Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue May 30 2023 06:27:03 AWUS01 KWNH 300626 FFGMPD MNZ000-IAZ000-SDZ000-301020- Mesoscale Precipitation Discussion 0385 NWS Weather Prediction Center College Park MD 226 AM EDT Tue May 30 2023 Areas affected...eastern SD into southwestern MN and far northwestern IA Concerning...Heavy rainfall...Flash flooding possible Valid 300622Z - 301020Z SUMMARY...Southwest to northeast training of heavy rain may produce localized flash flooding across eastern SD into southwestern MN through 10Z. Peak rainfall rates of 1-2 in/hr are expected. DISCUSSION...Surface observations from 06Z showed an axis of convergence in eastern SD, extending southeastward along the NE/IA border, associated with a stationary front. Scattered thunderstorms were occurring to the east of the stationary front and north of a mesoscale outflow boundary arcing southwestward from eastern Murray County into eastern SD, just north of FSD. RAP analysis soundings over eastern SD and southwestern MN suggest that the storms were elevated, rooted between 750-700 mb, working with weak CAPE near 500 J/kg and PWATs of 1.2-1.4 inches. The 06Z SPC mesoanalysis supported MUCAPE as high as 1000 J/kg farther south near FSD but less than 100 J/kg into the eastern half of MN. The VAD wind profile from KFSD showed 850-700 mb winds from the southwest at 30-35 kt, overrunning the stationary front with radar reflectivity showing localized areas of training, such as within Rock County in southwestern MN with MRMS rainfall estimates of 1 to just over 2 inches in the hour ending 06Z. The overrunning flow regime should continue over the next few hours but with upper forcing tied to a shortwave trough...extending from the eastern Dakotas into east-central NE...expected to track eastward, the focus for heavier rain should end from west to east. Until then however, periods of localized training could support rainfall rates of 1-2 in/hr with localized totals of 2-3 inches across portions of far eastern SD, southwestern MN and perhaps northwestern IA prior to 10Z. Current thinking is that The axis of best moisture/forcing and heaviest rain should translate from west to east over the next few hours, eventually moving into a region with reduced instability and effectively ending the flash flood threat by 10-11Z. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9LvLRU_FFMaoIeKQYggJa7Qb4CIfMg9cGOBbry_Nd3Ddc_RFEcNbjbF04wg18cC2jOWp= KjMwOgpaXN23EXbNMKilWco$ for graphic product... ATTN...WFO...ABR...DMX...FGF...FSD...MPX... ATTN...RFC...MBRFC...NCRFC...NWC... LAT...LON 45849568 45459471 44599400 43389355 42949439=20 42999629 43879691 44899713 45719669=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .