021 FOUS30 KWBC 020806 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 406 AM EDT Thu Apr 2 2026 Day 1 Valid 12Z Thu Apr 02 2026 - 12Z Fri Apr 03 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF NORTHERN ILLINOIS, WISCONSIN AND MICHIGAN... The primary area of interest for flash flooding will likely lie over far northern Chicago suburbs up into the Milwaukee metro due to the areal urban footprint and suggestion of heavier rainfall in the area, especially the second round of convection. Fortunately, rates are generally capped at 1-1.25"/hr at peak intensity with much of the CAMs hourly outputs closer to 0.5-1"/hr for the heaviest periods of impact. This lies right on the edge of any FFG exceedance, so the threat will be somewhat capped overall for a multitude of reasons. There will likely be two main rounds- the first in the morning hours followed by a most robust line during the afternoon when there will be more ample large scale forcing/instability as the surface cold front approaches from the West. Overall areal averages across the region will be in the 1-2 inch range with locally isolated higher amounts possible. Campbell/Kleebauer Day 2 Valid 12Z Fri Apr 03 2026 - 12Z Sat Apr 04 2026 ...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF THE SOUTHERN PLAINS INTO THE OZARKS REGION... Strong to severe thunderstorms along with embedded heavy rainfall will track across the Southern/Central Plains into the Mississippi Valley/Midwest during this period. Moisture (with PWs over the 90th, perhaps 95th percentile) and instability are likely to pool along and ahead of the associated cold front and produce widespread convection. Storms likely beginning in the afternoon are expected to get reinforced through the evening and night hours as a low level jet picks up ahead of the cold front. Given that some of this region has been drier, it will take awhile before there are substantial flash flood concerns. Some of the highest amounts/rates are likely to focus over parts of central and eastern Oklahoma down into the Red River Basin between the Texas and Oklahoma border. Consensus has areal averages of 1 to 3 inches while some of the hi-res guidance is hinting at isolated maximums of 4 to 7 inches. Slight Risk area spans from north-central Texas to southwest-southern Missouri. Campbell/Kleebauer Day 3 Valid 12Z Sat Apr 04 2026 - 12Z Sun Apr 05 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE CENTRAL AND EASTERN GREAT LAKES SOUTHWESTWARD TO CENTRAL TEXAS AND THE LOWER MISSISSIPPI RIVER VALLEY... Much of the convection that evolves across the Marginal Risk area on D3/Sat will depend on specific evolution of convective complexes that originate from the central/southern Plains on D2/Fri. Although those details are a bit uncertain at the time frame, general consensus is that one or two MCSs will traverse the Mississippi Valley/Mid-South early in the forecast period before convective redevelopment occurs upstream along a composite outflow/cold front during peak heating hours from central Texas to Mississippi. Areas of training are likely if this pattern holds, with initiating boundaries supporting deep convection eventually becoming more parallel to steering flow aloft. Portions of this region may require an upgrade to Slight in later outlook updates. Farther north, convective coverage is far less certain - particularly from Illinois to Ohio. Deeper convection south of these areas could disrupt inflow/instability and lead to a minimum in precipitation in these areas. Again - this regime is uncertain. The primary reason Marginal was maintained for D3 from Illinois eastward to New York State and West Virginia was soils/local sensitivity. Soils are wetter with eastern extent from prior rainfall and could still be sensitive to even moderate rainfall by D3/Sat in a few spots. Cook 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