204
AGUS74 KWCO 181511
HMDNWC

National Hydrologic Discussion - EXPERIMENTAL
NWS National Water Center - Tuscaloosa AL
1015 AM CDT FRI APR 18 2025

.Synopsis...
Heavy rainfall across the Southern Plains into the Mississippi and Ohio
Valleys... Urban and small stream flooding possible in Puerto Rico... River
flooding continues in the Lower Ohio and Mississippi Valleys... Flash
flooding possible in American Samoa...

.Discussion...

.Southern Plains into the Mississippi and Ohio Valleys...
Precipitation through day 3 (Sun) with totals of 1 - 4", locally higher,
(WPC QPF) may lead to flash, urban, small stream and river flooding from
northeast TX through OK and MO to the Ohio Valley. The highest chance of
strong thunderstorms and heavy rain are forecast for day 2 (Sat).
Currently, deep layer soils, 0 - 100 cm, are dry to wet but not saturated
(40 - 65%, NASA SPoRT) while streamflows are running normal to above normal
(USGS) suggesting there is infiltration capacity available, at least
initially. This system could bring a chance of encroachment upon previously
impacted rivers which are still elevated or in flood. Minor to isolated
moderate river flooding is possible with this system (MMEFS).

Finally, on days 5 - 7 (Tue - Thu) there will be a renewed round of
precipitation in areas of TX, OK, and the Lower Mississippi Valley but
uncertainty remains as to the magnitude and areal coverage of impacts.

.Puerto Rico...
Heavy rainfall bringing the potential for urban and small stream flooding
continues thru day 3 (Sun). There is also a chance for isolated mudslides
in areas of steep terrain.

.Lower Ohio and Mississippi Valleys...
Minor, moderate, and major river flooding continues in the Lower Ohio
Valley to Lower Mississippi Valley Basins as a result of the recent
historic rainfall. While most of the rivers and their tributaries have
reached crest, lower portions of the Mississippi River are forecast to
remain in flood stage through at least next week due to water routing
downstream.

Another system, bringing the potential for heavy rainfall and renewed river
rises in portions of the same area, arrives today through day 3 (Sun).
Overall, impacts are ongoing and these regions remain vulnerable to any new
rainfall.

American Samoa...
Heavy rainfall brings the potential for flash flooding this weekend.

//Kirkpatrick



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