Subj : MESO: Mesoscale Discussion 0851 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun May 18 2025 08:20:38 ACUS11 KWNS 180816 SWOMCD SPC MCD 180815=20 ARZ000-OKZ000-180915- Mesoscale Discussion 0851 NWS Storm Prediction Center Norman OK 0315 AM CDT Sun May 18 2025 Areas affected...central/eastern Oklahoma into western Arkansas Concerning...Severe Thunderstorm Watch 283... Valid 180815Z - 180915Z The severe weather threat for Severe Thunderstorm Watch 283 continues. SUMMARY...Organized cluster of thunderstorms will continue to pose a threat of large hail and damaging winds. An extension in time for Severe Thunderstorm Watch #283 will be needed. DISCUSSION...A linear MCS has organized across central Oklahoma this morning and will continue to move east/east-southeast along an instability axis stretching from northwest Oklahoma into southeast Arkansas. To the south of this axis, rich low-level moisture couples with steep mid-level lapse rates to yield MUCAPE in excess of 3500 J/kg. Effective-layer shear is generally greater than 45-50 knots, which is more than sufficient to maintain updraft organization. In fact, recently the Oklahoma Mesonet station in Okmulgee, OK, measured a 60 mph wind gust. This MCS is currently contained within Severe Thunderstorm Watch #283, which is set to expire at the top of the hour (0900 UTC / 0400 AM CT). Given that the overall environment remains supportive of organized severe weather, and the existing organized MCS, within this environment, the threat for large hail and damaging winds will likely continue past the original expiration time of 0900 UTC (4 AM CT). As such, a local extension in space and time (to 1200 UTC / 7 AM CT) has been coordinated with WFO TSA. ...Marsh.. 05/18/2025 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!6gLR_CCj9KCAitpWS1IILSvk4HR14wb8rooRwvuHbmY6UXt1d0iFpNqJZDiRc_rlrXgai0fi6= tsN_Md5xP7t3D-5KSg$ for graphic product... ATTN...WFO...TSA...OUN... LAT...LON 35179666 36179574 36109350 34649473 35179666=20 MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH MOST PROBABLE PEAK WIND GUST...65-80 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .