Hydrometeorological Discussion
Issued by NWS Tuscaloosa, AL
Issued by NWS Tuscaloosa, AL
287 AGUS74 KWCO 301517 HMDNWC National Hydrologic Discussion - EXPERIMENTAL NWS National Water Center - Tuscaloosa AL 10:15 AM CDT MON JUN 30 2025 .Synopsis... River flooding to persist through at least midweek across the Central Plains and Mid to Upper Mississippi Valley... Flooding possible through midweek along the Gulf Coast... Flash flooding possible through this week in the Southwest into the Southern Plains... Localized flash and urban flooding possible in the Mid-Atlantic... Flooding potential continues across the Mariana Islands... .Central Plains and Mid to Upper Mississippi Valley... Scattered minor to isolated moderate river flooding is ongoing and forecast across portions of MO, NE, IA, MN, and WI through at least midweek following repeated rounds of heavy rainfall over the past several days. In addition to ongoing river flooding, slow moving precipitation last night and scattered convection leading to heavy rainfall today, could bring the potential for flash flooding through today, as it moves across the Middle/Upper Mississippi valleys. .Gulf Coast... Periods of heavy rainfall may generate isolated flash and urban flooding impacts along the I-10 corridor from coastal MS through the FL Big Bend region through midweek. For most of the region, current soil moisture values are near normal (35 - 55% RSM, 0 - 10 cm NASA SPoRT) and streamflow values are near to below normal for this time of year (USGS), which suggests infiltration capacity initially. The exception to this is the FL Big Bend region, where wetter soils (RSM 70%, NASA SPoRT) are in place following recent rainfall, which indicates slightly greater hydrologic sensitivity to rainfall. As of now, the primary threat is urban flooding given the dense urban infrastructure along the I-10 corridor. Both the GFS and NBM-forced NWM are indicating little to no responses, as the heaviest QPF remains off of the coast. Most flooding impacts should be from isolated convection. .Southwest into the Southern Plains... Sporadic convection due to abundant moisture and remnants of Tropical Storm Barry, may lead to multiple rounds of heavy showers through day 7 (Sun). With heavier totals possibly moving over the Sacramento Mountains in NM, flash and arroyo flooding are possible through the week. In TX, flash flooding is not expected at this time, but ponding of water in low lying areas may be a concern. In general, recently burned areas will be particularly vulnerable to flash flooding. .Mid-Atlantic... Progressive storms embedded with unstable convection may introduce the threat of localized flash flooding on day 2 (Tue). The NWM is showing rapid onset flooding probability (ROF) signals in the 25 - 75% range in areas such as Washington D.C., MD, eastern WV, northern VA, and southern PA. There is a chance these storms could stall which would lead to heavy downpours. Steep terrain in the Appalachian mountains and urban areas are particularly vulnerable to the threat of prolonged and heavy showers. .Mariana Islands... The potential for flash flooding will continue through Tuesday afternoon (local time) as monsoonal showers and storms persist across the islands. //DLeisure $$