815
AGUS74 KWCO 171510
HMDNWC

National Hydrologic Discussion - EXPERIMENTAL
NWS National Water Center - Tuscaloosa AL
1015 AM CDT SAT MAY 17 2025

.Synopsis...
Potential for isolated flash and small stream flooding in the Northeast...
Multiple days of rainfall, potential for flash and river flooding across
the Central Plains and Middle Mississippi Valley and Ohio River Valley...
Flash flooding threat continues for Puerto Rico and the USVI... Potential
for ice jam flooding in portions of Alaska...

.Northeast...
Isolated flash and small stream flooding is possible across portions of NY
into ME through day 2 (Sun). While antecedent conditions are generally
primed, fast storm motion and relatively low QPF totals should help limit
any significant flooding concerns. Still, isolated instances of flooding
can`t be ruled out, especially where higher rainfall rates develop.

.Central Plains and Middle Mississippi Valley...
Isolated flooding impacts are possible on days 2 - 4 (Sun - Tue) due to
multiple rounds of rainfall totaling 2 - 5", especially across portions of
MO and IL where the highest amounts are expected. Flash flooding due to
training and high rainfall rates appears to be the primary threat however,
river ensemble forecasts (HEFS) indicate some potential for minor and even
isolated moderate river flooding (30% chance of exceedance) in MO.
Antecedent conditions leading into this event are mostly dry, particularly
across the Plains where drought conditions remain in place (USDM), but
across southern portions of MO and IL, recent rainfall has increased soil
moisture and locally elevated streamflows. These wetter conditions may
increase flooding potential in the region, though widespread flooding is
not anticipated at this time.

.Ohio River Valley...
Flash and urban flooding, as well as minor river flooding, is possible on
days 3 - 5 (Mon - Wed) as periods of locally heavy rainfall affect the
region. At this time, daily rainfall amounts are generally expected to
remain below 2" and the placement of the highest daily amounts do not
overlap. The placement of the highest daily amounts will likely shift as we
approach this time period, and with convection expected, high rainfall
rates and training will again be the primary cause of any flash flooding
that occurs. Antecedent conditions are generally wet but not saturated,
except across much of TN, KY, and WV, where upper layer soil moisture is
nearing saturation, increasing the potential for enhanced runoff into area
streams and rivers, some of which are already elevated. Isolated minor
river flooding is ongoing or forecast in KY and river ensemble guidance
indicates additional river flooding is possible.

.Puerto Rico and the USVI...
Isolated flash flooding remains possible across all of the islands through
day 2 (Sun). With saturated soils in place and rivers running above normal,
any additional rainfall will quickly become runoff and could lead to rapid
river rises. Mudslides/landslides are also possible across central and
eastern Puerto Rico.

.Alaska...
In the northern Seward Peninsula, the Buckland River could rise out of its
banks as early as tonight due to ice jamming. This could lead to minor
flooding impacts in the town of Buckland.

//Freeman

$$