![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
Hydrometeorological Discussion
Issued by NWS Tuscaloosa, AL
Issued by NWS Tuscaloosa, AL
946 AGUS74 KWCO 271523 HMDNWC National Hydrologic Discussion - EXPERIMENTAL NWS National Water Center - Tuscaloosa AL 1015 AM CDT THU JUN 27 2024 .Synopsis... Additional rounds of rainfall in the Central Plains and the Upper and Middle Mississippi Valley... Flash flooding possible in the Four Corners region, Southeast, and Northeast... Snowmelt induced flooding continues in Alaska... .Discussion... .Central Plains and the Upper and Middle Mississippi Valley... Widespread moderate to major river flooding is ongoing and/or forecast across southeast SD, southern MN, and northern IA. Record flooding is ongoing and forecast along the Minnesota and Des Moines rivers. Much of the ongoing major river flooding is in recession. However, as the flood wave routes downstream and additional rainfall is forecast, flooding impacts on mainstem rivers, including the Mississippi and Missouri rivers, are still to come. An additional 1 - 3" of rain is expected through day 2 (Fri) over portions of the northern Plains into the Midwest. As soil is already saturated (70 - 90% RSM, 0 - 10 cm RSM, NASA SPoRT), any rain that falls within the Missouri and northern Mississippi basins, will most likely runoff into already swollen streams and rivers. Though this amount of rainfall will most likely not have a major impact, it will allow moderate to major river flooding to persist, and new localized flooding impacts can be expected. Over the Central Plains, up to 3" of rain is expected through tomorrow morning near the Kansas-Nebraska line. Though this may cause isolated instances of urban flooding, rural flash, and small stream flooding are not expected as soils in the area are rather dry (less than 50%, RSM, 0 - 10 cm RSM, NASA SPoRT), and streams are below normal (USGS). There is potential for locally heavy rainfall forecast day 5 (Mon) across MN and northern IA. This area will have some time to recover from ongoing impacts before this next event but will need to be monitored closely, given the vulnerable antecedent conditions. .Four Corners... Moisture will persist over the region throughout the week, particularly in parts of NM, AZ, and western CO, leading to locally heavy rainfall and the potential for flash flooding. Areas that receive multiple rounds of rainfall are more susceptible to flooding impacts as soils reach saturation. The highest flood threat is in areas with recent burn scars, slot canyons, dry washes, and regions where training and more persistent storms occur. .Northeast... Moderate to heavy rainfall on day 3 (Sat) will bring the potential for isolated flash and urban floodings to portions of the Adirondacks and northern New England. Soils are generally wet closest to the Canadian border (65 - 75% RSM, 0 - 10 cm NASA SPoRT), making this region more susceptible to flash flooding. Though areas to the south are somewhat drier, if heavy rainfall occurs, soils will not take long to become near saturated, increasing the threat of flooding. The latest GFS-forced NWM MRF has started to indicate the potential of rapid onset flooding over the Adirondacks and northeast along the Canadian border. These signals are generally for lower-order streams, where AEPs are generally around 20%. This suggests that though streams may see a rapid rise, flows will likely not significantly increase, especially on higher-order streams. .Southeast... Daily scattered precipitation through the weekend will bring the potential for isolated flash and urban flooding to the region, with the highest potential being over southern LA/MS though FL/GA/SC. This area is generally dry, suggesting that flooding impacts will generally be mitigated and rainfall will be beneficial. However, given how soils have reacted to recent rainfall over AL (NASA SPoRT), both urban and flash flooding is not out of the question if training occurs. .Alaska... Warming temperatures continue to cause snow and ice melt at high elevations, leading to rivers running high in areas across Southcentral AK. Minor flooding on the Chilkat River near Klukwan continues into early this week, with ample snow available to melt. Minor river flooding is expected on the Skwentna and Yentna Rivers through the week. Also, high water continues on the Nuyakuk River near Dillingham. //GKendrick $$