Flash Flood Guidance
Issued by NWS
Issued by NWS
162 AWUS01 KWNH 141001 FFGMPD GAZ000-TNZ000-ALZ000-MSZ000-141600- Mesoscale Precipitation Discussion 1007 NWS Weather Prediction Center College Park MD 600 AM EDT Sat Sep 14 2024 Areas affected...Western and Middle TN...Far Northeast MS...Northwest to Southeast AL...Southwest to Central GA Concerning...Heavy rainfall...Flash flooding possible Valid 141000Z - 141600Z SUMMARY...Locally slow-moving and occasionally training bands of heavy showers and thunderstorms is expected to maintain a threat for some areas of flash flooding going through the morning hours. DISCUSSION...Generally there has not been much change over the last several hours to setup and character of the heavy rainfall threat that continues to impact areas of the Mid-South. The latest GOES-E IR satellite imagery coupled with dual-pol radar continues to show some broken bands of showers and occasionally some thunderstorms across portions of western and middle TN down through much of northwest and central AL. Some weaker and more disorganized convection is seen over parts of southeast AL. This is all in association with what is left of Post-T.C. Francine. There continues to be an axis of persistent moisture convergence and modest instability oriented in a north-northwest to south-southeast fashion across the region, with MUCAPE values of 500 to 1000 J/kg and PWs of 1.75 to 2.0 inches. A very gradual cyclonic pivoting of the convection has been occurring over the last few hours as the ill-defined center of Post-T.C. Francine and its frontal occlusion tends to lose latitude. Going through the morning hours, some additional focus for broken bands of convection should continue with some additional likelihood for some cell-training. This will be favored by a persistent fetch of at least modest moisture transport and instability around the eastern flank of the weakening frontal occlusion. Rainfall rates with the stronger convective cores may reach 1 to 1.5 inches/hour this morning and this is consistent with the 00Z/06Z HREF guidance. Recent HRRR runs suggest that there could be some potential for convection to develop and perhaps become locally a bit more concentrated farther down to the south and east across areas of southeast AL and into parts of southwest to central GA but there is more model spread overall with the details of this. Some additional spotty rainfall totals this morning of 2 to 4 inches will be possible where any additional cell-training occurs, and given the wet antecedent conditions across most of the region, this may foster some additional runoff concerns and possible flash flooding. Orrison ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...BMX...FFC...HUN...JAX...MEG...MOB...OHX...TAE... ATTN...RFC...LMRFC...SERFC...NWC... LAT...LON 36188789 35748724 34788633 33388506 32428274 31608259 31058344 31118518 31668619 33158712 34088787 34928893 35558908 36138869