FOUS30 KWBC 220826 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 426 AM EDT Wed Jul 22 2026 Day 1 Valid 12Z Wed Jul 22 2026 - 12Z Thu Jul 23 2026 ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR SOUTHEASTERN VIRGINIA AND EXTREME NORTHEASTERN NORTH CAROLINA... ...Southeast... A strong but painfully slow moving cold front draped across Virginia today will continue to act as a train track along which numerous showers and thunderstorms will move throughout the day and into tonight. It's probable that many areas from western North Carolina through Raleigh and into the Hampton Roads area of southeast Virginia will see more time over the next 24 hours seeing moderate to heavy rainfall than dry time. The heaviest and most persistent rainfall will be into extreme northeastern North Carolina and much of southeastern Virginia southeast of Richmond today. The Hampton Roads metro appears to be the most at risk of the metro areas expected to be impacted by heavy rains today. It's likely areal averages in the Hampton Roads area will exceed 3 inches today through tonight. Given both the persistence of the heavy rain and urban concerns, the inherited Moderate Risk area will remain unchanged with this update, generally following the state line east from I-95 to the mouth of the Chesapeake. Elsewhere the Slight Risk area extending from northern Georgia to the Delmarva was shrunk both on the north and south sides with this update. The CAMs guidance are in good agreement on the corridor where heavy rain and flash flooding will be, increasing the confidence that a smaller latitudinal range will be covered by the heavy rain. As such, the southeastern corner of NC and all but northern SC were removed from the risk categories as the heaviest rains will stay north of those areas for today. They'll get their turn in the coming days. The length of the front will promote heavy rain development towards the west, and as such the Slight was expanded west into northeastern Alabama with this update, where the combination of the front and topography will both support areas of heavy rain and widely scattered instances of flash flooding. ...Intermountain West... The Slight Risk area covering an expansive area of the Intermountain West from southwestern Montana south through northwestern New Mexico was largely unchanged with this update. However, in coordination with ABQ/Albuquerque, NM forecast office, the Slight Risk area was expanded south along the AZ/NM state line with this update. Plentiful burn scars, relatively little amounts of rain it's taken in some areas to cause flash flooding, and many areas not seeing recent flooding at all are all contributing factors to the Slight Risk upgrade. Meanwhile further north, the heaviest rainfall totals will be tied to the topography in many areas from the Bitterroots through Yellowstone, much of Utah and western Colorado. With sufficient upper level forcing helping the storms to form and cause flash flooding, it's probable in many instances that any storms that start along the topography will move off the mountains towards the northeast, so lower elevation valleys in between also remain in the Slight Risk for flooding. ...Gulf Coast/Tropical Storm Bertha... T.S. Bertha will continue to struggle from strong northeasterly shear pulling nearly all of the significant associated rainfall south over the open waters of the Gulf. With little rain expected along the Gulf Coast, the inherited Marginal remains little changed. The Marginal mostly covers the fact that any significant tropical cyclone carries inordinate amounts of atmospheric moisture, even when being sheared. That moisture can easily support heavy rainfall, even if isolated, so the Marginal threat remains. Wegman Day 2 Valid 12Z Thu Jul 23 2026 - 12Z Fri Jul 24 2026 ...THERE'S A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF EASTERN NORTH CAROLINA... ...Southeast... A strong and very slow moving cold front draped across portions of the Mid-Atlantic on Wednesday makes only very slow progress through the day Thursday across far southern Virginia and northwestern North Carolina. A second day of intense rainfall in the form of seemingly endless trains of storms will impact much of the Carolinas on Thursday. The good news is the southward progress of the front on the order of about 50 miles or so will spare most of Virginia much heavy rainfall for yet another day. However, this means the heavy rain simply impacts areas further south across much of North Carolina and northern South Carolina. Unfortunately there looks to be some overlap in the heavy rainfall footprints from Wednesday into Thursday, particularly in northeastern North Carolina, likely extending from Norfolk south and east. Once again the heaviest rainfall amounts will likely concentrate along the coast. As such the Moderate Risk for this period was also unchanged, focused from I-95 east and from I-40 north and east. Further west, a similar situation remains as on Wednesday. Painfully slow southward movement means many of the same areas get hit with heavy rains again on Thursday as on Wednesday. The Slight Risk was expanded west along the front due to the large amounts of atmospheric moisture in place immediately ahead of the front. Many areas have PWATs above 2 inches. The Slight Risk area includes metros Birmingham, AL, Atlanta, and into Charlotte, NC. All 3 of these metros have some risk of training storms, with Charlotte the highest of those 3. ...Central Plains... A pair of nocturnal MCSs, one Wednesday night into Thursday morning, and a second much stronger one Thursday night into Friday, will impact portions of southeastern Nebraska, northeastern Kansas, and into small portions of Iowa and Missouri through the period. These back-to-back MCSs will sufficiently soak the soils such that the heavy rain with Thursday Night's MCS will cause widely scattered instances of flash flooding, especially where urban areas such as Lincoln, Topeka, St. Joseph, and possibly Omaha and Kansas City are impacted. The area of the Slight was