Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jun 26 2023 08:50:46 AWUS01 KWNH 260850 FFGMPD LAZ000-ARZ000-TXZ000-OKZ000-261349- Mesoscale Precipitation Discussion 0587 NWS Weather Prediction Center College Park MD 449 AM EDT Mon Jun 26 2023 Areas affected...southwestern/southern Arkansas, southeastern Oklahoma, northern Lousiana, far northeastern Texas Concerning...Heavy rainfall...Flash flooding possible Valid 260849Z - 261349Z Summary...Backbuilding and training convection continues to produce heavy rainfall at times particularly in southwestern Arkansas near Murfreesboro. Flash flooding remains possible especially in areas of prolonged (1+ hour) heavy rainfall. Discussion...The presence of weak low-level confluence along an axis extending from near Mena to Monticello, AR and a weak mid-level shortwave trough over Oklahoma continues to foster robust convective development across southwestern Arkansas this morning. Just south/west of the confluence axis, strong instability (3500 J/kg MLCAPE) - bolstered by near 80F dewpoints - continued to foster the convection and resultant heavy rainfall rates. Meanwhile, the axis of convergence was parallel to steering flow aloft, allowing for continued northwest-to-southeast movement and areas of training convection. One linear segment near Union County, AR was forward propagating, but upstream convection was translating very little off of its current axis, resulting in persistent 1-1.5 inch/hr rain rates and 3-hour totals from 2-4.5 inches (per MRMS). Low to moderate MRMS Flash responses were also noted beneath the the convective band also, suggesting the presence of excessive runoff. The potential for continued flash flooding is a bit uncertain this morning. Although persistent rainfall continues from Mena to Monticello with very little translation off that axis, storms this morning have tended to grow upscale and shift slowly southward with time. FFGs south of the ongoing band are in the 3-4 inch/hr range, suggesting that at least 1 hour of heavier rain rates would be needed to heighten concerns. Thus, flash flood potential is highly dependent on local cold pool evolution, any resultant propagation, and persistence of convection through 13Z. At least a low-end flash flood risk will exist across the discussion area this morning. An eventual southward shift of a synoptic cold front into the region may shift heavier rainfall axis, although this process could take a few hours to materialize. Cook ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_1wFD1RzNhE_G_K4bB_480aM38_YPKLrdEXN67xXH-kL2E62ljvs8VmSgJKU5dt0r7jx= jfvWHrAtkvFEDY7mSJFwtMw$ for graphic product... ATTN...WFO...FWD...JAN...LZK...OUN...SHV...TSA... ATTN...RFC...ABRFC...LMRFC...NWC... LAT...LON 34869462 34519292 33899190 33029175 32439207=20 32349294 32949399 33869533 34799602=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) .