Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Mar 15 2025 20:46:48 AWUS01 KWNH 152046 FFGMPD FLZ000-ALZ000-MSZ000-LAZ000-160230- Mesoscale Precipitation Discussion 0065 NWS Weather Prediction Center College Park MD 446 PM EDT Sat Mar 15 2025 Areas affected...Eastern LA...Southeast MS...Southern AL.... Concerning...Heavy rainfall...Flash flooding possible Valid 152045Z - 160230Z SUMMARY...Lines of rotating cells are starting to congeal into a more single line and starting to advance eastward. Better alignment of moisture and instability axis will retain moisture flux to support up to 2"/hr rates; however, a more easterly component may reduce some training and therefore flash flooding will become more scattered in nature over higher FFG.=20 DISCUSSION...GOES-E WV suite depicts core of negative tilt shortwave has swung through Arkansas into the middle MS valley, this has resulted in low level veering and alignment of the moisture and instability axis across E LA into S MS. Currently, merging cells across the best confluence in S MS is resulting in higher than average rainfall rates (to other cells) due to slightly backed flow downshear of surface low near BTR. Moisture flux of 20-25kts of low 70s Tds and 2000-2500 J/kg of MLCAPE will maintain strong updrafts and efficient low level moisture flux convergence for rates of 2"/hr, perhaps as high as 2.5-3" for very short periods when isallobaric flow increases with cycling of updrafts/supercells.=20 Upper-level flow is starting to increase with overspreading of WSW 3H jet over 110kts, increasing easterly propagation component to the convective line. This will reduce training in the longer period, so supercells will continue to remain efficient along the line with streets of 2-3" totals possible. Combined with the generally higher FFG values across S MS/AL and E LA, flash flooding should become more scattered/isolated in nature as the line increases forward speed. However, there are numerous prone urban centers, particularly along I-10 that may be quickly over-whelmed by 1-2" sub-hourly totals if directly impacted by the leading broad downdrafts. As such, flash flooding is considered possible across the area of concern. An additional MPD will be issued subsequent to discuss higher likelihood flooding conditions further north.=20=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!47acq6U6UiFDtOn5lz9LnQ7bSRAEohWdHH8qHVXCHooew4f0BdlG2iwOFFw53xlugh5a= 2eMIAF4cfO_voMfiU4v6nrw$ for graphic product... ATTN...WFO...BMX...JAN...LIX...MOB... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 33398592 32748566 31788611 31128717 30488834=20 29839028 30519073 31999005 32718931 33318745=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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .