/MO border with a cold front extending southward from the low into western AR and a warm front extending ENE across central MO. An inverted trough extended north from the triple point low through western MO into central IA with an attached surface low near CDJ. A convective line was propagating eastward ahead of the cold front through southwestern MO into a region of saturated soils due to 4 to 8 inches of rain over the past 2 days. Farther north, surface convergence along the inverted trough and slightly elevated low level convergence at the nose of 35-50 kt 925-850 mb winds were aiding the placement of a SW to NE axis of thunderstorms extending across north-central MO, with periods of training ongoing. As a potent mid-level shortwave tracks northeastward from the central KS/OK border to the east-central IA/MO border over the next 6 hours, the triple point low will follow a similar path with low level convergence sustaining thunderstorms ahead of the inverted surface trough in a SW to NE fashion (at least early on). Increasing divergent and diffluent flow aloft within the right entrance region of an upper level jet streak over western IA will overlap the low level convergence yielding strong ascent. Steering flow oriented SSW to NNE will support training along this low level convergence axis ahead of the triple point low with rainfall rates of 1-2 in/hr. Farther south, closer to the warm front's 20Z position, additional rainfall should be lighter due to the progressive nature of the convective line, with perhaps an additional 1 to 1.5 inches max over the next few hours. The greater concern for flash flooding will be over central MO due to recent heavy rain, followed by locations from northern MO into eastern IA where training is likely to produce an additional 2-3 inches along a fairly narrow axis. While a lack of recent rainfall has northern MO into southern IA with limited soil moisture values per NASA SPoRT imagery, flash flood guidance is as low as 1.5 to 2.5 inches in 3 hours and is likely to be surpassed in a few locations. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4iZwCzsOU28YRCv-ryi1RghtsXfAieEaTm8mZirYUzjFahLb77Q3yXQeIGU9Wh7IOZE-= 2YDK19ajMOGYVYxrzsOEDc0$ for graphic product... ATTN...WFO...ARX...DMX...DVN...EAX...LSX...SGF... ATTN...RFC...ABRFC...MBRFC...NCRFC...NWC... LAT...LON 42959099 41549071 39919100 38339169 37689236=20 37249332 37319402 37749442 38639448 39329435=20 40759361 42909264=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) .