Subj : MESO: Mesoscale Discussion 1923 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Aug 09 2023 23:11:13 ACUS11 KWNS 092311 SWOMCD SPC MCD 092310=20 MOZ000-ARZ000-OKZ000-100115- Mesoscale Discussion 1923 NWS Storm Prediction Center Norman OK 0610 PM CDT Wed Aug 09 2023 Areas affected...Eastern Oklahoma...northwest Arkansas...and southwest Missouri Concerning...Tornado Watch 618... Valid 092310Z - 100115Z The severe weather threat for Tornado Watch 618 continues. SUMMARY...The threat for all severe hazards continues across WW 618. The severe threat will be greatest in the near-term across southwest Missouri where storms continue to mature, but destabilization across western Arkansas is increasing the potential for severe storms later this evening. DISCUSSION...Convective clusters continue to mature across southwest MO into far northeast OK. This activity has remained fairly benign so far, likely due to unfavorable deep-layer shear and storm motion orientations relative to the initiating boundary that are fostering storm interactions and upscale growth. However, MRMS vertically integrated ice and lightning trends have shown steady, though gradual, intensification. Further upscale growth into a semi-organized line appears probable in the coming hours, but any discrete cells that can become established just ahead of the line will pose a tornado risk if they can achieve east/southeast storm motions (which will maximize low-level SRH). Lingering inhibition downstream is apparent in visible imagery in the form of billow clouds along the AR/MO border. Consequently, the threat for severe wind/hail (and perhaps a tornado) will be limited to southwest MO for the next hour or so where temperatures are warming into the upper 70s/low 80s. Further south across eastern OK to western AR, surface temperatures continue to climb into the low/mid 80s amid broken cloud cover. Recent forecast soundings suggest that temperatures in the mid-80s are required to erode lingering inhibition and support surface-based convective initiation. These temperatures are currently being observed on the western fringe of WW 618 over central to eastern OK where a few attempts at convective initiation have been observed over the past 30 minutes in visible imagery. While forcing for ascent over this region has been meager up to this point, the approach of the upper trough from the west should increase the probability of convective initiation within the next couple of hours. Strong low-level shear is noted on the KSRX VWP where easterly winds through the AR River Valley are supporting 0-1 km SRH values around 350 m2/s2. This shear will likely diminish somewhat as boundary-layer mixing increases amid continued warming, but the combination of strong deep-layer shear, favorable low-level SRH, and increasing buoyancy will support severe convection capable of all hazards through heading into the evening hours. ...Moore.. 08/09/2023 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!7dIpH9W-dbIm4iIVltkOvFCPFC4N8zjNBM2U1NaZfB5IAr29gDVxDT0SkPM13MenP01WGqf-9= NQfEZtbnZXU9KooqQw$ for graphic product... ATTN...WFO...LZK...SGF...TSA... LAT...LON 34879443 34829481 35259576 35719578 36729468 37309367 37349284 37149224 36909212 36539224 35459343 34879443=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) .