Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Aug 08 2025 06:47:13 AWUS01 KWNH 080646 FFGMPD MNZ000-NDZ000-081200- Mesoscale Precipitation Discussion 0882 NWS Weather Prediction Center College Park MD 245 AM EDT Fri Aug 08 2025 Areas affected...North Dakota into far western Minnesota Concerning...Heavy rainfall...Flash flooding possible Valid 080644Z - 081200Z Summary...A strong MCS moving across North Dakota will continue to race eastward through the morning. Despite the fast motion, rainfall rates in excess of 2"/hr may exhibit short-term training to produce 2-3" of rain and isolated instances of flash flooding. Discussion...The regional radar mosaic early this morning shows a powerful MCS moving across central North Dakota. On the north side of this linear MCS, a strong MCV has developed which is clearly evident on radar. This MCS is being driven by a convectively enhanced shortwave embedded within pinched flow downstream of a pronounced trough diving across the Northern Rockies. Downstream of this feature, the environment is extremely supportive of strong convection with heavy rainfall. Recent GPS measured PWs are as high as 1.4 inches in western MN, and analyzed via the SPC RAP to be as high as 1.6 inches in eastern ND, which are both above the 90th percentile for the date. Additionally, MUCAPE immediately downstream of this MCS is as high as 4000 J/kg, which when combined with the anomalous PWs will continue to support the progression of this MCS and its radar-estimated rain rates which are above 1.5"/hr according to KMBX. 850mb inflow within the LLJ has been measured recently via local VWPs to be above 25 kts from the south, which is helping to resupply the most favorable thermodynamics into this pre-convective environment. Although this will gradually veer during the next several hours, a brief period of backing and acceleration immediately downstream of the MCS and its accompanying MCV will help briefly intensify rain rates on the leading edge of the system. Both HREF and REFS probabilities for 2"/hr rainfall rates peak at 15-20% in the next few hours, although brief rain rates as suggested by recent HRRR and WoFS runs could exceed 4"/hr. While this system should remain generally progressive, as the LLJ begins to veer in the next few hours, some short term training, especially along the SW flank, could occur. Additionally, some enhanced convergence behind the leading squall line could result in secondary development of prolonged rainfall, although with lesser intensity than previously. However, where any training can occur, especially in the vicinity of the most intense rainfall rates, the HREF indicates a 20-30% chance of at least 3" of rain accumulation, such that any additional rainfall towards morning behind the squall line could enhance the flash flood risk. The general threat appears to primarily be isolated, but a few locations across eastern ND have been quite wet recently, leading to compromised FFG. So, if any of this training were to occur across the more sensitive soils or urban areas, a few instances of flash flooding could occur. Weiss ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-chXPVmovtxX3yjfLRnxqsxEnOkYvxoM1dUHoCyMn4zqnO22WJAOgY9WtWF4E6QTD6kt= X1IveVVAC5AercdB1x-oaQ8$ for graphic product... ATTN...WFO...BIS...FGF... ATTN...RFC...KRF...MSR...NWC... LAT...LON 49139689 48849551 48479492 48079483 47659506=20 47189551 46739617 46399719 46359735 46449834=20 46549930 46490021 46320103 46320166 46520214=20 47120190 47800116 48729966 49109799=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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .