Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Nov 04 2022 20:32:41 AWUS01 KWNH 042032 FFGMPD LAZ000-MOZ000-ARZ000-TXZ000-OKZ000-050230- Mesoscale Precipitation Discussion 1110 NWS Weather Prediction Center College Park MD 430 PM EDT Fri Nov 04 2022 Areas affected...Northeast TX...Southeast OK...Western AR Concerning...Heavy rainfall...Flash flooding possible Valid 042030Z - 050230Z SUMMARY...Organized bands of strong to severe thunderstorms this afternoon and evening may produce enough short-term rainfall for there to be an isolated threat of flash flooding. The urban corridors will be at greatest risk. DISCUSSION...Radar imagery shows multiple clusters of heavy showers and thunderstorms now impacting portions of the Red River Valley of the South, and this activity is expected to continue to generally grow upscale and attain more vigor over the next several hours as a strong upper-level trough ejects east-northeast out across the southern High Plains. GOES-E IR satellite imagery shows some impressively cold convective tops currently with the activity northeast of Dallas, TX and with the clustering of storms around the McAlester, OK vicinity. The ejecting upper-level trough will be interacting with strong moisture and instability transport up across the southern Plains and lower MS Valley heading well into the evening hours, and thus leading the way for widespread and organized bands of convection. In fact, the latest RAP analysis shows a nose of MLCAPE values reaching 1500 to 2000+ j/kg up across the Red River of the South, along with PWs approaching 1.75 inches. This is being strongly aided by a confluent and vigorous low-level jet approaching 50 kts. Meanwhile, the kinematic wind field through the column is favoring enhanced shear profiles, with effective bulk shear on the order of 50 to 60 kts. This combination of robust thermodynamic and shear parameters will lead the way for upscale growth and organization of convection for the Arklatex region in particular over the next few hours. Please see SPC's Day 1 Convective Outlook and Tornado Watch #560 concerning the expectation of severe weather this afternoon and evening. Aside from the severe weather hazards, there may be just enough of a heavy rainfall footprint to also foster an isolated threat of flash flooding. The key to this will be getting these bands of convection to locally train over the same area, and with sufficiently heavy enough rainfall rates. The urban corridors will generally be at greatest risk of seeing runoff problems. The 12Z HREF guidance does support some periodic training of some of these bands of convection heading through the late afternoon and evening hours, with some rainfall rates capable of reaching 1.5 to 2.5 inches/hour. The higher PW environment and strong moisture transport regime working in tandem with the moderate to strong instability profiles will facilitate these enhanced rates. Some localized swaths of 2 to 4+ inches of rain are expected across areas of southeast OK, northeast TX and into western AR heading through the early to mid evening hours. The flash flood threat should overall be isolated in nature, with again the urban corridors at greatest risk. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!9tSmDMj-D7kdoGnmVKwYC4gR5LUJr1DXLQwY_ZQD3R6YCL5zMPFeZ9nCU_I1SZa7u-UW= Hc9pLRAzbhzpytvuHRnaUsE$ for graphic product... ATTN...WFO...FWD...LZK...OUN...SGF...SHV...TSA... ATTN...RFC...ABRFC...LMRFC...WGRFC...NWC... LAT...LON 36619396 36499297 35859270 33979343 32789418=20 32029531 32289637 32839684 34059681 35439595=20 36169514=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) .