Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Mar 27 2023 06:30:22 AWUS01 KWNH 270630 FFGMPD GAZ000-ALZ000-MSZ000-271230- Mesoscale Precipitation Discussion 0137 NWS Weather Prediction Center College Park MD 229 AM EDT Mon Mar 27 2023 Areas affected...Central AL...Central GA Concerning...Heavy rainfall...Flash flooding possible Valid 270630Z - 271230Z SUMMARY...Additional rounds of weaker but still potent showers/thunderstorms tracking through already saturated grounds with additional 1-3" totals may maintain/re-aggravate flash flooding across the area through daybreak. DISCUSSION...GOES-E WV, RADAR mosaic depict quick moving southern stream shortwave continues to lift away from the region into the upstate Carolinas though the vestiges of the trailing mid-level trof and connection to anomalous moisture slug across the northwest Gulf and central Gulf states remains attached if continually stretched to its limits. Surface and instability analysis denote a broad area of 1500-2000 J/kg of weakly capped MLCAPE along and south of the convectively reinforced frontal boundary/outflow across central GA back to central AL. Oblique isentropic ascent and low level moisture convergence continue to support/activate new thunderstorms upstream, currently in Lowndes to Lee county training fairly well under increasingly unidirectional steering flow. The oblique nature is not supporting broad continuous thunderstorms but sufficient for moderate to heavy rainfall still with 1.5"+ Total PWats to maintain the potential for 1.5"/hr rates. Given the length, the potential for an additional 2-3" remains while crossing saturated grounds it remains probable to induce or re-aggravate ongoing flooding/flash flooding across this area in the next few hours as it migrates into W central GA (where 4-6" fell throughout the day). An additional band is developing under slightly backed 850mb flow to activate a bit more elevated across far western MS into W central AL from Kemper to Bibb counties. This backing appears to be in response to the approaching synoptic height-falls and frontal zone currently over western to middle TN across S AR.=20 This boundary is expected to sharpen/congeal with the boundary across E LA/S MS. Increasing low level confluence/convergence, supporting additional activity. This pre-frontal activity will be the last cells, and are likely to slide quickly from WNW to ESE with capability of dropping an additional 1-2". Given the saturated areas from earlier rainfall east of I-59 from Meridian to Laurel and across central AL, these too are likely to aggravate any ongoing flooding conditions. It is not a guarantee to rise to the level/rates to induce new areas of rapid inundation but it remains clearly possible, especially if pre-frontal cells sprout up along/ahead of the line to merge with this cold front line. Downstream into central GA, the exiting wave will keep the unidirectional flow solid for well into the early morning hours and corral these lines of cells probably into a more concentrated line/confluent line. Unfortunately, trends in the Hi-Res guidance and RADAR trends suggest this will overlay areas most affected throughout the day maintaining the flash flooding risk across the eastern portion of the MPD area of concern through 12/13z. As such flash flooding continues to be likely.=20 Gallina ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!4iMm_NUmW_q_iv53npXY-Ahzj70OJPMnXXLvh6nKT5dMxAmlTM9NOlIKZFLgnuR1rvVk= Xo58Nv_oa2aewuaK16xlduc$ for graphic product... ATTN...WFO...BMX...FFC...JAN...MOB... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 33798375 33768303 33288274 32668364 32178617=20 31768801 32078881 32998866 33248760 33428617=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) .