Subj : MESO: Mesoscale Discussion 0644 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Apr 27 2023 23:58:15 ACUS11 KWNS 272358 SWOMCD SPC MCD 272357=20 ALZ000-MSZ000-TNZ000-ARZ000-280200- Mesoscale Discussion 0644 NWS Storm Prediction Center Norman OK 0657 PM CDT Thu Apr 27 2023 Areas affected...Eastern Arkansas to northern Mississippi and northwest Alabama Concerning...Severe Thunderstorm Watch 176... Valid 272357Z - 280200Z The severe weather threat for Severe Thunderstorm Watch 176 continues. SUMMARY...The threat for severe hail and damaging winds continues across much of WW 176, but the greatest near-term risk will reside across eastern Arkansas into northwest Mississippi and far eastern Mississippi to far west/northwest Alabama. DISCUSSION...Scattered convection continues to erupt immediately ahead of a mid-level vorticity maximum traversing across central AR. This zone of focused ascent, combined with a favorable thermodynamic and kinematic environment, has supported splitting supercells, including a more prominent/robust cell across Arkansas/Monroe counties that has remained relatively isolated. These cells will continue to pose a large hail threat for the next 1-2 hours as they move towards the apex of the MLCAPE axis across northwest MS. However, long-term trends are somewhat uncertain given consolidating convection along an outflow boundary to the west of the more discrete activity, and the propensity for storm interactions/amalgamating outflows with time within the focused zone of ascent. Such upscale growth may favor an increasing damaging wind threat, but weak low-level shear (around 20-25 knots in the 0-3 km layer) sampled by regional VWPs casts uncertainty onto this scenario. To the east along the MS/AL border, a pair of long-lived supercells with a history of 1-1.75 inch hail will begin to gradually meander into the periphery of the higher mixed-layer buoyancy as they migrate into western AL. However, the isolated nature of the convection combined with 40-45 knots of effective bulk shear downstream should help maintain storm intensity and the associated large hail threat for the next few hours. Elsewhere across WW 176, environmental parameters remain conducive for organized convection, but additional CI is uncertain. The most likely location for near-term CI appears to be across northwest MS where the GOES day cloud phase RGB and low-level water vapor imagery shows shallow convective towers, but robust convective initiation remains uncertain given the onset of diurnal cooling. ...Moore.. 04/27/2023 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!8J18pgR2QNqaIua5SmpdeqydFUR_oBckpQI1Jdwy_Xw7PhiqphzBUxzUWMOb4IxGcOHLaOcBV= kwKnhourKVrxCae4qI$ for graphic product... ATTN...WFO...BMX...HUN...MOB...MEG...JAN...LZK... LAT...LON 33429120 33699189 34499215 35239203 35569137 35669044 35428916 34868835 34138728 33878712 33548705 33138722 32758762 32398807 32158870 32248922 32498947 33429120=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) .