Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Apr 05 2023 16:50:04 AWUS01 KWNH 051649 FFGMPD OHZ000-KYZ000-INZ000-052245- Mesoscale Precipitation Discussion 0158 NWS Weather Prediction Center College Park MD 1249 PM EDT Wed Apr 05 2023 Areas affected...far northern KY, central/southern IN into OH Concerning...Heavy rainfall...Flash flooding possible Valid 051646Z - 052245Z Summary...Rainfall rates are expected to occasionally exceed 1 in/hr across portions of the OH River into IN and OH, leading to 2-hour rainfall totals of 1.5 to 2+ inches. Portions of this region have low flash flood guidance values and could see localized excess runoff. Discussion...Regional radar imagery at 1630Z showed a broken line of thunderstorms stretching from central IN into southeastern MO, located well east of a cold front that was located in central IL. MRMS has shown 1-hr rainfall occasionally exceeding 1 in/hr across MO into IL where line orientation has matched the deeper layer steering flow but the axis of thunderstorms has generally not resulted in rainfall totals in excess of 1 to 1.5 inches over MO into southern IL. MLCAPE across the Lower OH Valley was 500-1500 J/kg per 16Z SPC mesoanalysis data with little to no CIN present, despite widespread cloud cover given the advection of low level moisture from the southwest on 50-60 kt of 850 mb flow. Radar imagery over the past hour has shown some convective development just ahead of the advancing convective line over southern IL that is likely to fill in over southern IN within the next 1-2 hours. Short term RAP forecasts indicate some increase in diffluent and divergent flow in the upper levels over the lower/middle OH Valley through 22Z as an estimated 150 kt jet streak near 250 mb advances northeastward into the Upper Midwest. This region of the OH Valley has experienced 200 to 300 percent of average rainfall over the past 2 weeks with locations continuing to experience elevated soil moisture values per NASA SPoRT imagery. The main concern for flash flooding is where short term orientation of heavier echoes align with the deeper layer mean wind, allowing for training and possible 2 hour rainfall of 1.5 to 2+ inches. Given flash flood guidance values as low as 1 to 2 inches in 3 hours for portions of the region, some localized flash flooding could occur if training of heavy rain falls over hydrologically sensitive locations. However, any instances of flash flooding should remain localized. Otto ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!6bdc3Ir_FX1KSQBxWOOrG_YDQLAYZXyK86U_BOR-_DEHHIhBiiiMHqpRFIsErWHV15e-= g5C6g-C2xB18MnjL6iNvmY0$ for graphic product... ATTN...WFO...CLE...ILN...IND...IWX...LMK...PAH...PBZ...RLX... ATTN...RFC...OHRFC...NWC... LAT...LON 41468159 40668143 39808256 38848397 37958647=20 38328738 39468712 40248572 41288329=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) .