####018005515#### AGUS74 KWCO 101522 HMDNWC National Hydrologic Discussion - EXPERIMENTAL NWS National Water Center - Tuscaloosa AL 1015 AM CDT FRI MAY 10 2024 .Synopsis... Major river flooding impacts ongoing in East Texas... Lingering flash flooding impacts in the Lower Ohio and Tennessee River Valleys... Potential for flooding impacts across the Lower Mississippi Valley and Southeast, Puerto Rico, Hawaii and American Samoa... Ice jam-induced flooding possible in Alaska... Ongoing river flooding in the Upper Midwest and Mid-Mississippi Valley... Coastal flooding possible on the Mid-Atlantic coast... .Discussion... .East Texas... Prolonged major river flooding impacts along the Lower Trinity and Lower Neches, as well as isolated moderate river flooding impacts, are ongoing across portions of the region. The Trinity at Moss Bluff has crested and is forecast to fall below major flood stage by the end of day 1 (Fri) and then continue to fall below moderate flood stage early next week. Both the Trinity at Liberty and the Neches at Saltwater Barrier have also crested, but will remain in major flood stage into next week. While drier conditions have provided some relief to these basins, the wet soils for all column depths have not had an appreciable amount of time to recover and streamflows are still much above climatological normal (USGS). As such, additional rainfall on days 3 - 4 (Sun - Mon), will likely result in immediate runoff into very sensitive rivers, increasing the potential for additional or renewed river flooding impacts, especially in smaller, more responsive basins. Localized flash and urban impacts cannot be ruled out if higher rainfall rates were to materialize or if training of showers and thunderstorms were to occur. .Lower Ohio and Tennessee River Valleys... Lingering river flooding will persist into the weekend, with most rivers already having crested. Additionally, the Red River near Port Royal (TN) reached major flood stage yesterday and will continue to recede through day 1 (Fri). Additional rainfall on days 4 - 5 (Mon - Tue) and again late in the period may bring renewed flooding impacts to the region. .Lower Mississippi Valley and Southeast... Lingering moderate to heavy rainfall will continue to push eastward and offshore this morning and impact portions of southern GA and northern FL. Current radar imagery shows this area of rainfall being rather progressive, but some isolated instances of flash and urban flooding will be possible. Additional redevelopment is forecast across portions of southern GA and northern FL this afternoon, which may bring localized flooding impacts back to these areas. Much of the region is forecast to receive additional rounds of rainfall on days 3 - 5 (Sun - Tue), bringing the potential for new and renewed flooding impacts. The heaviest rainfall totals are currently forecast on days 4 - 5 (Mon - Tue) along the central and eastern Gulf Coast, and inland across the FL Panhandle/southern GA. Given the extended timeframe and variations in the placement of heaviest QPF, confidence in any potential hydrologic impacts remain low at this time. .Puerto Rico Urban and small stream flooding impacts, along with the chance for isolated flash flooding, will remain possible through day 2 (Sat). Wet soil conditions and locally elevated streamflows will increase the potential for hydrologic impacts, including mudslides in areas of steep terrain. .Hawaii... Flash and urban flooding impacts are possible through early on day 2 (Sat) as locally heavy rainfall falls on the islands. .American Samoa... Isolated flash and urban flooding impacts will be possible through today, with landslides also possible in areas of steep terrain. .Alaska... Various small ice jams in the Kuskokwim Delta between Akiak and Napakiak are causing high water In Tuluksak. As these jams release, high water and potential flooding impacts will be possible in Akiak, Kwethluk, and Bethel. Looking north to the Yukon River, an ice jam front is also expected to impact the community of Circle. Ice jam breakups and formations are expected to continue along this breakup front as it makes its way down the Yukon River. Ice jams and breakup fronts can evolve rapidly, so refer to the local forecast offices for up-to-date information. .Central Montana... Warming temperatures will bring snowmelt to the mountain ranges of central Montana and may lead to small stream flooding and rises on area rivers. In addition, local showers on day 2 (Sat) may further exacerbate flooding impacts. .Mid-Atlantic... Increasing onshore flow will bring coastal flooding impacts to the Mid-Atlantic coast through midday on day 2 (Sat). Please refer to the local offices for additional information. .Upper Midwest and Mid-Mississippi Valley... Minor to moderate river flooding is ongoing and forecast across IA, MO, and western IL. Many locations are still rising, with crests expected through the weekend as the elevated flows route downstream. With no significant rainfall expected over the next week, recessions will continue unimpeded though, some light to moderate rainfall on days 4 and 5 (Mon and Tue) may slow recessions. //Whisnant $$