Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jul 02 2023 00:07:37 AWUS01 KWNH 020007 FFGMPD OHZ000-KYZ000-INZ000-ILZ000-MOZ000-ARZ000-020600- Mesoscale Precipitation Discussion 0618 NWS Weather Prediction Center College Park MD 807 PM EDT Sat Jul 01 2023 Areas affected...Southern IL...Southern IND...Southwest OH...Western to Northern KY...MO Bootheel... Concerning...Heavy rainfall...Flash flooding likely Valid 020005Z - 020600Z SUMMARY...Slow moving storms prior to MCS may preset ground before main line approaches. Trailing confluence trof over the Lower Ohio Valley, may support upstream redevelopment and potential for repeating cells crossing saturated grounds. DISCUSSION...Mature MCS continues a brisk progression through S IL with band of stronger thunderstorms along the leading edge. Very unstable downstream environment remains across Southern IND with a narrow string connecting back toward the Bootheel of MO between stable air in south-central KY and Middle TN; general 2000-2500 J/kg of MLCAPE remains uncapped. As such, localized sfc convergence has the potential to sprout new development downstream of the main faster moving line. These cells have been highly efficient with deep warm layer and ample total PWats over 2", resulting in 2.5"/hr rates before being absorbed into the main line. Line has a history of producing 1-1.5" totals in 15-30 minutes while passing per observations and 21z HRRR continues to suggest similar 15 minute totals until about an hour or so after night fall as it crosses into SW OH, but only diminishing toward .75-1"/15 minutes. Expanding moderate shield precipitation will allow for localized totals of 2-2.5" by 06z with higher values associated with those aforementioned slower moving pre-line storms. The area is crossing southern IND where recent heavy rainfall with 300-500% above normal per AHPS 7-day anomaly product, inferring saturated grounds and acceptable FFG values that are below 1.5"/hr. As such scattered flash flooding is considered likely. Further upstream into the Bootheel of MO... Trailing convergence/confluence line through 850-700mb exists within the deeper anomalous moisture plume, combined with 25-30kts of 850mb flow and 2-2.25" total PWats; standard anomalies of moisture flux are running about 3.5 to 4 for this time period. A subtle shortwave within the stream has backed low level flow a tad, supporting reduced Corfidi vectors across the Tri-River confluence area into S MO. Ample instability to 2000 J/kg and forcing from the approaching shortwave may allow for additional upstream development, while not likely numerous in coverage, there are solid signals in recent HRRR and Hi-Res CAM solutions to suggest potential repeating cells across SE MO into W KY this evening. Narrow bands of 2-3" are possible and within such flash flooding is possible. While confidence in this scenario unfolding is less than further up the Ohio River, the risk for this activity justifies the SW expansion of the area of concern through the overnight period. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8fHZsUvu6oYLmDUOeSOb9Cks75AqjdwMLOm7wGbZRiKPv1o3gAUxHPNZ5Eop5770mHSc= dZ4d2USICQiIbluW_TGJoH0$ for graphic product... ATTN...WFO...ILN...ILX...IND...LMK...LSX...MEG...PAH... ATTN...RFC...LMRFC...NCRFC...OHRFC...NWC... LAT...LON 40158527 40128443 39668361 38868366 37818547=20 36548859 36489042 37429073 38238871 39498636=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .