Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jul 02 2023 18:37:59 AWUS01 KWNH 021837 FFGMPD OHZ000-TNZ000-KYZ000-INZ000-ILZ000-MOZ000-ARZ000-030030- Mesoscale Precipitation Discussion 0622 NWS Weather Prediction Center College Park MD 237 PM EDT Sun Jul 02 2023 Areas affected...Bootheel of MO...Much of KY...Southern IL...Southern IND...Ext Southwest OH...Ext Northwest & North-Middle TN... Concerning...Heavy rainfall...Flash flooding possible Valid 021835Z - 030030Z SUMMARY...Highly efficient thunderstorms but quick moving thunderstorms may have short-term training & back-building elements. Narrow streaks of 2-3" totals are probable and may align with saturated soils from recent flooding conditions over S IL/IND and NW KY, posing the greatest risk for flash flooding. DISCUSSION...GOES-E WV denote a favorable forcing environment across the Lower Ohio River Valley again today as the based of the compact upper level low over northeast IL rotates across S IL providing broad scale DPVA for favorable ascent. CIRA LPW denotes a disjointed deep layer moisture pattern, with the core of the mid-level (700-500) dry slot currently across the Bootheel into W KY toward N KY, though some mid-level return moisture in the 850-700 has returned around the base of the trough/older TROWAL, bleeding into S IL/S IND. Surface moisture due to ample solar heating is evaporating some soil moisture resulting in upper 70s and low 80s Tds, generally collocated with the dry slot. As such, there is some modest dry air in the column, but overall the moisture values remain above 1.75" while still allowing for some increased lapse rates for stronger updrafts.=20 These updrafts will work well along the a 2000-3000 J/kg MLCAPE gradient to result in stronger inflow and moisture flux and given minor loss to evaporation, should still be efficient rain producers, particularly with time... rates of 1.75-2"/hr are likely with some short-term up ticks to 2.5" possible. The question for flash flooding will be duration; which given the strong deep layer flow will result in fast storm motions.=20 However, favorable upstream inflow along the 850-700 streamlines should support back-building particularly along an ahead of the base of the trof in S IL. Given the steering flow and propagation vectors are fairly aligned and unidirectional, flanking cells should train in the short term, suggesting streaks of 2-3" are possible. Additionally, other clusters/lines of cells should develop upstream and allow for repeating tracks over 3-5 hours across West-central to Central KY adding to a more buckshot appearance to the 2-3" total pattern. This alone, may result in nuisance flooding across the area, but recent very heavy rainfall has saturated much of the area of concern (less so the west and far eastern portions), and low FFG values dot the area, combined with urban center/bluffs of the OH river and NE KY...have added those drier areas for the potential flash flooding incidents through late evening. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8nf0BfANQIcQ9Awqb-k7hd_z960r0-x-9ZACrCnLchrscBntjOuXvcj1imNXQntbAwmw= MSAOxJ4A4bKI_e6FEY-uRRY$ for graphic product... ATTN...WFO...ILN...IND...JKL...LMK...LSX...MEG...OHX...PAH... ATTN...RFC...LMRFC...NCRFC...OHRFC...NWC... LAT...LON 39478464 38968352 37868347 37048423 36598544=20 36208928 36299055 37319069 37908963 38228849=20 38518762 39198608=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) .