FOUS30 KWBC 110032 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 832 PM EDT Sun May 10 2026 Day 1 Valid 01Z Mon May 11 2026 - 12Z Mon May 11 2026 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF CENTRAL AND NORTH TEXAS... ...21Z Update... Issued a special (non-scheduled) update to the Day 1 ERO, based on the latest observational and HRRR trends, along with the newly- arriving 18Z HREF QPF exceedance probabilities. Per collaboration with WFO EWX, we opted to pull the southern portion of the Slight risk a bit farther south over the Lower TX Triangle, encompassing a little bit more of South-Central TX. Strong diurnal heating across this region downstream from the dryline (west) and main surface front (N-NW) is continuing to boost mixed-layer CAPEs, which are now running ~3000-3500 J/Kg per the SPC mesoanalysis. Meanwhile, TPWs are expected to climb above normal for a while this evening/overnight, nearing 1.75". Given the thermodynamic environment in place, rainfall rates of 2-3 in/hr will be plausible later this evening and overnight (esp 02-06Z), as the Slight Risk area sees more upscale growth in concert with the DPVA/deep-layer ascent ahead of the shortwave currently across eastern NM. Latest CSU UFVS-verified First Guess fields support the expansion of the Slight Risk. Elsewhere, have trimmed the Marginal Risk area across much of OK (now behind the front/increasing low-level stability), while also expanding across central-eastern AR, SW TN, and into much of central-northern MS. This expansion was also due to the growing short-range CAM consensus, along with the 18Z HREF probabilistic suite. For additional information regarding these areas now under the Marginal Risk, please refer to the latest mesoscale precipitation discussion, or MPD #167. Hurley ...16Z Update... The Slight Risk area was expanded a bit with this update, mostly towards the south but also to include the rest of the DFW Metroplex. Clusters of storms are expected to develop this afternoon, likely as a continuation of the showers and storms ongoing currently over Oklahoma, but developing further south into Texas. Much of the convective activity is expected to congeal south and west of the Metroplex, but urban concerns and some expected development over the Metroplex still heighten the flash flooding risk into the lower-end Slight category. Meanwhile, while convection will be more numerous and strong further south and west, less urban development may help to mitigate the flash flooding threat a bit. By late evening, around 03Z/10pm CDT or so, the convection is expected to have organized into a mostly single line of storms that will progressively shift southeast towards the Gulf. This should greatly mitigate the flash flooding threat by that point and beyond. Thus, the flash flooding threat is greatest in the late afternoon and evening while the storms are still organizing and therefore have more chaotic and slow forward motions. Wegman Day 2 Valid 12Z Mon May 11 2026 - 12Z Tue May 12 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR THE CENTRAL GULF COAST... ...18Z Update... A Marginal Risk of excessive rainfall was introduced for the central Gulf Coast with this update. A strong cold front pushing south out of the interior U.S. will interact with still sufficient Gulf moisture (PWATs between 1.5 and 1.75 inches) along the coast to force a renewed round of convection ahead of the front, which may also interact with the sea breeze. Corfidi vectors suggest storm movement will be fast towards the east, so backbuilding potential appears low. However, this area was hard-hit with heavy rain totaling over 3 inches in several areas of southeast Louisiana, with totals up to 2 inches across much of the rest of the Marginal Risk area just yesterday. Thus, while the area will be recovering today through tomorrow morning, expect that any heavy rainfall of meaningful duration may still lead to an instance of flash flooding or 2, especially in the urban areas within the Marginal Risk. Wegman Day 3 Valid 12Z Tue May 12 2026 - 12Z Wed May 13 2026 The probability of rainfall exceeding flash flood guidance is less than five percent. Wegman 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