Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Apr 21 2023 02:07:13 AWUS01 KWNH 210207 FFGMPD TNZ000-ILZ000-LAZ000-MOZ000-ARZ000-TXZ000-OKZ000-210800- Mesoscale Precipitation Discussion 0202 NWS Weather Prediction Center College Park MD 1005 PM EDT Thu Apr 20 2023 Areas affected...Ark-La-Tex and Surroundings into North-Central AR and southeastern MO Concerning...Heavy rainfall...Flash flooding likely Valid 210200Z - 210800Z Summary...Isolated to scattered instances of flash flooding are likely to continue through the early overnight hours as convection is renewed along and ahead of a slow moving cold front. Additional localized totals of 2-4 inches are expected, and an isolated instance or two of significant flash flooding is possible. Discussion...Areas of convection are gradually moving eastward across the Ark-La-Tex and portions of the Lower MS Valley, with MRMS estimates over the past 6 hours as high as 1.5-3.5 inches locally. These higher totals have mostly fallen across the Ark-La-Tex region (but more specifically near the intersection of OK/AR/TX). Localized flash flooding is ongoing across some of these areas, and isolated to scattered instances of flash flooding are likely to continue into the overnight hours across much of the same areas. This is due to expectation of renewed convection along a slow moving cold front, due to a combination of a shortwave impulse digging in from the Southern Plains and a strengthening low-level jet (to 20-30 kts) and associated moisture transport. Meanwhile, the mesoscale environment appears to still be supportive of heavy rainfall, as precipitable water values range from 1.4-1.7 inches (near the max moving average per LZK sounding climatology), MU CAPE of 500-1000 J/kg, and effective bulk shear of 30-40 kts. As of the time of writing, there are already signs of this renewed convection occurring in the vicinity of the OK/AR/TX with strong updrafts persisting, as indicated by very cold cloud tops via GOES-East IR imagery. Recent HRRR runs (hourly from 21-00z) have been performing much better than the HREF (as expected prior to the imminent arrival of the new 00z HREF). These runs indicate additional localized totals of 2-4 inches, and this seems reasonable given the described meteorological conditions. Consequentially, an isolated instance or two of significant flash flooding appears possible (due to the overlap of earlier rainfall and the expected continuation of 1-2"+/hr rates). This risk is highest in the vicinity of the OK/AR/TX border region, extending northeastward to near Little Rock. Churchill ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8mlcBA-JmppOBEHjHr7j6qrYfQd5aDkpUvQgsnee-TkSvEcjl_fmSU19e5t9k8FJUj2X= bVkLTV_GMu9ZtstIshh5r3c$ for graphic product... ATTN...WFO...FWD...LSX...LZK...MEG...OUN...PAH...SGF...SHV... TSA... ATTN...RFC...ABRFC...LMRFC...NCRFC...WGRFC...NWC... LAT...LON 37739082 37348945 36288963 35039036 34049136=20 33859226 33339298 32709373 32109437 32069566=20 32219638 32609667 33549630 34359549 34839482=20 35399426 36079323=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) .