Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Apr 19 2024 01:59:36 AWUS01 KWNH 190159 FFGMPD TNZ000-KYZ000-INZ000-ILZ000-MOZ000-ARZ000-190700- Mesoscale Precipitation Discussion 0164 NWS Weather Prediction Center College Park MD 958 PM EDT Thu Apr 18 2024 Areas affected...sern MO/nern AR into lower OH Valley and nwrn TN Concerning...Heavy rainfall...Flash flooding possible Valid 190157Z - 190700Z SUMMARY...Short term training of thunderstorms from west to east may result in localized flash flooding from 2-3 inches of rain. The threat will extend through 07Z for portions of southeastern MO into northeastern AR, and eastward into the lower OH Valley and northwestern TN. DISCUSSION...Infrared imagery and 01Z surface observations helped identify a cold front extending from a surface low in west-central IL, southwestward into northwestern AR. A line of thunderstorms was located in southeastern IL, well out ahead of the cold front, arcing southwestward into southeastern MO (with gaps in intensity) where the line was more coincident with the frontal boundary. While the presence of hail may be over-inflating MRMS rainfall estimates, peak rainfall rates were averaging between 1-2 in/hr over the past few hours according to MRMS data. The cold front is forecast by the model consensus to continue a steady movement toward the southeast through at least the first half of the night, limiting flash flood concerns just considering movement of the boundary. However, given radar trends and short term extrapolation of the leading line of thunderstorms in IL, moving out ahead faster than the portion of the line in MO, there could be some portions of the convective line that orient parallel to mean steering flow, supporting at least a short period of training. Where/if this occurs, rainfall rates of 1-2 in/hr could result in 2-3 inches of rain in roughly a 2 hour window. 925-850 mb winds from the SSW at 01Z were focusing the best low level moisture transport up the MS River Valley and this axis is expected to edge eastward over the next few hours while gradually veering through 06Z. The flash flood threat is expected to decrease beyond 06Z with reducing instability and veering low level flow, in line with the hires model consensus, but trends will be monitored for changes to the forecast evolution. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!_FzBSrXjEm7Ijrj0XMmQDbGjItHZE1rLmtxaKP7G8Ko7jdDSEMn3ysRPl2tXp7-cucmI= Qz5pEfufwGnqXXpsK6-bGpU$ for graphic product... ATTN...WFO...LMK...LSX...LZK...MEG...OHX...PAH...SGF... ATTN...RFC...LMRFC...NCRFC...OHRFC...NWC... LAT...LON 38238735 38058667 37598622 36728621 36268650=20 36078727 35988819 35858968 36099170 36619216=20 36699211 37039149 37349083 37748961=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) .