Subj : MESO: Heavy Rain/Flooding To : All From : Mike Powell Date : Thu Jan 25 2024 09:16:00 AWUS01 KWNH 251018 FFGMPD TNZ000-ALZ000-MSZ000-LAZ000-ARZ000-TXZ000-251615- Mesoscale Precipitation Discussion 0032 NWS Weather Prediction Center College Park MD 517 AM EST Thu Jan 25 2024 Areas affected...far southeastern TX into central LA, MS and northern AL Concerning...Heavy rainfall...Flash flooding likely Valid 251015Z - 251615Z SUMMARY...Heavy rain will move across portions of the Lower Mississippi Valley with peak rainfall rates of 1-2 in/hr through 16Z. Areas of flash flooding are expected given many locations across LA, MS and AL have saturated soils due to heavy rain over the past 24 hours. DISCUSSION...10Z regional radar imagery showed a continuous line of thunderstorms extending from southeastern TX into the western Gulf of Mexico, located just ahead of an advancing cold front in the region. The front and thunderstorms were located ahead of a well defined mid to upper level shortwave tracking to the ENE across west-central TX as seen on water vapor imagery. DPVA ahead of the shortwave and divergence aloft within the right entrance region of a 110 kt jet streak just east of the shortwave trough were providing strong ascent across the region which was characterized by 500-1500 J/kg MUCAPE per the 09Z SPC mesoanalysis. In the lower levels of the atmosphere, vAD winds from KHGX and KLCH sampled 25-30 kt at 850 mb from the south, supporting robust moisture transport from the Gulf of Mexico into the Gulf Coast states with recent GPS measured PWAT values ranging from 1.5 to 1.8 inches from southern LA to the central MS/AL border. As the mid to upper level shortwave and continues toward the northeast this morning, the associated cold front will steadily move east across LA, reaching western MS near 16Z. A solid line of thunderstorms is expected to follow the cold front's movement toward the east, preceded by warm advection induced pre-frontal convection at times. While the line should remain fairly progressive toward the east, brief training of heavy rain will allow for rainfall rates of 1-2 in/hr at times and additional totals of up to 3 inches through 16Z. These rains will be falling on top of 3 to 6+ inches of rain which fell from far southeastern TX into southern/central LA into south-central MS over the past 24 hours, leading to saturated soils in many locations. The addition of another 1-3 inches of rain, which may fall over a 1-2 hour window, is likely to lead to some renewed areas of flash flooding across LA into MS and perhaps northwestern AL through 16Z. Otto ATTN...WFO...BMX...HUN...JAN...LCH...LIX...MEG...MOB...SHV... ATTN...RFC...LMRFC...SERFC...WGRFC...NWC... LAT...LON 35108611 34348606 33128736 31858898 30539050 29619217 29499382 30149428 31569330 33219114 34668810 = = = --- SBBSecho 3.14-Linux * Origin: Ilink: CCO - capitolcityonline.net (454:1/105) .