Subj : MESO: Mesoscale Discussion 1801 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jul 27 2025 02:30:35 ACUS11 KWNS 270230 SWOMCD SPC MCD 270230=20 SDZ000-NDZ000-MTZ000-WYZ000-270430- Mesoscale Discussion 1801 NWS Storm Prediction Center Norman OK 0930 PM CDT Sat Jul 26 2025 Areas affected...Portions of the central Dakotas and far southeast Montana Concerning...Severe Thunderstorm Watch 546... Valid 270230Z - 270430Z The severe weather threat for Severe Thunderstorm Watch 546 continues. SUMMARY...Several localized corridors of heightened severe weather potential are emerging across the central Dakotas and far southeast Montana. DISCUSSION...A complex convective situation continues to unfold across the Dakotas with several areas of localized concern beginning to emerge. Along the ND/SD border, explosive updraft development is noted in GOES imagery. This convection is developing within an extremely, and thus far untapped, air mass with MLCAPE estimates of around 4000 J/kg and mid-level lapse rates on the order of 9 C/km (per regional 00z RAOBs). This new convection will likely develop into one or more organized supercells given adequate deep-layer wind shear (around 30-40 knots per regional soundings) with an attendant threat for large to very large (1.5-2.75 inch) hail and severe gusts. RAP mesoanalysis estimates also characterize the environment with STP values between 3-5, and while these values are likely being driven by extreme buoyancy, some low-level veering is noted within the 0-2 km layer per the KABR VWP, suggesting at least some localized tornado threat.=20 To the south, a cluster of supercells is beginning to grow upscale. KABR velocity imagery shows an uptick in low-level outflow as this transition occurs, suggesting severe winds may become the primary hazard over the next hour or two.=20 Along the MT/SD border, several supercells are noted in regional radar imagery, and storm spacing appears sufficient to maintain the storm mode for the near-term (next hour or so). As such, the primary hazard should remain large hail, though additional updraft development is noted in GOES imagery across southeast MT, suggesting that upscale growth is still probable over the next few hours as this activity spreads northeast into the Dakotas. As this occurs, the potential for severe winds should increase. ...Moore.. 07/27/2025 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!6Jr0K56jbFB8Z2L7xBkArGd2nfRLvXXjECIN8NIUR4bUqJDQRctplym39_9Q8thR_norkrzg5= rruqldhBn2TMAO4ZiA$ for graphic product... ATTN...WFO...ABR...BIS...UNR...BYZ... LAT...LON 44860421 45000465 45240493 45590495 45850481 46000447 46620097 46679973 46539917 46209887 45779869 45419870 44929878 44639925 44529998 44740381 44860421=20 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN =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) .