754
AGUS74 KWCO 071521
HMDNWC

National Hydrologic Discussion - EXPERIMENTAL
NWS National Water Center - Tuscaloosa AL
1015 AM CDT SAT JUN 7 2025

.Synopsis...
Locally considerable flash and river flooding remains possible across the
Southern Plains into the Ozarks... Isolated flooding responses possible in
the Lower Mississippi Valley into the Southeast, Northeast, and the Ohio
River Valley...

.Southern Plains into the Ozarks...
An active weather pattern throughout the region continues to bring the
threat of locally considerable flash and urban flooding, along with
possible river flooding through the weekend. Surface soils (0 - 10cm RSM,
NASA SPoRT) are nearly saturated (85%+)  across much of the northern half
of OK and into the Ozarks. Rivers and streams are still running above the
75th percentile for historic flows, with many running above the 90th
percentile, keeping the region vulnerable to any new rainfall. Day 2 (Sun)
is forecast to have the highest rainfall amounts concentrated around
southern OK into northern TX. These areas may be somewhat resilient (40 -
60% RSM) to the initial rounds of rainfall, but may be quickly overwhelmed
if higher rainfall rates were to materialize. New and renewed flooding is
possible on area streams and creeks which were recently impacted from
recent rainfall.

Multiple days of scattered showers and thunderstorms centralized around the
Southern Plains next week, days 3 - 7 (Mon - Fri), may delay recessions and
keep conditions primed for flooding. The NWM Medium Range Forecast is
showing some areas` Highwater Arrival Timing over the next 3 - 7 days with
some of the larger mainstem rivers potentially continuing into next
weekend. Annual exceedance probabilities are generally at 50 - 20% which
suggest that some out-of-bank responses are possible, particularly if
training of showers and thunderstorms were to occur.  Due to the convective
nature of this pattern and some divergent model resolutions, confidence in
the exact timing, location, and magnitude is low.

Considerable river flooding continues across the Lower Middle Arkansas,
Upper Neosho, and Upper Osage basins in KS after recent heavy rainfall.
Most rivers have crested or are currently cresting in moderate flood
however, flooding is expected to continue through the weekend. River
ensembles are starting to indicate the potential for river rises across the
region including the Trinity, Sabine, and Neches river basins in TX and
tributaries of the Red River in OK/TX including minor to moderate river
flooding over the next 7 days.

.Lower Mississippi Valley into the Southeast...
Isolated flash flooding may be possible across the region through day 3
(Mon). Recent rainfall has left top soils across the region wet but not
saturated, providing some additional infiltration capacity thus leading to
a reduction of the overall flood threat. However, periods of higher
rainfall rates could still lead to some scattered flooding impacts,
especially in urban areas with poor drainage.

.Northeast...
Isolated flash, urban, and small stream flooding remains possible across
portions of New England through today due to continued rounds of heavy
rainfall (1 - 3", locally higher). Soils are moistening and streamflows are
generally above normal suggesting that the area is vulnerable to runoff and
out-of-bank flows on smaller streams if heavy or repeating rounds of
rainfall were to materialize. The HRRR-forced NWM signals are somewhat
subdued as the event is wrapping up but basins near the Catskill Mountains
(NY) are still signaling up to 50% probability of rapid-onset flooding.
Urban and flash flooding remain the focus for flooding with this event
however, rapid-rises on small streams and creeks remains a possibility due
to terrain enhancement.

.Ohio River Valley...
Scattered thunderstorms may generate isolated flash and urban flooding in
the Ohio River Valley into portions of the Central Appalachians through day
2 (Sun). Some embedded higher rainfall rates may elicit flooding responses
across the region as enhanced flows efficiently route runoff into swollen
streams from recent heavy rainfall (1 - 3", 48 hour MRMS). Flooding will
likely be confined to urban areas and in the steeper terrain of WV. Minor
flooding is ongoing or forecast to crest over the weekend.

//JAC

$$