035
AGUS74 KWCO 261508
HMDNWC

National Hydrologic Discussion - EXPERIMENTAL
NWS National Water Center - Tuscaloosa AL
1008 AM CDT WED JUN 26 2024

.Synopsis...
Additional rounds of rainfall in the Central Plains and the Upper and
Middle Mississippi Valley... Flash flooding possible in the Four Corners
region and Northeast...Snowmelt induced flooding continues in Alaska...

.Discussion...

.Central Plains and the Upper and Middle Mississippi Valley...
Widespread moderate to major river flooding is ongoing and/or forecast
across southeast SD, southern MN, and northern IA. Record flooding is
ongoing and forecast along the Minnesota and Des Moines rivers. Much of the
ongoing major river flooding is in recession, but as the flood wave routes
downstream and additional rainfall is forecast, flooding impacts on main
stem rivers, including the Mississippi and Missouri rivers, is still to
come.

Over the next three days, additional rainfall of 1 - 4" is forecast across
eastern NE and KS, southern IA and northern MO, though the heaviest
bullseye of QPF is currently forecast to be south of the worst of the
ongoing flooding. This region received 1 - 3" (locally higher) of rain over
the last 24 hours, saturating soils, especially in southern IA and northern
MO (70 - 90% RSM, 0 - 10 cm RSM, NASA SPoRT). Additional rainfall in this
region will likely be rapidly converted to runoff into streams, rivers, and
low-lying areas. Streamflows in this region are around normal, though there
are locations along the mainstem Mississippi River where major flooding is
forecast. Within-bank rises to area streams are likely, and some localized
flooding impacts are possible. Western IL is still on the drier side and
should be able to absorb the rainfall, at least initially, without
significant flooding impacts. Flash and urban flooding is possible anywhere
heavy rainfall persists or storm training sets up.

There is potential for locally heavy rainfall forecast day 6 (Mon) across
MN and northern IA. This area will have some time to recover from ongoing
impacts before this next event, but will need to be monitored closely,
given the vulnerable antecedent conditions.

.Four Corners...
Moisture will persist over the region throughout the week, particularly in
parts of NM, AZ, and western CO, leading to locally heavy rainfall and the
potential for flash flooding. Areas that receive multiple rounds of
rainfall are more susceptible to flooding impacts as soils reach
saturation. The highest flood threat is in areas with recent burn scars,
slot canyons, dry washes, and regions where training and more persistent
storms occur.

.Northeast...
Isolated incidences of flash and urban flooding today and again on day 4
(Sat) are possible across the region as multiple frontal boundaries
generate scattered showers and storms. Outside of urban areas, the
Adirondacks and northern New England (VT/NH/ME) are most vulnerable to
hydrologic responses given wet soils (60 - 75% RSM, 0 - 10 cm NASA SPoRT)
from recent rainfall and terrain enhancement. Specifics in terms of
placement and magnitude of potential flooding impacts still remain
uncertain, and will be dependent on rainfall amounts and duration.

.Alaska...
Warming temperatures continue to cause snow and ice melt at high
elevations, leading to rivers running high in areas across Southcentral AK.
Minor flooding on the Chilkat River near Klukwan continues into early this
week, with ample snow available to melt. Minor river flooding is expected
on the Skwentna and Yentna Rivers through the week. Also, high water
continues on the Nuyakuk River near Dillingham.

//Ayala

$$