Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jun 21 2025 02:03:51 AWUS01 KWNH 210202 FFGMPD MIZ000-WIZ000-MNZ000-NDZ000-210800- Mesoscale Precipitation Discussion 0488 NWS Weather Prediction Center College Park MD 1001 PM EDT Fri Jun 20 2025 Areas affected...eastern North Dakota, northern Minnesota, northwestern Wisconsin Concerning...Heavy rainfall...Flash flooding possible Valid 210200Z - 210800Z Summary...Convection is expected to rapidly deepen and expand in coverage across the discussion area in the 03-08Z (10p-3a CDT) timeframe. These storms will exhibit mergers and localized training, with a risk of 2 inch/hr rain rates and a few areas of flash flooding. Discussion...Intense, deep convection has begun to quickly forward propagate eastward across southwestern South Dakota. Meanwhile, isolated cells have formed on the nose of strengthening low-level flow across eastern South Dakota, with supercellular structures noted near Jamestown, ND. These storms are exhibiting a limited flash flood risk at the moment, with fast storm motions across western North Dakota and isolated storm coverage in eastern North Dakota both limiting the spatial extent of any heavy rainfall. A few spots of 2 inch/hr rain rates near Jamestown could prompt isolated flash flood issues in the short term. Over time (more likely after 03Z/10p CDT), increasing low-level flow across the eastern Dakotas and strong speed convergence along the nose of that low-level flow across northern Minnesota will combine with strong instability (1500-4000 J/kg MLCAPE) to produce widespread thunderstorm activity. These storms should eventually concentrate along an axis from near/north of Fargo to ner Duluth.=20 They'll also form in close enough proximity to promote occasional mergers and localized training, with spots of 2 inch/hr rain rates expected at times. Additionally, storms should eventually merge with upstream convection across North Dakota, providing further opportunity for prolonging of heavy rain rates at any one spot.=20 Widespread 1-3 inch rainfall totals are expected beneath the convection, with local amounts of 5 inches possible where training/mergers are most pronounced. These rates will fall on areas of 1-2 inch/hr FFG thresholds (lowest along the ND/MN border and across northeastern Minnesota), with exceedence expected at times. Flash flooding is possible in this scenario. Cook ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-Jy1OECamoSmfT4u0aW2Hzlx6jsyMA6UbK8afi-2qJMbkOjaMRnxQSJyh3fZX4dABMPr= 6Xnz7xYxQZmnqwjag3tXK5Q$ for graphic product... ATTN...WFO...BIS...DLH...FGF...GRB...MPX...MQT... ATTN...RFC...KRF...MSR...NWC... LAT...LON 48909458 48399232 47819106 47079065 45809004=20 45429061 45729145 46589408 46639663 46399986=20 46820093 47540036 47839969 48409860 48889700=20 =20=20=20=20=20=20=20=20=20=20=20=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) .