Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jun 19 2025 18:27:51 AWUS01 KWNH 191826 FFGMPD MSZ000-LAZ000-ARZ000-200000- Mesoscale Precipitation Discussion 0485 NWS Weather Prediction Center College Park MD 226 PM EDT Thu Jun 19 2025 Areas affected...Central Arkasas...West-central Mississippi...Far Northern Louisiana... Concerning...Heavy rainfall...Flash flooding possible Valid 191830Z - 200000Z SUMMARY...Delicate balance of weak inflow and convergence to maintain thunderstorms in a favorable slow/repeating steering environment. Fairly saturated upper-soils may result in increased runoff and possible localized incident(s) of flash flooding. DISCUSSION...Regional RADAR mosaic depicts the main core of the outflow boundary from this morning's MCS continue to accelerate southward across eastern MS/western AL as the core of the cold pool presses south-southeastward starting to break out new convection along its leading edge. Upstream, however, the affects of the cold pool are much less as the overall larger scale forcing/shortwave slides northeast across the upper-TN Valley.=20 Yet, the tail end of the cold front is hanging around with weak northwesterly flow and drier air helping to tighten the theta-E gradient across E OK into central AR. Temperatures are nearing 90F whil Tds are in the mid to upper 70s, with ample pooled 850-700mb moisture noted in CIRA LPW along the intersection of the outflow boundary to the cold front along the MS River. CIRA LPW=20 does note that mid-level drying has mixed in across the region and the combination of slightly steeper lapse rates in this region has bumped up MLCAPEs to 3000-3500 J/kg.=20=20 The key will be prolonged/sufficient low level inflow/convergence to maintain convective development. Currently, VWP at LZK/SHV and boundary layer cu tracers suggest 15-20kts of confluent/convergence across central AR to help spark the initial convective development. RAP analysis of bulk shear suggests proximity of the mid-level flow is sufficient for 20-25kts to maintain weak organization and while right entrance divergence is best maximized downstream across the convective cores east of the MS River, there should be enough tilt to allow for a few updraft cycles.=20 As noted, total PWat values are AoA 2" with the weak inflow suggest solid moisture loading for 1.75-2"/hr rates, but updrafts may still be fairly narrow. However, with expected 10-15kts of upstream confluence flow into the boundary layer, convergence on outflows and deep layer steering along/just southeast of the frontal zone should allow for some repeating/training potential. Allowing for 2-3" localized totals. While FFG seems to have rebounded to normal/average values, the upper-soils remain fairly saturated at over 60% per NASA SPoRT LIS products which are well into the 90th percentile. This suggests, given the intensity of the rates, reduced infiltration and increased runoff potential.=20 If the updrafts are broad enough, localized flash flooding is considered possible through the afternoon.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!73t4Php53iecAKRRi2iXTQBbsAIsJM_fLLQ2To9HVyuGtWM9kPQLPyAoyt_XpTnFFDxU= tI_NVvC2cfP_fD4ug76ZmWw$ for graphic product... ATTN...WFO...JAN...LZK...SHV... ATTN...RFC...ORN...TUA...NWC... LAT...LON 35059363 34839237 34409167 33469014 32818991=20 32369058 33149241 33649331 34309422 34829424=20 =20=20=20=20=20=20=20=20=20=20=20=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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .