Subj : Flood Potential MOIAILIN To : All From : Mike Powell Date : Sun Dec 28 2025 09:05:01 AWUS01 KWNH 281003 FFGMPD MIZ000-INZ000-ILZ000-MOZ000-IAZ000-281600- Mesoscale Precipitation Discussion 1281 NWS Weather Prediction Center College Park MD 502 AM EST Sun Dec 28 2025 Areas affected...northern MO/southeastern IA/north-central IL/northwestern IN Concerning...Heavy rainfall...Flash flooding possible Valid 281000Z - 281600Z SUMMARY...Isolated flash flooding will be possible from portions of northern MO, southeastern IA into north-central IL and northwestern IN through 16Z (10 AM CST). Rainfall of 1 to 2 inches in an hour will be possible with isolated 3 to 6 hour totals of 2-3 inches. DISCUSSION...0945Z radar imagery Midwest showed scattered showers and embedded thunderstorms from northern MO, southern IA and central IL, located north of a quasi-stationary front that extended eastward from a 998 mb low just west of Salina, KS. SW to WSW 850 mb winds of 30-50 kt were in place to the east of the surface low with overrunning occurring atop the frontal boundary. OSPO ALPW imagery showed low level moisture rapidly advecting northward into the central U.S. beneath a plume of mid to upper level moisture with origins in the tropical eastern Pacific. Total PW values were estimated to be between 1.1 and 1.4 inches (SPC mesoanalysis) from eastern KS into western IN, which equate to +4 to +5 standardized anomalies. The low level moisture return was allowing for the northward advection of instability and erosion of low level CINH amid 700-500 mb lapse rates of 7.0 to 7.5 C/km, supporting MUCAPE of 500-1500 J/kg from eastern KS into western/central MO via 09Z SPC mesoanalysis data. This change in the thermodynamic environment has been reflected in recent infrared satellite imagery showing bursts of colder cloud tops over northern MO and far southern IA. As the surface low over central KS moves eastward early this morning, strengthening low level flow will translate into MO and IL with 850 mb speeds locally exceeding 50 kt. Convergence at the nose of 925-850 mb moisture transport will align WSW to ENE or parallel to the mean steering flow. This will set up narrow axes of heavy rainfall with training and potential for hourly rainfall between 1 and 2 inches. The best overlap of low level convergence with moisture/instability will be from northern MO into north-central IL and northwestern IN through 16Z. Isolated flash/urban flooding may result from 2-3 inches of rain in 2-3 hours. However, a lack of precipitation for this region of the U.S. over the past couple of weeks (lower than average soil moisture) and warmer than average temperatures (no/negligible frost depth) should limit runoff. Therefore, any flash flood concerns will likely be minor and remain limited to urban or sensitive low lying areas. Otto ATTN...WFO...DMX...DVN...EAX...ILX...IND...IWX...LOT...LSX... ATTN...RFC...KRF...MSR...TIR...NWC... LAT...LON 42178726 41658634 40918612 40448688 40038825 39629015 39199219 39289312 39699398 40409379 41329161 42118904 $$ --- SBBSecho 3.28-Linux * Origin: Capitol City Online (618:250/1) .