Subj : MESO: Mesoscale Discussion 1978 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Nov 29 2022 17:21:36 ACUS11 KWNS 291721 SWOMCD SPC MCD 291720=20 MSZ000-ARZ000-LAZ000-291945- Mesoscale Discussion 1978 NWS Storm Prediction Center Norman OK 1120 AM CST Tue Nov 29 2022 Areas affected...northern LA...extreme southeast Arkansas and into central MS Concerning...Severe potential...Tornado Watch likely=20 Valid 291720Z - 291945Z Probability of Watch Issuance...95 percent SUMMARY...A PDS tornado watch will be needed by 19z/1pm CT for portions of northern Louisiana, extreme southeast Arkansas and into central Mississippi. Tornadoes, a couple potentially long-track and strong, large hail and damaging gusts will be possible into the evening hours. DISCUSSION...Rich Gulf boundary-layer moisture continues to rapidly return northward across the Lower MS Valley vicinity. Surface dewpoints near 65 F have developed as far north as south-central MS and northern LA late this morning. Meanwhile, the marine warm front, roughly delineating 70 F dewpoints, extends west-to east from southeast TX through central LA into southern MS. Moisture should continue to rapidly increase across northern LA into far southeast AR and MS through the afternoon. A plume of steep midlevel lapse rates will continue to overspread the region, aiding in MLCAPE increasing to 1000-2000 J/kg by mid-afternoon. Breaks in cloud cover across northeast LA into central MS will further aid in destabilization as greater heating occurs within these cloud breaks. Strong vertical shear, with effective shear magnitudes greater than 45 kt is already in place across the region. Regional VWPs and profilers already show enlarged, favorably curved low-level hodographs with 0-1 km SRH values greater than 250 m2/s. Large-scale ascent will remain modest across the region, resulting in a large warm sector supporting discrete supercells. One or more bands of supercells will be possible within low-level confluence zones.=20 A particular dangerous situation is expected to develop across northeast LA into central MS through this evening as multiple supercells track across the area. Tornadoes, a couple strong and long-track, will be possible, in addition to large hail (scattered 2+ inch) and damaging gusts. ...Leitman/Hart.. 11/29/2022 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!55HEScaA-wGCzsT1Ygo2AoWdOVWeh87dfehKhDcTvd7iD3mm_YMWVOAc4t5pGcDPZDW83Nf9U= 9BrVcXv5_B044bB2S0$ for graphic product... ATTN...WFO...MEG...JAN...LZK...LCH...SHV... LAT...LON 31979322 32349307 32839272 33529153 33769082 33869032 33888967 33648891 33408865 32828846 32448861 32038886 31728928 31628956 31509045 31369186 31379278 31599318 31979322=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) .