FOUS30 KWBC 070810 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 410 AM EDT Thu May 7 2026 Day 1 Valid 12Z Thu May 07 2026 - 12Z Fri May 08 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM SOUTHERN ALABAMA AND THE FLORIDA PANHANDLE TO SOUTHERN GEORGIA... ...Gulf Coast/Southeast... While the overall coverage and intensity will likely be diminishing, showers and storms will remain ongoing with the potential for additional heavy amounts and flash flooding concerns beyond 12Z this morning. A Marginal Risk was maintained across portions of southern Alabama, the Florida Panhandle, and southern Georgia. A 40-50 kt southwesterly low level jet ahead of an approaching front will continue to support PWs around 2 inches, which along with favorable upper jet forcing will likely support the continuation of some storms with heavy rainfall rates well into the morning. Both the HREF and RRFS indicate that localized additional amounts of 1-2+ inches are likely. This is expected to occur mostly, if not entirely, within the first 6 hours of the period before the deepest moisture and the better forcing moves downstream. ...Rio Grande Valley... The Marginal Risk has been removed. While a weak surface low and approaching shortwave trough will support convective development over the mountains of Mexico, the majority of the models indicate that the bulk of the heavy rainfall will remain south of the international border. While an isolated heavy total remains possible, and the threat for flash flooding across South Texas is non-zero, the coverage is no longer expected to meet Marginal Risk criteria. Pereira Day 2 Valid 12Z Fri May 08 2026 - 12Z Sat May 09 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM SOUTH TEXAS GULF COAST THROUGH THE LOWER MISSISSIPPI VALLEY... The synoptic pattern on Friday will characterized by the return of deep moisture as a previously stalled front, lingering along the Gulf Coast begins to lift northward as a warm front. PWs are forecast to climb above 1.75 inches from South Texas through the lower Mississippi Valley, providing an ample reservoir for heavy rainfall. This moisture, along with an upper level low moving into West Texas and downstream shortwave energy/upper jet forcing, are expected to support numerous showers and storms with the potential for heavy rates. However, while the environment is expected to be favorable for numerous showers and storms to develop, confidence in the placement of the heaviest rainfall has diminished with this cycle, with significant model spread regarding where the most intense convective clusters will organize. Therefore, the Slight Risk that was previously carried from southeastern Texas through the lower Mississippi Valley has been removed for now. The reintroduction of a Slight Risk may be warranted in future updates, particularly farther southwest across South Texas closer to the ejecting upper low/shortwave, but predictability is too low to maintain the higher category. For now, will maintain a broad Marginal Risk extending from South Texas to southern Mississippi. Pereira Day 3 Valid 12Z Sat May 09 2026 - 12Z Sun May 10 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PARTS OF THE LOWER MISSISSIPPI VALLEY AND THE CENTRAL GULF COAST... The previously noted upper level low moving across southern Texas on Day 2 will continue to eject east, moving along the central Gulf Coast into the Southeast -- deamplifying as it becomes embedded within the base of a broad upper trough centered over the central- eastern U.S. Deep moisture remaining ahead of this wave and along a slow-moving boundary will continue to fuel shower and storm development capable of producing heavy rainfall. Similar to Day 2, confidence was lacking for any upgrades beyond a Marginal Risk. However, should the models start to move into better agreement, an upgrade may be warranted in future updates -- especially if the guidance begins to show a growing signal for heavy amounts across areas impacted by recent heavy rains. 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