Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Mar 24 2023 02:16:13 AWUS01 KWNH 240216 FFGMPD OHZ000-KYZ000-INZ000-ILZ000-MOZ000-240800- Mesoscale Precipitation Discussion 0120 NWS Weather Prediction Center College Park MD 1015 PM EDT Thu Mar 23 2023 Areas affected...Southern IL...Southern IND...Southwest OH...Parts of Northern KY... Concerning...Heavy rainfall...Flash flooding possible Valid 240215Z - 240800Z SUMMARY...Deep confluent layer favoring continued training profile with occasional strong embedded convective cells tracking through the line. Scattered incidents of flash flooding are possible with scattered 2-3" totals by 09z. DISCUSSION...GOES-E WV suite depicts a very impressive anticyclonically curved cirrus shield expanding across the Mid-Mississippi Valley into IL and IND and is associated with the right entrance region to the very strong 150kt 3H jet across the Great Lakes. A flat speed induced 5H shortwave is lifting across S MO and is strengthening the LLJ out of Arkansas into the Lower Ohio River Valley. This shortwave will continue to remain flat/elongated across the area of concern while keeping the mean deep layer flow fairly unidirectional to support a favorable training repeating environment. CIRA LPW along with RAP analysis denote this LLJ is starting to pool deeper layer moisture along the axis of concern in the Lower Ohio River Valley, with Total PWat values starting to reach 1.4 to 1.5 across MO into S IL. 02z surface analysis denotes the surface front is a bit south across S MO and ext S IL/SW IND before becoming a bit looser defined into SE IND with a weak inflection nearing CVG. The moistening of the mid-levels is reducing lapse rates and so instability is weakening along and south of the boundary. Still, the surface flow is contributing to some moisture flux convergence along the front to initiate scattered thunderstorms, though are not as dense as the 850mb gradient boundary is a bit further north closer to the better upper-level divergence axis. This is resulting is a split of activity with stronger cells along the front but should be in short duration, yet, the low to mid-level convergence flux boundary shows more dense activity across SE MO into S IL and starting in IND. Activity will be displaced from best instability and rainfall rates should be a bit more moderate in nature. However, the duration will be longer and with occasional embedded stronger cores may still reach 1-1.25"/hr rates through the next few hours as it expands eastward into SE IND/SW OH. This should result in streaks/narrow axis of 2 to possibly localized 3" totals through 09z which may result in possible scattered incidents of flash flooding through the early morning hours. Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8LZzXR7hebBP4UGT31P6VPgCE0ww9eOIMW8vUcuIamgDLphLClubWsuTYWhOXWWBWVqO= JwVUhldkrn7Um3pRH-aOR6g$ for graphic product... ATTN...WFO...ILN...ILX...IND...LMK...LSX...PAH... ATTN...RFC...LMRFC...NCRFC...OHRFC...NWC... LAT...LON 39828600 39778323 39218287 38678358 37688647=20 37088890 37698977 38799000 39348881 39608761=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) .