Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Jul 15 2025 04:17:25 AWUS01 KWNH 150415 FFGMPD MNZ000-NDZ000-151000- Mesoscale Precipitation Discussion 0691 NWS Weather Prediction Center College Park MD 1215 AM EDT Tue Jul 15 2025 Areas affected...Central/Eastern ND...Northwest MN... Concerning...Heavy rainfall...Flash flooding possible Valid 150415Z - 151000Z SUMMARY...Strong line of elevated thunderstorms favorably oriented for training; along with severe hail, should have heavy rainfall up to 1.75"/hr and may result in a narrow axis of 2-3" totals with an isolated 4" resulting in possible localized flash flooding. DISCUSSION...The area of concern in North Dakota lies in a tightly packed zonal flow pattern between two stronger waves, one exiting across SW Ontario, the upstream digging out of the Southern Canadian Rockies. To compound the situation, a strong wave in the middle stream of flow out of Wyoming Rockies was critical in driving a few QLCS complexes across the Northern Plains this evening, with the northern most surging confluent southerly to southwesterly 40-50kt 850mb flow across South Dakota. This surge had a precursory enhanced wedge of moisture that has continued to surge and pool northward along a well defined surface from from northwest MN, north of Fargo towrad JMS and BIS before sliding to the strengthening surface feature associated with the WY wave over SE MT. While northern flow tightens 850mb graident further west, the flow is generally weak across north-central/northeast ND and provides a steep isentropic boundary with solid moisture pooled along it. Total Pwats of 1.5" have been increasing due to the pre-QLCS surge and now has risen to near 1.75". Air is also quiet unstable with MUCAPE of 2000-4000 J/kg across much of NDak. As such, rapid convective developement has occured along a few west to east trending lines, with the main one from Mercer to Foster county. As noted in SPC MCD 1672, loss to hail production is likely a mitigating factor, but the strong moisture flux into such a narrow channel (particularly vertically) will support 1.5-1.75"/hr rates. The greater concern though is the deep layer steering is nearly ideally oriented to favor eventual west to east training tracks. The narrow nature to the axis may result in some misses, the axis should have 2-3" totals with a few isoalted 4" totals possible over the next 4-6hrs. This poses a localized flash flooding risk, especially near the Red River Valley where FFG values are naturally lower (if perhaps too low) but there is solid potential of exceedance along the length of the line and possible localized incidents of flash flooding overnight. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4JQX-WMUZDVI-daR9cHIPjeYNaBC25QD8zlma1CGeBthPxWX5sh2EpPWBMbiKF_jXR07= 2Sp3lC_-iZ71KcyB2_aakVI$ for graphic product... ATTN...WFO...BIS...FGF... ATTN...RFC...KRF...MSR...NWC... LAT...LON 48929501 48259463 47479475 47189514 47009626=20 46619991 46730095 47210167 47900077 48739757=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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .