FOUS30 KWBC 131555 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 1155 AM EDT Mon Apr 13 2026 Day 1 Valid 12Z Mon Apr 13 2026 - 12Z Tue Apr 14 2026 ...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF NORTH-CENTRAL TO NORTHEAST WISCONSIN AND NORTHWEST L.P. OF MICHIGAN... 16z update... 12z CAMs remain on track for an active thunderstorm environment with potential training cells capable of 1.75"+/hr rates and localized 2-3" totals. There remains continued latitudinal variance in the overall solution suite with another slight southward shift in the axis of heavy rainfall. The shortwave exiting the northern High Plains and expanding right entrance jet outflow dynamics will allow for strengthening of the low level jet; that initial WAA elevated cells should develop along a favorable west to east orientated line generally parallel to the mean steering flow to allow for training cells. However, the slightly stronger LLJ inflow and southward proximity to more unstable/moist air will allow for initially severe probably rotating updrafts in S MN to expand, grow up-scale to broader clusters and remain capable to intersect with rainfall of those initial WAA cells. However, stronger inflow and rotation of updrafts could allow for increased southward propagation as well,this may reduce some of that overlap maintaining situational uncertainty, though given the highly saturated ground condition and coordination with local forecast offices, have introduced a Slight Risk of Excessive rainfall across north-central WI to northeast WI. Downstream into the L.P. of Michigan, the overall convective complex will roll through the areas saturated by heavy rainfall yesterday, overall intensity should be reducing along with increasing forward speeds to limit rainfall totals. However, (near) record wet early spring, including spots of 2-4" yesterday, grounds are near or fully saturated that any rainfall will be converted to runoff and possible flash flooding. As such, the Slight Risk extends across Lake Michigan to encompass those areas most affected. Further south toward Chicagoland and across N IND, the 12z HRRR is bullish for convection breaking the cap across N IL later this evening with stronger convective cores expanding through interaction with the LLJ allowing for a favorable environment for 2-3" rainfall due to training. While recently dry over the last few days/week, the area also remains well above average in upper soil saturation values, AoA 60%, combined with larger urban centers prone to flash flooding including: Chicago, Gary, South Bend/Elkhart and Toledo, have expanded the Marginal Risk to account for this potential scenario. Gallina ~~~Prior Discussion~~~ A Marginal Risk for excessive rainfall was maintained for this period from eastern Minnesota to Lower Michigan. Although there was a modest decrease in the neighborhood probabilities for >1" totals, there still 20 to 40% across eastern Wisconsin and western Michigan as a formidable LLJ and increasing convergence within a progressing warm front could very well maximize the potential for heavier precip. Some rivers and streams across the region have ongoing minor flooding and any additional rainfall could speed up snow melt. Campbell/Kleebauer Day 2 Valid 12Z Wed Apr 15 2026 - 12Z Thu Apr 16 2026 ...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FROM THE TEXAS HILL COUNTRY TO THE UPPER MIDWEST/GREAT LAKES REGION... A developing upper jet coupling will likely aid in regional ascent with fairly generous instability axis situated from the Corn Belt to the southern Great Lakes and points south. Multiple areas of convection expected for this period from the Southern Plains to the Upper Midwest/Great Lakes region. The main area of focus will be over the Midwest where guidance is depicting several hours of cells producing up to 1.5 inches/hr rainfall rates from Iowa to western New York and SPC has identified this part of the country as having an Enhanced Risk for severe weather that includes the potential for damaging winds, very large hail and tornados. Meanwhile convection will fire up ahead of the dryline and approaching cold front across the Plains. The environment will be favorable for a few mesoscale convective systems to develop and the limited eastward progression will likely result in areas that have excessive rainfall leading to some instances of flash flooding. A Marginal Risk area span from the Texas Hill Country northeastward to the Midwest and western Great Lakes. SPC has highlighted much of the same area as having a Slight Risk for severe thunderstorms. Campbell/Kleebauer Day 3 Valid 12Z Wed Apr 15 2026 - 12Z Thu Apr 16 2026 ...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FROM TEXAS TO THE UPPER MIDWEST/GREAT LAKES REGION... The overall setup will be very similar for this period just shifted a bit to the east. SPC continues to have a Slight Risk for severe thunderstorms capable of producing damaging winds, large hail and a potential for tornadoes while WPC maintains a Marginal Risk for excessive rainfall from eastern Texas to the Midwest/Great Lakes region. Areal averages will generally be less than 1.5 inches but a few locations may exceed 1.75 inches. Guidance still has a fair amount of r spread on where some of the highest amounts will occur but consensus is hinting southeast Oklahoma to the Ozark mountains with a secondary focus from central Illinois to northwest Ohio. Campbell Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt