Subj : MESO: Mesoscale Discussion 2148 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Oct 15 2025 22:57:20 ACUS11 KWNS 152257 SWOMCD SPC MCD 152256=20 NEZ000-COZ000-SDZ000-WYZ000-160100- Mesoscale Discussion 2148 NWS Storm Prediction Center Norman OK 0556 PM CDT Wed Oct 15 2025 Areas affected...Northeast CO...southeast WY...western NE Panhandle...and far southwest SD Concerning...Severe potential...Watch unlikely=20 Valid 152256Z - 160100Z Probability of Watch Issuance...20 percent SUMMARY...The area is being monitored for an increase in severe-storm potential into tonight. The primary concern will be large hail, though locally severe gusts will also be possible with southward extent. The need for a watch is uncertain. DISCUSSION...The latest surface observations and visible satellite imagery indicate an east/west-oriented quasi-stationary surface boundary draped across the southwestern NE Panhandle into southeastern WY, with widespread/persistent boundary-layer stratus socked in to the north of the boundary. To the south, a mesoscale surface cyclone is evident in the Denver vicinity, with a northeastward-extending convergence zone across northeastern CO.=20 Convection has been attempting to form along the convergence zone, though weak large-scale forcing for ascent has limited convective initiation thus far. If a couple storms can evolve along the convergence zone, upper 70s to lower 80s temperatures and middle/upper 50s dewpoints will support surface-based inflow (around 1000 J/kg MLCAPE). This buoyancy and around 50 kt of effective shear will conditionally support a surface-based supercell or two, with a risk of large hail, locally severe wind gusts, and a low risk of a brief tornado (given around 200 m2/s2 effective SRH). However, overall confidence in the development of sustained surface-based storms in this corridor remains low, especially given gradually increasing nocturnal inhibition. Farther north/northwest, convection is gradually increasing along the higher terrain from north-central CO into central WY -- as midlevel heights continue falling ahead of a substantial midlevel trough moving across the Great Basin. While these storms will be moving atop a cool/stable boundary layer, around 60 kt of effective shear and steepening midlevel lapse rates will support elevated supercell structures with a risk of large hail into tonight.=20 It is unclear if the severe risk will warrant a watch issuance, though convective and environmental trends are being monitored. ...Weinman/Guyer.. 10/15/2025 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!_DMt-oXjb6K-Chi8h0uC9Krl_iSUPfAfs31_Doh2CtvTndjQSt7OnhHqN8UKB7LZFICsp10wR= Tp35mZSb78Rcbpn18w$ for graphic product... ATTN...WFO...UNR...BOU...CYS... LAT...LON 39670395 39870441 40580467 41090529 41580553 42030553 42630537 43060504 43320450 43350388 43190325 42740298 41720266 40920266 40450292 39680348 39670395=20 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 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) .