Quantitative Precipitation Forecast
Issued by NWS
Issued by NWS
511 FOUS30 KWBC 200101 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 901 PM EDT Sat Apr 19 2025 Day 1 Valid 01Z Sun Apr 20 2025 - 12Z Sun Apr 20 2025 ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FROM NORTH- CENTRAL TEXAS THROUGH NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS... ...0100Z Update... Changes made to the Day 1 ERO, most notably the Slight and Moderate Risk areas, were based on the more recent HRRR and WoFS trends this evening. In particular, given the mid-upper trough amplification over the southern Rockies-High Plains, the orientation of both the Moderate and Slight Risk areas, particularly the western edges, were tilted more N-S. Again this was based in particular over the latest several HRRR runs (21/22/23Z), along with recent WoFS runs. Hurley ...Previous Discussion... A narrow corridor of 4 to 6+ inches of rainfall likely today across southern Missouri to North-central Texas as thunderstorms train and backbuild along a slow moving/stalled frontal boundary. There has been a consistent and persistent westward trend of the placement of the heaviest rainfall both in the model runs and the deterministic WPC QPF. Once again the risk areas were expanded south and west. The Moderate Risk spans from north-central Texas to the Missouri Ozarks; which had a minor reduction in coverage out of Illinois given the decrease in QPF from the Mid-Mississippi Valley to Ohio. The Slight Risk was also reduced over parts of Illinois and Indiana while extended further into central Texas. The Marginal was trimmed southward across Illinois, Indiana and Ohio while adjusted westward of west-central Texas. On the north side the cold, dry northeasterly flow will be weakening while in the warm sector there will be an ever increasing supply of hot and humid air straight out of the Gulf being advected northward on up to 50 kt winds across Texas and into the frontal interface from north Texas through Oklahoma and Missouri. An upper low ejecting from the mountains into this hot, moist airmass will lead to robust cyclogenesis over Oklahoma by Sunday morning. Campbell Day 2 Valid 12Z Sun Apr 20 2025 - 12Z Mon Apr 21 2025 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE CENTRAL AND SOUTHERN PLAINS INTO THE MIDDLE AND LOWER MISSISSIPPI VALLEY... ...2030z Update... Expanded the Marginal risk a bit based on the new guidance (largely the 12z HREF), both along the backside of the low (central KS/OK) and into more of the Southern Plains and Lower MS Valley (Middle and Upper TX Coast into the Ark-La-Tex) farther south along the progressing front. Some of the highest probabilities for significant rainfall are located across the southern portions of the Marginal risk (12z HREF 3" and 5" exceedance probabilities for 40-km neighborhood of 20-90% and 10-50%, respectively). These probabilities are likely overexaggerated, as there is quite remarkable spatial agreement among ALL of the HREF in one particular spot (north of Houston) which is inflating the probabilities. Nonetheless, the Marginal certainly warranted expansion, and a Slight risk introduction may be necessary with subsequent updates (as corresponding FFGs are quite high, between 3.0-5.0" for this portion of TX). Churchill ...Previous Discussion... The system responsible for the scattered to widespread heavy/excessive rainfall on Saturday will begin to accelerate to the northeast as the upper trough begins to fill. Rainfall amounts should not rival amounts that are expected on Saturday, but additional rainfall on top recently flooded areas remains a potential concern. General model consensus shows a broad footprint of up to 1.25 inches with isolated maximums of 1.5 to 2+ inches anywhere from eastern Nebraska to southern Minnesota and Wisconsin. The exact location of the heaviest amounts has the greatest uncertainty. A Marginal Risk is in place for the Middle and Lower Mississippi Valley and eastern portions of the Central Plains. These areas are north and west of the most sensitive areas of the Mississippi/Ohio River Valleys where streamflows remain high after recent flooding. However, some rain atop recently flooded areas, and runoff from other areas into these rivers, could exacerbate ongoing flooding issues in some areas, so continue to monitor. Campbell/Bann Day 3 Valid 12Z Mon Apr 21 2025 - 12Z Tue Apr 22 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Churchill/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