Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Aug 05 2023 00:12:42 AWUS01 KWNH 050012 FFGMPD ILZ000-MOZ000-IAZ000-050600- Mesoscale Precipitation Discussion 0865 NWS Weather Prediction Center College Park MD 811 PM EDT Fri Aug 04 2023 Areas affected...Missouri...Extreme western Illinois... Concerning...Heavy rainfall...Flash flooding likely Valid 050010Z - 050600Z SUMMARY...Flash flooding to continue across northern Missouri with expanding thunderstorm development along flanking mid-level trof into S MO. Cells will cross fully saturated grounds likely to induce another bout of flash flooding into the early overnight hours. DISCUSSION...GOES-E WV suite denotes a well defined MCV/Shortwave across north-central MO continuing to slowly drift eastward under continued favorable upper-level outflow pattern. The imagery in combination with CIRA LPW denotes a narrow stripe of enhanced deep layer moisture pooling along the shortwave's effective trailing mid-level trof; north of which mid-level dry air is rotating into the system across central MO. Strong convective response remains within the southeast quadrant of the circulation inducing a surface low near CDJ, with effective frontal structure oriented in a classical manner with warm front from IRK to HAE to STL/BLV.=20 Deep moisture remains pooled near the centroid with 2.25"+ total PWat, which extends along and southeast around the effective warm front through the Mississippi Valley with 2-2.4" values strung out, with 2"+ values along the trailing mid-level trof from NE OK into S MO. The dry air aloft has steepened lapse rates for very high instability along/ahead of the effective cold front into the dry slot, though deeper moisture intersection near the surface low and northward should have ample narrow skinny CAPE for strong updrafts and moisture flux for 2-3"/hr rates into the overnight period.=20 Slow, nearly due eastward progression of the MCV/surface wave should keep orientation of some cells to align favorably for longer duration and support a swath of highest rainfall totals of 3-5". Some guidance suggests higher values, but reduced instability and updraft strength may limit the rates to more extreme values, but a spot of 6"+ cannot be fully ruled out through this axis. Southward, stronger updrafts with some rotation should support very strong isallobaric response for extreme moisture flux convergence. Instantaneous rates will be very high in this efficiency, but forward speed will likely limit overall totals. However, streaks of 2-4" are probable with the cores of these supercells and as they cross compromised soils from Saline to Madison county are likely to once again induce flash flooding.=20 Cells within the core of the dry slot should be fastest moving; however, southward in the anticyclonic rotor of the dry slot punch, forward propagation may be a bit slower and in proximity to the aforementioned deeper moisture axis, some back-building will be possible and cell motions will be slower, again allowing for slightly increased totals of 2-5" are possible but should become more scattered in nature due to slightly less favorable deeper layer convergence further from the MCV.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!5LybOnO9fyil5xhSG_37qZbuKf_FWWWnP44YGuHD0MjzHiQO_QUCRJuLUuNUkN8SSZZX= 7Y82Mks7Xd8peb0fwXyZiyE$ for graphic product... ATTN...WFO...DMX...DVN...EAX...LSX...SGF... ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...NWC... LAT...LON 40869346 40809291 40459204 40149146 39789102=20 39209039 38089019 37319079 36719198 36519374=20 36789427 37229370 37809288 38409279 38869364=20 39039386 39399431 39639448 39989461 40439452=20 40819409=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) .