Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jun 26 2023 01:49:24 AWUS01 KWNH 260149 FFGMPD ARZ000-OKZ000-260730- Mesoscale Precipitation Discussion 0583 NWS Weather Prediction Center College Park MD 948 PM EDT Sun Jun 25 2023 Areas affected...far eastern OK into central/southern AR Concerning...Heavy rainfall...Flash flooding possible Valid 260147Z - 260730Z SUMMARY...The potential for training thunderstorms over far eastern OK into central/southern AR may produce localized flash flooding overnight. Rainfall rates of 2-3 in/hr will be possible through 07Z. DISCUSSION...Regional infrared satellite and radar imagery showed a maturing MCS over the Lower Mississippi Valley with a broken line of leading thunderstorms bowing southeastward along the southern AR/MS border, with a recent motion of 30-40 kt. The corresponding outflow boundary stretched northwestward into west-central AR, and has exhibited much slower forward progression over the past 2-3 hours compared to the locations farther east. Meanwhile, a combination of area 00Z soundings and the 01Z SPC mesoanalysis indicated the environment to the southwest of the outflow boundary (OK/AR border into the ArkLaTex) contained large MLCAPE values of 2000-4000 J/kg along with precipitable water values of 1.6 to over 2 inches. However, much of that moisture was focused in the surface to 800 mb layer with relatively low RH values above 700 mb noted in area soundings and Layered PW imagery, which may contribute to dry air entrainment and outflow. An area of low level confluence was observed in area 850 mb VAD wind plots, coincident with an area of cumulus in fading visible imagery over eastern OK, located just ahead of a slow moving cold front. Low level confluence and a mean westerly direction of 15-25 kt at 850 mb will have the potential to produce nocturnal convection over far eastern OK into western AR, with overrunning of the AR outflow boundary a contributing factor over the next 3-6 hours. Storm movement toward the southeast, or quasi-parallel to the outflow boundary over the western half of AR, may act to support training of thunderstorms, at least in the short term. Short term training will also be possible over far eastern OK, displaced away from the AR outflow boundary. The very moist/unstable environment should have the potential to produce 2-3 in/hr rates, which could produce localized flash flooding over typically sensitive locations. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-n2xPX3DRzrIxS4w5IqtpPvaPJOCJCnz4gQrSaa1Eb-VlZxRzWv5g8wx_1BggEIKrsA5= ujxXf4UXftfIgB15nO0aFc0$ for graphic product... ATTN...WFO...JAN...LZK...SHV...TSA... ATTN...RFC...ABRFC...LMRFC...NWC... LAT...LON 35509438 35499356 34859224 34549176 33979154=20 33279169 33199213 33489300 34139427 34689556=20 35159527=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) .