Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Mar 15 2025 13:22:32 AWUS01 KWNH 151321 FFGMPD GAZ000-TNZ000-ALZ000-151630- Mesoscale Precipitation Discussion 0062 NWS Weather Prediction Center College Park MD 920 AM EDT Sat Mar 15 2025 Areas affected...Northeastern Alabama, Far Northwestern Georgia, and Southeastern Tennessee Concerning...Heavy rainfall...Flash flooding possible Valid 151319Z - 151630Z SUMMARY...Training cellular convection over northeastern Alabama may cause a localized flash flooding risk as they advect northeastward into the Chattanooga Metro. DISCUSSION...Cellular convection that has been largely stationary across northeastern Alabama this morning has been advecting northeastward into the Chattanooga Metro area this morning. Southeasterly surface flow characterized by dewpoints in the 50s is largely orthogonal to the northeastward moving and oriented line of convection. This has been feeding the storms and contributing to their persistence. The upper levels feature a bifurcated jet streak, with the storms in the middle of the bifurcation. It's possible the southern arm is contributing to upper level lift being in the divergence region of the jet. Much of the CAMs guidance suggests this area of storms will shift off to the north and join up with the line of storms well to its west over the next few hours. However, that remains to be seen, as the forcing would support the storms remaining in place. Following a persistence forecast, over the next few hours, heavier cells will be moving over the Chattanooga metro, which due to urban and terrain concerns poses a higher localized flash flooding risk. Most of the instability is west of the storms, with the southeasterly inflow not advecting much into the storms. Thus, there is some chance the storms fall apart on their own, but as that hasn't happened yet, the flash flooding threat will persist for the next few hours. At the very least, this offset of instability from the inflow should continue to limit the strength and maximum rainfall potential of the storms. Wegman ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!8mgvyMuJcn2-fNlM-3kPTK3NR5GcSLFrpfLYhsaijjuto0MX9J5U-5AtZQgL05dJGAt9= MxvhoQMMFQID5WhjD9kgCDg$ for graphic product... ATTN...WFO...BMX...FFC...HUN...MRX...OHX... ATTN...RFC...LMRFC...OHRFC...SERFC...NWC... LAT...LON 35748504 35588457 35168472 34748494 34158542=20 34048613 34088651 34828709 35388651=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) .