129 FOUS30 KWBC 151550 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 1150 AM EDT Wed Apr 15 2026 Day 1 Valid 16Z Wed Apr 15 2026 - 12Z Thu Apr 16 2026 ...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR THE GREAT LAKES AND NORTHERN OHIO VALLEY.. ...Great Lakes and Ohio Valley... 16Z Update: Another round of convection anticipated this afternoon and evening with the relative QPF maxima likely occurring over similar areas that were impacted the past 24 hrs. Antecedent conditions favor a more sensitive soil moisture composition along with remnant elevated streamflows situated across the area from eastern IA through northern IL and southern WI. This zone over into lower MI is the most sensitive region for the period in question leading to a bit more of a proactive approach in the forecast SLGT risk. The inherited risk was expanded a bit further north across the aforementioned areas, encompassing now all of southern WI and northern IL as the next wave of convection will likely refire in proximity to the quasi-stationary front and point south where instability is greatest along with a robust PWAT anomaly (95-99th percentile) given seasonal climatology. KDTX PWAT's were a primary signal for this characteristic this morning as their 1.14" PWATs came in squarely around a +3 deviation for the date, and this area isn't even in the more robust moisture anomaly when assessing the the latest NAEFS where further southwest is even more appreciable in its anomaly. 12z HREF blended mean QPF depicts a relatively solid 1-2" distribution with embedded maxima between 2-2.5" across the southern WI to northern IL area with a secondary maxima oriented from west-central IL up into southeast MI, bisecting northern IN in the process. Neighborhood probabilities of >2" are upwards of 50-80% within the two zones referenced with a general min around the Chicago metro. Considering the nature of convection and how small deviations in outflow propagation can play big parts in the forecast, felt it was necessary to maintain the major urban corridor of Chicago to cover for any uncertainty in how the convective scheme will play out this evening. The SLGT risk was expanded further southwest into IL to account for the trends in CAMs and with coordination from the Springfield, IL WFO where convection is already causing some 1-2" maxima to crop up prior to the update. Kleebauer ...Southern Plains, ArkLaTex to Ozarks... 16Z Update: Convection will refire along the dryline again later this afternoon with upscale growth anticipated after 00z as LLJ introduction will aid in multi-cell mergers and heavy rain prospects from southern MO down into north TX. Upper pattern to the west remains favorable for large scale ascent to occur across the Red River Basin of TX/OK, perhaps as far south as the I-20 corridor, to points northeast within eastern OK and neighboring AR to southern MO as the entire region settles within a developing jet couplet on the southern edge of a robust shortwave trough. Instability and deep moisture presence situated across all of the Southern Plains to Mid-Mississippi Valley is more than enough to constitute general convective properties with efficient rates between 1-3"/hr at peak intensity, represented very well by the latest HREF hourly probabilities for >1"/hr running between 25-60% over the entire area referenced above with low-end to modest probs (15-30%) for >2"/hr in a corridor between northwest AR down to southeastern OK. Antecedent conditions in these zones are still pretty dry with the 1/3/6 hr FFG parameters all sufficiently above 2.5" for each threshold. That said, urbanized areas will still see higher run off capabilities with a potential for localized flash flooding in the evening and overnight time frame. The overall meteorological premise for a flash flooding threat remains viable, but the antecedent hydrologic concerns are still relatively tame compared to areas much further north which leans towards a maintenance of the MRGL risk inherited with a chance on a targeted upgrade this evening pending convective output. Kleebauer ...Northeast... 16Z Update: Little change in the previous forecast with a widespread MRGL risk extending from western NY/PA over into parts of southern New England. HREF neighborhood probabilities are fairly robust for >1" (50-80%) across much of the above corridor with the highest probs for both >1" and >2" located downwind of Lake Erie. Urbanized zones will be the primary areas of interest across the Northeast U.S. which historically has been the root for most run off potential and localized flash flood prospects. With guidance maintaining run-to-run continuity, this was enough to keep what was previously forecast with only small modifications to align with the latest HREF blended mean QPF distribution. Kleebauer ..Previous Discussion.. Remnants of the storms across the Great Lakes may bring a round of showers and storms in the morning, followed by another round of heavier showers and thunderstorms in the afternoon. Model guidance shows a corridor of 1-1.5 inches rainfall with embedded higher amounts depending on the model. The relatively lower flash guidance across western Pennsylvania and the more urban footprint of areas such as Connecticut and New England also help confidence of expanding the Marginal eastward. Campbell/Wilder Day 2 Valid 12Z Thu Apr 16 2026 - 12Z Fri Apr 17 2026 The probability of rainfall exceeding flash flooding guidance is less than 5 percent. Campbell Day 3 Valid 12Z Fri Apr 17 2026 - 12Z Sat Apr 18 2026 ...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR NORTHERN MISSOURI, EASTERN IOWA AND NORTHWEST ILLINOIS... A band of weakening showers and thunderstorms will pass through the Ohio Valley with the lead shortwave trough. Meanwhile the long wave trough approaching the Midwest will have better large scale ascent and instability to yield better areal coverage of QPF with a more focused swath of higher amounts across Missouri to the Illinois/Wisconsin border. The previous Slight Risk area was positioned more over Iowa and Wisconsin, however the latest trends suggest a modest south/southeast adjustment to northern Missouri, eastern Iowa, northwest Illinois and extreme southwest Wisconsin. will be valid from northern Missouri to southwestern Wisconsin for 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