Subj : MESO: Mesoscale Discussion 1253 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jun 25 2023 17:06:17 ACUS11 KWNS 251706 SWOMCD SPC MCD 251705=20 ARZ000-OKZ000-251830- Mesoscale Discussion 1253 NWS Storm Prediction Center Norman OK 1205 PM CDT Sun Jun 25 2023 Areas affected...portions of eastern Oklahoma into western Arkansas Concerning...Severe potential...Severe Thunderstorm Watch likely=20 Valid 251705Z - 251830Z Probability of Watch Issuance...95 percent SUMMARY...The severe threat is increasing across portions of eastern OK into western AR. Severe hail and wind are the main threats, with 2+ inch diameter stones and 65+ kt gusts possible. A Severe Thunderstorm Watch issuance will be needed. DISCUSSION...Clear skies have allowed for mixing and destabilization of the boundary layer ahead of the surface cold front across eastern portions of OK into west-northwest AR. Visible satellite indicates increasing cumulus ahead of the surface cold front, with mesoanalysis showing convective inhibition gradually eroding across eastern OK/western AR. Convective initiation may occur sooner than what the more recent CAM guidance suggested. Surface temperatures are warming into the 90s F, that combined with mid 70s F dewpoints overspread by 7.5+ C/km mid-level lapse rates, is contributing to over 4000 J/kg of SBCAPE/MUCAPE. Furthermore, gradual veering winds in the surface-700 mb layer, and unidirectional speed shear above 700 mb, are supporting modestly curved but elongated hodographs over the warm sector, with effective bulk shear exceeding 40 kts in some locales.=20 The current thinking is that rapid, intense multicellular or transient supercellular development is likely in the next few hours, with large hail (some 2+ inches) the main concern initially. After a couple of hours, rapid upscale growth via merging cold pools should support the development of an intense MCS/possible southeastward propagating bow echo. While severe hail cannot be ruled out with this mode of convection, severe winds should become the dominant concern, with 65+ kt gusts possible. A Severe Thunderstorm Watch will be needed within the next 1-2 hours to address the impending severe threat. ...Squitieri/Grams.. 06/25/2023 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!7_e2GlALuSRJwF63VFCFPUTFNJt5IAgdYuP77l9N9XvpyvaVg6OkDlmgml47ukVOg0Fbyoyww= 4pd_nnLb7IMFHHXnjA$ for graphic product... ATTN...WFO...MEG...LZK...SHV...TSA... LAT...LON 34259514 34559563 35039586 35489579 35969482 36189300 36249148 36129084 35899051 35389041 34869076 34429200 34199348 34259514=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .