FOUS30 KWBC 141941 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 341 PM EDT Tue Apr 14 2026 Day 1 Valid 16Z Tue Apr 14 2026 - 12Z Wed Apr 15 2026 ...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL ACROSS THE CENTRAL L.P. OF MICHIGAN,SOUTHEAST WISCONSIN, AND THE OHIO VALLEY... ... Ohio Valley... 16Z Update: The Slight Risk for Excessive Rainfall was expanded farther south to include central Illinois to central Indiana.Radar and surface observations show an outflow boundary lingering across the region from early morning showers and thunderstorms that may be a focal point for locally heavy rainfall this afternoon and evening. The RRFS and ARW model camps in particular are highlighting this region with QPF maxima in the 2-5 inch range. High seasonable PWATS and abundant instability also support the potential for high hourly rainfall rates. ...Wisconsin and Michigan... 16z Update: The forecast continues to support the risk for flash flooding as storms are expected to form along a stationary boundary over Wisconsin and then congeal into a line of storms that progresses southeastward into Michigan. The low level jet will transport moisture orthogonal to a stationary boundary across the region with the training of storms possible. Most of the area remains at near or above record spring rainfall and soils are fairly saturated. Cells capable of 1.5-2"/hr rates and localized totals of 2-3+" suggest the placement of a Slight Risk of Excessive Rainfall from southern Wisconsin to eastern Michigan. ...Previous Discussion... A Slight Risk for excessive rainfall remains in effect for portions of the Great Lakes region. A shortwave/vorticity center lifting out over the mean ridge in the Great Lakes region will drive stronger confluence of the low level jet across Iowa to trigger another round of strong to severe thunderstorms Tuesday evening. Overall deep layer steering flow and fairly orthogonal ascent over boundary should help to focus a similar west to east (WNW to ENE) oriented axis of training thunderstorms. Upper-level dual jet couplet will further enhance up-scale growth to a broader complex to maintain through the overnight period. Most of the area remains at near or above record spring rainfall and soils are fairly saturated, so with cells capable of 1.5-2"/hr rates and localized totals of 2-3+" suggest the placement of a Slight Risk of Excessive Rainfall across portions of eastern WI and central MI (along and north of I-94). ... Lower Trans-Pecos/Big Bend... 16 Update: Latest model guidance indicates a higher QPF maxima across the Lower Trans-Pecos region into the Big Bend as storms fire along the dry line in presence of a seasonally moist environment. HREF 24 hour QPF neighborhood probabilities are around 50-70% for 2 inches and 10-20% probabilities for 3 hour QPF exceeding flash flood guidance. A Marginal Risk was maintained, but this area will be a focus for locally heavy rainfall. ...Oklahoma and Kansas... 16z Update: Another targeted area for heavy rainfall will be span south of the Norman area, northeastward into the Tulsa metro and southern Kansas. Hi-res guidance indicates multiple rounds of storms could traverse this region as storms fire along the dry line boundary and south of a stationary front in Kansas. HREF 24 hour QPF probabilities exceeding 2 inches are fairly high (50-70%) and 20-40% for exceeding 3 inches. ...Previous Discussion... A steady stream of PW values of 1.25 to 1.5 inches will be advecting northward through the Southern/Central Plains nearly parallel to the dryline. This will be conducive for slow storm motion with locally heavy rainfall. Consensus suggests 3 to 4 inches possible within the isolated cells. The Marginal Risk area is connected to the area of concern over the Great Lakes and just note the coverage will decrease northward along the dry-line. Campbell/Wilder Day 2 Valid 12Z 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.. The surface to mid-level environment remains very similar to the past couple of days with a stark dry line extending from the Pecos River Valley across the Southern Plains into the Upper Mississippi Valley. A stationary front will continue to align west to east from Illinois to New York and serve as a mechanism for heavy rainfall potential. The longwave trough will finally be making progress toward the Central Plains and the deep layer moisture axis and instability shifts slightly eastward. An upgrade to a Slight Risk for Excessive Rainfall was added across southern Wisconsin and Michigan. Across the northern Ohio Valley, northern Illinois, Indiana, and Ohio were included in the risk area. A persistence forecast worked well here where instability, plentiful moisture near the surface (PWATS near or exceeding 1.5 inches), and a nearby stationary boundary and weak area of low pressure will help create an environment capable of producing heavy rainfall. WPC QPF indicates 1-3 inches of rain over the same regions that have have seen rounds of heavy rainfall over the past couple of days. The flash flood guidance, meanwhile, has lowered to a half an inch to an inch. Another consideration was the flash flood sensitivity for urban areas such as Milwaukee, Chicago, and Detroit. The Slight Risk does extend southward across northern Illinois and Indiana to account for uncertainty on storm track and the spread of 2 inch HREF 24 hr QPF neighborhood probability. ...Eastern Oklahoma and the Ozarks... Similar to the past couple of days, afternoon storms are likely to form and trek from the southwest to northeast ahead of the longwave trough moving into the Central Plains. Eastern Oklahoma into the Ozarks will be in the right entrance of the jet streak, which will help provide lift. At the surface, high PWATS and surface instability will once again prime the atmosphere for hourly rainfall rates of an inch/hr. QPF guidance does show a maximum of 1-2 inches across the region, but model guidance shows little to no probability for accumulations exceeding 2 inches. Therefore, a Marginal Risk is maintained for the risk area. Additionally, the more flash flood prone Ozark mountain range is relatively dry. ...Northeast... A Marginal Risk for Excessive Rainfall was expanded eastward across New York State to Connecticut. Moisture transport will increase across the east as the longwave trough shifts eastward into the center of the country. Additionally, weak areas of low pressure will ride along a stationary boundary across the Northeast that will help funnel moisture across the area. 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. Wilder Day 3 Valid 12Z Thu Apr 16 2026 - 12Z Fri Apr 17 2026 The probability of rainfall exceeding flash flooding guidance is less than 5 percent. Wilder 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