Flash Flood Guidance
Issued by NWS
Issued by NWS
971 AWUS01 KWNH 220155 FFGMPD ILZ000-MOZ000-IAZ000-KSZ000-NEZ000-220700- Mesoscale Precipitation Discussion 1040 NWS Weather Prediction Center College Park MD 954 PM EDT Sat Sep 21 2024 Areas affected...Mid-MO Valley into southern IA/northern MO Concerning...Heavy rainfall...Flash flooding possible Valid 220153Z - 220700Z SUMMARY...Brief training of 1 to 3 in/hr rainfall rates may support localized flash flooding across portions of the MO River Valley into southern IA/northern MO through 07Z. DISCUSSION...0145Z radar imagery showed an expanding line segment of strong to severe convection extending from southeastern NE into far northwestern MO and southwestern IA. Additional convection was noted to be racing eastward across eastern KS. These storms were located just ahead of a wavy cold front and ahead of a low to mid-level vorticity max in northeastern KS, observed on KTWX radar imagery, advancing toward the northeast. A small ribbon of instability was in place ahead of the cold front with 1000 to 2000+ J/kg MLCAPE and PWATs between 1.8 and 2.0 inches via the 01Z SPC mesoanalysis. Through 08Z, the cold front and instability are forecast to continue advancing south and east while forcing ahead of the northeastern KS vorticity max aids in lift with additional thunderstorms likely to fill in across the MO/IA border. There will be an overall progressive movement to individual cells and instability should trend downward with time, but repeating/training will also occur at times allowing for 1 to 2, perhaps as high as 3 in/hr rainfall rates to occur. These high rates could lead to short term rainfall totals of 3-4 inches in an isolated location or two. While dry antecedent conditions will likely limit the coverage of flash flooding, one cannot rule out urban or otherwise sensitive terrain being impacted by rapid rises of water. Otto ...Please see www.wpc.ncep.noaa.gov for graphic product... ATTN...WFO...DMX...DVN...EAX...LSX...OAX...TOP... ATTN...RFC...MBRFC...NCRFC...NWC... LAT...LON 41909358 41729253 41389184 40989149 40369132 40119156 40029204 39969270 39849386 39709523 39889618 40659533 41539467