adjusted, but remains little changed with this update. The isolated flash flooding threat represented by the Marginal extends well west of there through nearly all of Wyoming and Colorado. While the flooding threat diminishes considerably in these states compared with Wednesday, the leftover saturated soils and still likely formation of showers and storms will keep an isolated flash flooding threat going. ...Bertha/South Texas... Latest CAMs guidance are starting to come into agreement on a solution that keeps the circulation of Bertha intact over the northwestern Gulf before the westward moving storm moves inland in Texas near or south of Houston. As such, the persistent convection that continues to focus south/southwest of the center eventually impacts land areas, in this case in south Texas. A Marginal Risk covering much of South Texas was introduced with this update. It's likely that a Slight Risk upgrade will be needed with future updates, short of a northward jog in the guidance that kills off the rain much earlier, as the guidance had been showing in recent days. The area most likely to see that upgrade is around Corpus Christi through Victoria. Wegman Day 3 Valid 12Z Fri Jul 24 2026 - 12Z Sat Jul 25 2026 ..THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE SOUTHEAST AS WELL AS FOR MUCH OF MISSOURI... ...Southeast... The front that has been causing heavy rain across portions of the Southeast through Thursday continues on into Friday, though begins to weaken and in some areas lift back to the north as a warm front. Due to this weakening forcing, the rainfall forecast footprint over the Carolinas diminishes substantially (by about half) as compared with prior days' rains. While many areas continue to see periods of heavy rain, which may overlap with heavy rainfall from prior days, the much lower rainfall forecast over North Carolina did allow for the risk level to drop back into the Slight category for the Friday period. That said, any increase in rainfall, especially for areas hit hard on Wednesday and Thursday, could easily necessitate another upgrade to a Moderate for portions of eastern North Carolina with future updates. The rainfall forecast increases from prior days further west into northern Alabama and Georgia. The inherited Slight risk, as on past days, was expanded west. In this case, the expansion went all the way to the Mississippi state line with Alabama, as Alabama in particular looks to have its wettest day of the week on Friday. Considering prior days rains forecast for this same area, more favorable hydrology and further increases in expected rainfall in northern Alabama and Georgia could mean a Moderate Risk upgrade with future updates isn't entirely out of the question. Certainly eastern NC has a much higher chance of this happening. ...Missouri... An MCS over the area Friday morning diminishes in intensity with differential heating over the Plains and Ozarks on Friday. However, guidance is not in good agreement as to whether or not the rainfall dissipates entirely. Peak heating could provide enough instability that the convective organization changes, but not its coverage. Thus, A Slight Risk for a large portion of Missouri remains in place. Any rain will continue in this area into Friday night. ...Texas.. Regardless of whether Bertha does better at maintaining its intensity on Thursday, or if it dies earlier by taking a more northerly track, by Friday the rainfall associated with the storm will be long dissipated or diminished to nuisance showers. As such, all flooding risks directly associated with Bertha will be ended by Friday. Wegman Day 4 and Day 5 Valid 12Z Sat Jul 25 2026 - 12Z Mon Jul 27 2026 ...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FROM THE MID MISSISSIPPI VALLEY TO THE SOUTHEAST DAY 4 AND ACROSS PORTIONS OF THE WESTERN U.S. DAYS 4 AND 5... ...Mid Mississippi Valley to the Southeast... The overall trend in the overnight guidance was to shift the slow- moving surface front and associated axis of deeper moisture farther east and off of the Southeast Coast on Saturday, diminishing the threat for widespread additional heavy rains across the Carolinas. Therefore, the Slight Risk was removed from the eastern Carolinas. However, cannot rule out an isolated threat for localized heavy rains and an isolated flash flood threat. Therefore, the Marginal Risk was maintained for the Day 4 period from eastern North Carolina into the Southeast before notably drier air begins to spread across much of the region on Sunday. The Marginal Risk was also maintained farther northwest back across the Tennessee Valley into the mid Mississippi Valley. Some models, more notably the ECMWF and UKMET, show elevated storms that are expected to develop Friday night continuing to propagate southeast from the mid Mississippi into the Mid South, with deepening moisture and training storms raising the potential for heavy accumulations. As the associated mid level energy continues to drop southeast, there is the potential for at least locally heavy amounts and isolated flash flooding concerns as it interacts with lingering deep moisture from the Tennessee Valley into Alabama and Georgia on Saturday. ...Southwest to the northern Rockies... After a dropoff late in the week, the footprint for diurnal showers and storms is expected to expand once again by Saturday as high moisture anomalies (+2 sigma) return to parts of Arizona and New Mexico. This moisture along with mid-level energy moving around the southern periphery of the high will raise the threat for efficient-rainfall producers, raising flash flooding concerns across parts of the Southwest both days. This elevated moisture and enhanced forcing may support the need for an upgrade to a Slight Risk in future updates. Meanwhile deeper moisture and energy lifting along the northwest side of the high will extend the threat into parts of the northern Intermountain West and Rockies on Day 4, before moisture anomalies drop off on Day 5. Pereira 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 $$