Subj : MESO: Mesoscale Discussion 1151 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jun 18 2023 20:13:24 ACUS11 KWNS 182013 SWOMCD SPC MCD 182012=20 LAZ000-ARZ000-TXZ000-OKZ000-182145- Mesoscale Discussion 1151 NWS Storm Prediction Center Norman OK 0312 PM CDT Sun Jun 18 2023 Areas affected...portions of northeastern Texas into northwestern Louisiana Concerning...Severe potential...Watch possible=20 Valid 182012Z - 182145Z Probability of Watch Issuance...40 percent SUMMARY...Trends are being monitored for the possibility of thunderstorm development over the next few hours. The severe threat is highly conditional on storm development. Should storms develop, severe hail/wind will be possible and a tornado cannot be ruled out. DISCUSSION...Insolation following earlier storms has allowed for ample surface heating and associated modification of the boundary layer around/just south of the Arklatex. Some slightly agitated cumulus have recently become apparent ahead of a southward sagging boundary, which also intersects another outflow boundary left behind by earlier storms. Surface temperatures reaching 90 F amid 75+ F dewpoints, overspread by 8.5 C/km mid-level lapse rates, is contributing up to 4500 J/kg MLCAPE. While some billow clouds are evident via visible satellite, the agitation of cumulus also suggests that remaining convective inhibition/boundary-layer stabilization continues to erode. The presence of a 30 kt southwesterly low-level jet, overspread by 50+ kts of west-northwesterly 500 mb flow, is also supporting modestly curved, elongated hodographs bearing 50+ kts of effective bulk shear across the warm sector. As such, supercells would likely be the primary mode of convection, with any storm mergers supporting southeastward-propagating bow-echo MCSs. The ambient environment clearly supports the potential for significant severe storms, including very large hail and perhaps a tornado with supercells, and severe gusts with bowing structures. However, relatively neutral height falls introduces uncertainty of convective initiation, with high-resolution model guidance demonstrating little consensus for a given solution. Nonetheless, convective trends will continue to be monitored and a WW issuance may be needed if clearer signals of thunderstorm development become apparent. ...Squitieri/Hart.. 06/18/2023 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!9A0HsY5MWb0V1I7gbSnVjCB8A49cHhpkCA5YkXVWcwH9IIL5qBkULKb2zGx-dmO4SyzYknRdA= HB5ApDdlRFwpYK2gCM$ for graphic product... ATTN...WFO...SHV...HGX...FWD... LAT...LON 31589669 31929710 32419717 33169639 33749525 33889444 33709410 33349387 32769367 32069358 31749378 31529432 31369515 31319577 31369619 31589669=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) .