Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Apr 18 2024 21:23:01 AWUS01 KWNH 182122 FFGMPD ALZ000-MSZ000-LAZ000-ARZ000-190100- Mesoscale Precipitation Discussion 0163 NWS Weather Prediction Center College Park MD 521 PM EDT Thu Apr 18 2024 Areas affected...Arklamiss into north-central MS Concerning...Heavy rainfall...Flash flooding likely Valid 182119Z - 190100Z Summary...Localized but likely flash flooding to persist while translating east for another few hours into central MS through 00Z. Rainfall rates over 2 in/hr can be expected. Discussion...21Z radar imagery continued to show a west-east axis of thunderstorms extending from the eastern AR/LA border into central MS, with MRMS hourly rainfall totals over 2 inches at times. MRMS-derived rainfall over the past 6 hours (ending 21Z) is near 10 inches along the southern Ashley/Chicot County border, and while MRMS rainfall matches a Wunderground.com station just west of Eudora, AR with 5.74", this region resides within the melting layer of the 3-nearest WSR-88Ds, and uncertainty exists with the actual highest rainfall totals given a lack of ground truth. Regardless, significant rainfall has fallen within a relatively short period of time near the AR/LA/MS border with ongoing flash flooding. A mid to upper level shortwave was observed to be moving east along the central AR/LA border with diffluent flow downstream. Radar/infrared imagery downstream of the shortwave into central MS has shown some signs of losing organization over the past hour. Despite that fact, the environment will continue to favor training heavy rain for the next 1-3 hours to the north of an outflow boundary analyzed from northern LA into central MS with 20-35 kt of SSW 925-850 mb flow in northern LA overrunning the rain-cooled airmass. While some near term weakening of the low level flow will be possible, MLCAPE estimates just south of the outflow boundary were 1000 to 2000+ j/kg via the 21Z SPC mesoanalysis and as the shortwave aloft continues to advance toward the east, areas of heavy rain with training will shift downstream into portions of central MS through 00Z. Peak rainfall rates over 2 in/hr will remain possible at times and and an additional 2-5 inches is expected for localized areas through 00Z or 01Z. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!-fDxTqEx-NUBjIQt4H3jBuQo-MNZYLl-ky9kj7MH9a1rwC7KyB2cgxm9ZjS_48nQyS4V= ueHt9GmStub4AFK9h-mUXsc$ for graphic product... ATTN...WFO...BMX...JAN... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 33628913 33538823 33068814 32418824 32268905=20 32339032 32579130 33049166 33379130 33529039=20 =20=20=20=20=20=20=20=20=20=20=20=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) .