AWUS01 KWNH 201654 FFGMPD GAZ000-ALZ000-MSZ000-202300- Mesoscale Precipitation Discussion 0481 NWS Weather Prediction Center College Park MD 1253 PM EDT Sat Jun 20 2026 Areas affected...Northern Mississippi, Alabama, Southwest Georgia Concerning...Heavy rainfall...Flash flooding possible Valid 201700Z - 202300Z Summary...Showers and thunderstorms will expand along a warm front this afternoon and then train slowly along the boundary. Hourly rainfall exceeding 2 inches is likely, with total rainfall of 3-5+" possible. This will produce an increasing risk for flash flooding. Discussion...An active afternoon is continuing across portions of the Southeast, with widespread showers and thunderstorms occurring from Texas to Alabama. On the northern edge of the most active weather so far today, Cu and TCu with increasing glaciation is noted in the GOES-E experimental day-cloud RGB, suggesting thunderstorms will rapidly develop from far northern MS through northern/central AL and into western GA. This enhanced cloud development is occurring along a warm front/stationary front analyzed by WPC, with ascent aided both by subtle height falls within a broad mid-level trough axis, and weak but persistent RRQ diffluence as a jet streak pivots to the northeast. This ascent is acting upon impressive thermodynamics characterized by PWs measured by GPS of 1.9 to 2.2 inches, well above the 90th percentile for the date, overlapping MLCAPE that has recently eclipsed 1500-2000 J/kg according to the SPC RAP analysis. Within this environment, showers and thunderstorms have contained robust rain rates measured via MRMS as high as 0.5-0.6"/15 min (2+"/hr) in many areas. It is likely that as the atmosphere destabilizes further and pronounced SW flow surges the tropical moisture even farther northward, rain rates could become even more impressive. Both the REFS and HREF indicate a 40-60% chance for at least 2"/hr rainfall, while the sub-hourly HRRR indicates up to 0.75"/15 min (3"/hr rates). This indicates a high confidence in 2-3"/hr rainfall rates in any deep convection, and these cells will likely develop and regenerate along the front thanks to isentropic ascent/convergence, and then train E/SE on mean flow of just around 10 kts. This setup is favorable for prolonged training from NW to SE in the vicinity of the front and this could produce 3-5" of rainfall with locally higher amounts possible (20% chance). Soils across this region are already primed as reflected by NASA SPoRT 0-40cm soil moisture above the 95th percentile and 3-hr FFG that is generally around 2.5". While the greatest risk for flash flooding will be across urban areas including Tupelo, MS, Birmingham, AL, and Columbus, GA, any locations that receive training heavy rainfall atop these sensitive soils could experience flash flooding impacts. Weiss ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...BMX...FFC...HUN...JAN...MEG...MOB...TAE... ATTN...RFC...ALR...ORN...NWC... LAT...LON 34928946 34788825 34458722 34058624 33038398 32428358 32028372 31668388 31318425 31168479 31268539 31578625 31888690 32328749 32858828 33198886 33478925 34108997