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AGUS74 KWCO 121141
HMDNWC

National Hydrologic Discussion - EXPERIMENTAL
NWS National Water Center - Tuscaloosa AL
700 AM CDT THU MAR 12 2026

.Update...
The Mariana Islands were removed from the FHO this morning as Tropical
Depression Nuri has dissipated and is no longer expected to pose a
significant flooding threat to the Mariana Islands.
Additionally, the large majority of the Limited impacts area on the FHO for
the Lower and Middle MS Valley into the OH Valley has been removed as the
heavy rainfall and flooding threat has ended. The only exceptions to this
include southern IN/IL where a Considerable impacts area (and surrounding
Limited) on the FHO continues (although slightly smaller) for ongoing river
flooding within the lower portions of the White River Basin, and across
southern MI, northern IN, northwest OH where the Limited impacts area
continues through this weekend for ongoing and forecast river flooding from
the recent rainfall. The Limited selection on the FHO across the Northeast
was made smaller (confined more to where there is a remaining snowpack),
but continues for flooding concerns regarding recent rainfall and snow melt
through this weekend with a renewed threat early next week. No changes to
the considerable flood messaging in HI through Saturday.

//JEC

Previous Discussion as Follows:

...Considerable river flooding is ongoing and forecast to continue this
week in the Ohio River Valley... Considerable flash flooding is possible in
Hawaii through early weekend... Flash, urban, small stream, and river
flooding are expected tonight from East Texas through the Lower and Middle
Mississippi Valley... Small stream and river flooding are possible due to a
combination of rainfall and snowmelt through the weekend in the
Northeast... Isolated river flooding is expected to continue through Friday
over Southern Michigan, Northern Indiana, and Northeast Ohio through
Friday... Isolated minor river flooding is forecast in Western Washington
and Oregon... Flash and small stream flooding possible for the Mariana
Islands through Friday...

.Ohio River Valley...
Considerable river flooding continues across the White River and East Fork
White River  following recent heavy rainfall across those basins.
Additional rainfall of 1 - 2" though tonight is expected to result in
isolated flash and urban flooding across the already saturated region. The
additional rainfall may slightly prolong the ongoing flooding.

.Hawaii...
Considerable flash and urban flooding threat is expected to continue into
the weekend as heavy rainfall impacts the islands. Landslides will also be
possible in areas with steep terrain.

.East Texas through the Lower and Middle Mississippi Valley...
Multiple rounds of convective rainfall will bring the potential for flash,
urban, and small stream flooding through the nighttime hours. Widespread  1
- 2" of rainfall has already fallen this morning over eastern Texas,
northern Louisiana, and much of southern and eastern Arkansas this morning
with local values up to 3", resulting in wet to near saturated soil
conditions. Additional precipitation (1 - 3", locally higher) is expected
to develop and move east across this area and into the Southeastern US
through the day, increasing the potential of flooding over the region. Much
of the soils east of the previously mentioned morning precip is relatively
dry, with the exception of northern Mississippi and Alabama, which received
precipitation within the last 5 days, are around 50% and will initially
have soil capacity to mitigate widespread impacts. Given the convective
nature, the potential that the available soil capacity will become quickly
overwhelmed locally is high. Additionally, multiple rounds of heavy rain
could result in locally significant flooding at times, especially as we
move through the evening into the nighttime hours.

The National Water Model (NWM) Short Range Forecast (SRF) continues to
indicate the potential for flooding in eastern Texas, northern Louisiana,
into northern Alabama and central Tennessee, with high probabilities of
Rapid Onset Flooding, especially over north-central Mississippi. Given that
northern Mississippi has a high probability, with the high-water arrival
time late afternoon and early evening, confidence in the potential for
flooding impacts is high.

.Northeast...
Warmer temperatures over the next few days will melt out much of the
snowpack across the northeast. Snowmelt combined with 1 - 1.5" of rainfall
today and tomorrow will likely result in small stream and river rises,
including river flooding. This continued thaw may also start to break up
river ice, resulting in isolated break-up ice jams, particularly on
northern rivers that have built up thick ice over the last few weeks. Snow
water equivalent (SWE) amounts of 6 - 10" (locally higher) remain in place
across NY and southern New England (SNODAS). MMEFS ensemble guidance
continues to highlight the potential for minor to isolated moderate river
flooding at several locations across the region late this week.

.Southern Michigan, Northern Indiana, and Northwest Ohio...
Isolated minor to moderate river flooding is forecast to continue through
the week after recent heavy rainfall. Light rainfall is ongoing however,
the remaining totals should be relatively modest and have minimal impact on
ongoing recessions.

.Western Washington and Oregon...
An atmospheric river event will bring multiple rounds of moderate to heavy
rainfall into the Pacific Northwest through the week, causing concern for
isolated minor/moderate river flooding. River forecasts and the NWM suggest
a series of river responses beginning Thursday and continuing through
Saturday and again early next week.

.Mariana Islands...
Tropical rainfall will bring the potential for flash and small stream
flooding to Saipan and Tinian through Friday afternoon.

//GKendrick

Additional National Water Center products are available at
www.weather.gov/owp/operations

$$